Shampoo and Conditioner Science, Robert Y ... - Allured Books

Practical Modern Hair Science 

Chapter 3 

www.Alluredbooks.com 

Shampoo and 

Conditioner Science 

Robert Y. Lochhead 

University of Southern Mississippi 

Shampoos and conditioners are the highest volume of products 

sold in personal care. In this chapter, we will consider the science 

that underpins the functioning of these product types. The principal 

function of shampoos is to cleanse the hair. However, since the 

introduction of two-in-one shampoos in the 1970s, it has not 

been sufficient for a shampoo to merely cleanse the hair. Modern 

shampoos should at least cleanse, condition, make the hair easier 

to style, and fragrance the hair with a pleasant, lingering smell. 

Modern conditioners should lower the friction between hair fibers to 

allow easier grooming and alignment of the hair fibers while leaving 

them glossy and avoiding lankness. 

The science of shampoos and conditioners is still evolving and 

in addition to describing fundamentals, this chapter attempts 

to take the reader to the frontiers of research in shampoo and 

conditioner science. 

Introduction 

Located within the hair follicle is a sebaceous gland that 

continuously excretes an oily material, known as sebum, onto 

the hair and scalp. This substance consists of compounds such as 

fatty acids, hydrocarbons, and triglycerides, and serves as nature’s 

conditioning treatment—providing lubrication and surface 

75

Shampoo and Conditioner Science 

hydrophobicity, while potentially replenishing components of 

the cell membrane complex. However, after a day or so, buildup 

of this substance begins to result in a greasy look and feel. 

Moreover, particulate dust and dirt adhere readily to this sebum 

layer. In modern cultures such sebum-soiled hair is deemed to 

be undesirable, and therefore, it should be removed on a regular 

basis by a facile process. This process is, of course, shampooing. 

Sebum cannot be removed by water because oil and water do not 

mix. Aqueous shampoos can remove oily soil from the hair surface 

because shampoos contain surface-active agents, commonly 

abbreviated as surfactants. The molecules of these surface-active 

agents self-assemble into micelles, which are the agents that 

solubilize oily soils. 

To understand how surfactants work, it is necessary to consider 

the exact process that leads to oil and water being incompatible. 

There are two different possibilities for substances to be insoluble 

in water. In one case, substances have stronger intermolecular 

cohesion than water. This is why substances like sand, clay, and 

glass are insoluble in water; the molecules of sand attract each 

other more strongly than the molecules of water and this attraction 

leads to the sand being insoluble. This reason for the insolubility is 

exactly opposite to the reasons for the insolubility of hydrophobic 

substances such as oils. The intermolecular forces between the oil 

molecules are weaker than the intermolecular bonds between water 

molecules and the oils are expelled from water. This expulsion arises 

largely from entropy and the effect has been coined hydrophobic 

interaction. 1,2 From the time of the Phoenicians, it has been known 

that oil spreads to calm troubled waters. This effect arises from the 

fact that the spread oil has a lower surface tension than the water. At 

this point it is appropriate to consider the effect known as surface 

tension. Molecules in the bulk of liquids are attracted on all sides 

by their neighboring molecules. However, molecules at the surface 

are subjected to imbalanced forces because they are attracted by the 

underlying liquid molecules, but there is essentially no interaction 

with the vapor/gas molecules on the other side of the liquid/vapor 

76

Chapter 3 

boundary. This imbalance leads to a two-dimensional force at the 

surface, namely surface tension. The surface tension is numerically 

equal to the surface free energy. 3 The magnitude of surface tension 

directly correlates with the strength of the intermolecular forces. 

Water has hydrogen bonds, dipole-dipole interaction, and dispersion 

forces between its molecules, and as a consequence the surface 

tension of water is rather high—72 mN/meter at room temperature. 

On the other hand, only dispersion forces are present between the 

molecules of alkanes. As a consequence, the surface tension of 

alkanes is relatively low—ranging 20–30 mN/meter. 

Surfactants comprise molecules that contain two parts: a 

hydrophobic segment that is expelled by water and a hydrophilic 

segment that interacts strongly with water. Such molecules are said 

to be amphipathic (amphi meaning “dual” and pathic from the 

same root as pathos which can be interpreted as “suffering”). Thus, 

a surfactant molecule “suffers” both oil and water. This dual nature 

confers interesting properties on surfactants in aqueous solution. 

At very low concentrations, the surfactant is expelled to the surface, 

a process called adsorption. This adsorption causes the surfactant 

concentration at the surface to be much higher than the surfactant 

concentration in the bulk of the solution. At extremely low 

concentrations, when the surfactant molecules on the surface are 

located too far apart to effectively interact with each other, Traube’s 

Rule applies. Traube’s Rule states that the ratio of the surface 

concentration to the bulk concentration increases threefold for each 

CH 2 group of an alkyl chain. 4 This ratio is called the surface excess 

concentration. 5 According to this rule, soap with a dodecyl chain 

should have a surface excess concentration that is more than a halfmillion 

times its concentration in the bulk solution. At extremely 

low concentrations, the surfactant molecules on the surface act as a 

two-dimensional gas. As the concentration increases, the surfactant 

molecules begin to interact, but they are still mobile within the 

plane; they behave as two-dimensional liquids. At even higher 

concentrations, as the surfactant saturates the surface, the chains 

orient out of the surface plane and the chain-chain interactions 

77


cause the surfactant to behave as a two-dimensional solid. Irving 

Langmuir was awarded the 1932 Nobel Prize in Chemistry for 

measuring this effect and explaining it on a molecular basis. 6 

When a surfactant adsorbs to saturate an aqueous surface, the 

surface is largely composed of the surfactant’s hydrophobic groups; 

this means that the surface essentially has low surface energy. As a 

consequence of the low surface energy, the surface area is easier to 

expand to a film. This means that the system is easier to foam, since 

aqueous foams really consist of water films with entrapped gas. If 

the foam surface is structured by the adsorbed surfactant, then foam 

stability can be achieved. 7 

Surfactant Micelles 

Relatively large aggregates form within solution just beyond 

the concentration at which the surface becomes saturated with 

surfactant. 8 These aggregates are surfactant micelles in which 

the hydrophobes are segregated within the core of the aggregate 

and the hydrophilic groups are located on the surface where they 

interact strongly with water. 9 For a given system, micelles initially 

form at the precise concentration at which the driving force for 

surface adsorption becomes equal to the driving force for aggregate 

formation. This driving force is the chemical potential of the 

surfactant species. The lowest concentration at which micelles form 

is named the critical micelle concentration (CMC). The aggregates are 

large; for example, micelles of sodium dodecyl sulfate at the CMC 

contain about 100 molecules and the thickness of the head group 

layer is about 0.4 nm. 10 

Surfactant micelles have liquid centers. They effectively solubilize 

hydrophobic substances only when the temperature of the system is 

above the Krafft point. Krafft found this phenomenon in 1895, and 

68 years later Shinoda explained that the Krafft point corresponds to 

the melting point of the hydrated solid surfactant. 11 

Micelles have different shapes. The simplest shape is the 

spherical micelle that was postulated by Hartley in 1936. The 

shape of a micelle can be explained on the basis of the principle 

78

Chapter 3 

of opposing forces (see Figure 1). Two or three amphipathic 

molecules alone cannot form a stable micelle because micellization 

is essentially a cooperative process that requires the participation 

of many amphipathic molecules bound together by hydrophobic 

interaction. However, if hydrophobic interaction accounted solely 

for the formation of micelles, then the association would continue 

until phase separation occurred, as in oil separating from water. 

Therefore, there must be a force that opposes the hydrophobic 

association and controls the size of the micelles. This force is the 

repulsion between the head groups that could arise from ion-ion 

repulsion and/or hydration of the head groups. 12 Theoretically, 

the repulsive surface terms are difficult to handle from a 

thermodynamic perspective but the presence of micelles has been 

validated experimentally. 

Figure 1. The shape of a surfactant micelle is determined by 

the balance between the mutual repulsion between hydrophilic 

groups at the micelle surface and the cohesion due to hydrophobic 

interaction. This has been dubbed the principle of opposing forces. 

If micelle structure was determined solely by thermodynamics, 

spherical micelles would always be favored over other shapes. 

However, real micelles are not restricted to a spherical shape; 

spherical structures account for only a small minority of micelles. 

The shapes of surfactant molecules and the way they can be packed 

79


also plays an important role in determining micelle shape. Although 

thermodynamics and packing geometries are inextricably linked, 

by considering the limits of possible packing arrangements we can 

obtain insight into the shapes of micelles and the transformation 

from one shape to another as physical and chemical conditions 

are changed. In this context, the many shapes of micelles, arising 

from the principle of opposing forces, can be appreciated by 

considering Packing Factor Theory (Figure 2). 13 First, consider a 

spherical micelle. In this instance the micelle radius, R, the volume 

of the hydrophobic core, v, and the surface area of the amphipathic 

molecule at the hydrophobe/water interface, a, are related by: 

80 

Eq. 1 

The radius of a micelle, R, cannot exceed the fully extended 

length, l, of the hydrophobe chain of the surfactant molecule. This 

gives the critical condition for the formation of spherical micelles: 

Eq. 2 

Figure 2. The packing factor of a surfactant molecule is the volume of 

the tail group divided by the volume of the cylinder subtended by the 

head group to the length of the tail group.

Chapter 3 

The fraction, v/al, is known as the packing factor (Figure 3). 

When the packing factor has a value of 1/3, the surfactant molecule 

can be approximated by a conical shape and the molecules pack into 

a sphere (Figure 4). 

Figure 3. Surfactant molecules with a packing factor of 1/3 have a 

shape that can be approximated by a cone. 

Figure 4. These conical molecules pack naturally into a sphere. 

When the packing factor has a value of ½, the micelles become 

cylinders (Figure 5), and when the packing factor has a value of 

1, the surfactant molecules pack as planar bilayers in a so-called 

lamellar structure (Figure 6). 

For ionic surfactants, the area per head group can be decreased 

by adding soluble salt to the solution to lessen the ionic repulsion 

between the head groups. (Salt also enhances the hydrophobic 

interaction. 14 ) Increase in salt and/or surfactant concentration causes 

spherical micelles to transition to rods and then to long worm-like 

micelles. 15 The wormlike micelles behave like polymers in solution. 16 

81


These micelles also form branched as well as linear structures, and 

above a certain concentration (the critical overlap concentration, C*) 

they entangle just like polymer molecules 17 and display viscoelastic 

rheology. 18-20 This behavior is depicted in Figure 7 as it was 

explained by Candau in 1993. 21 An increase in salt concentration 

causes spherical or elliptical micelles to transition into rods, then 

to worms then to branched worms. As the surfactant concentration 

increases, the micelles form entangled networks. Consumers desire 

82 

Figure 5. Surfactant molecules with a packing factor 

of ½ pack naturally into cylinders. 

Figure 6. Surfactant molecules with a packing factor of 1 pack 

naturally into bilayer planes.

Chapter 3 

thicker shampoos, in part because they are easier to apply, but 

also for aesthetic reasons; a thicker formula is generally perceived 

as being more-luxurious. The desired rheology is achieved from 

formulations that contain worm-like micelles. 

Figure 7. Ionic surfactant micelles change shape as a function of ionic 

strength and surfactant concentration. 

Wormlike micelles do, however, show “non-polymeric” behavior 

at certain shear rates when the shear stress becomes independent of 

the shear rate and the relaxation time becomes monodisperse. 22 This 

behavior has been explained on the basis that the entanglements 

can be broken and reformed as the rod-like micelles disassemble 

and then reassemble upon passing through each other. 23-24 Systems 

like these have been dubbed “phantom networks” by Cates to 

signify that one micelle flows through another just as we imagine a 

phantom would pass through a wall. The phantom network behavior 

may explain why shampoos can show viscoelasticity without the 

“stringiness” observed in entangled polymer solutions. 

At higher concentrations, the rod-like micelles mutually repel, 

and this favors alignment into a nematic phase. At still higher 

concentrations the aligned rods pack in a hexagonal array to form 

hexagonal phase liquid crystals (Figure 8). The hexagonal phase 

has the properties of a clear ringing gel that is birefringent in 

polarized light. 

83


As the surfactant concentration is increased further and/or 

dissolved salt concentration is increased, the surface of the micelles 

becomes less curved until the large planar aggregates of the lamellar 

phase are formed (Figure 9). Modern shampoos consist essentially 

of entangled worm-like micelles and conditioners are usually in the 

form of the lamellar phase. 

In summary, shampoo and conditioner formulation essentially 

involves the preparation of surfactant mixtures that possess the 

84 

Figure 8. Rod-like micelles can pack into hexagonal liquid crystal phase. 

Figure 9. Increase in surfactant concentration causes micelles to transition from 

spheres to rods to hexagonal phase to lamellar phase to inverse hexagonal 

phase to inverse micelles.

Chapter 3 

aforementioned structures, while also being esthetically pleasing. 

The hair care formulation scientist has an ever-increasing variety 

of surfactants available in the formulation toolbox, and so these 

structures can be obtained via a wide range of concoctions. 

Nonetheless, attaining such stable structures is not a trivial task, 

due to the presence and interactions of so many ingredients in 

the typical formulation. Therefore, with historical knowledge 

involving many established ingredients already being relatively 

well-understood, it is a brave formulation chemist that opts to cut a 

new pathway. Moreover, it is also probably prudent to arrive at these 

structures in the most cost-effective manner. For these reasons, it 

is imperative to understand how the surfactant structure, together 

with interactions with other molecules alters the nature of the 

aggregate structures. 

Oily Soil Removal Mechanisms 

The principal function of a shampoo is to remove oily soil from 

the hair. There are several principal detergency mechanisms for 

removing oily soils: “roll-up,” 25 emulsification, penetration, and 

solubilization. 

In the roll-up mechanism, the detergent solution causes a steady 

increase in the contact angle of the oil at the oil/fiber/aqueous 

interface (Figure 10). 

Figure 10. In this mechanism the oil contact angle at the oil/water/fiber interface 

steadily increases until it “rolls up” and floats off of the solid surface. This 

mechanism was first reported by N. K. Adams. 

The oil droplet is rolled up on the surface, and when the contact 

angle reaches 180 degrees, the interfacial force that is holding it to 

the surface is overcome by the wetting tension of the oil and aqueous 

solutions on the fiber surface. Roll-up is favored by fibers that are 

85


oleophobic and hydrophilic. 26 The removal of oily soil by detergent 

compositions is not necessarily predictable due to the wide variation 

of the surface properties of hair that arise from prior treatments 

and weathering. Moreover, the transport of the detergent solution 

to the fiber surface can occur by three different routes: (i) along the 

fiber surface, (ii) through a previously applied permeable surface 

treatment, or (iii) through the body of the fibers (Figure 11). 

Roll-up of oily drops on fibers occurs when the contact angle 

exceeds a critical value and this causes the oily drop to adopt an 

unstable axially asymmetric attachment on one side of the fiber. 27 

The rate of roll up depends also on the viscosity of the oily soil, 

and mechanical action is often necessary to dislodge viscous oily 

soils from the fiber surface. In some cases, the oil forms a viscous 

emulsion when contacted by the detergent composition, and the 

resulting viscous soil can be difficult to remove from the fiber. 

“Perfect” hair is covered by a covalently attached monolayer of 

18-methyleicanosoic acid (18-MEA), which confers hydrophobicity 

on the hair. Modern grooming techniques and weathering removes 

this layer of 18-MEA. 28 Removal of the layer of 18-MEA results 

in hair becoming macroscopically hydrophilic. 29 The roll-up 

mechanism, therefore, should be expected to become more 

prominent on damaged rather than pristine hair. 

Initially if the fiber is completely coated in oil, or if the fiber itself 

is hydrophobic, the detersive solution cannot easily reach the oil/fiber 

interface, and the soil will be removed by emulsification (Figure 12). 

86 

Figure 11. In the roll-up mechanism, the detergent solution can be transported 

to the fiber/oil interface along the fiber surface, through a permeable coating 

on the fiber, or through the fiber itself.

Emulsification is favored by low oil/water interfacial tension that 

allows the oil surface to be expanded into an emulsion droplet. 30 

Figure 12. Emulsification can remove the soil if the interfacial tension between the 

oily soil and the surfactant solution is low. 

Chapter 3 

In the penetration mechanism of oily soil removal, surfactantrich 

phases penetrate the oil at the interface. This results in an 

interfacial liquid crystalline phase that swells and is broken off 

to reveal a fresh soil interface, and then the process is repeated 

again and again. 31 The penetration mechanism occurs with polar 

soils and/or phase separated coacervates of nonionic surfactants 

above the lower critical solution temperature (LCST). Spontaneous 

emulsification, in the absence of detersive surfactant, has been 

observed for non-polar-polar soil mixtures like sebum. 32 The 

penetration mechanism can occur with anionic surfactants that 

form coacervate phases in the presence of calcium salts. 33 

Solubilization is the process of incorporating a water-insoluble 

hydrophobic substance in the internal hydrophobic core of micelles. 

Direct solubilization can occur in the presence of an excess of 

surfactant micelles with respect to oily soil. 34 The rate of exchange 

of surfactant molecules between micelles is important because the 

micelles must re-assemble around the soil to solubilize the soil by 

encompassing it inside the micelle. 

Foam/Lather 

One essential attribute of a shampoo is its ability to produce 

a rich lather or foam. The important elements of a foam are 

the lamellae and the Plateau border. The micrograph in Figure 

13 depicts these structural features of a foam. The lamellae are 

stabilized by surfactants adsorbed at the air-water interface. 

87


Foams lose stability by two main mechanisms: draining of the 

liquid and puncture of the lamellae. The foam lamellae are the 

junctions between two foam bubble cells and the plateau border is 

situated at the triple-cell junction. The Laplace pressure in the liquid 

components of the foam is inversely proportional to the curvature 

of the interface. The higher curvature of the plateau border results 

in a lower pressure in that region and this causes the liquid in the 

foam to drain preferentially from the lamellae to the plateau borders. 

Based upon this reasoning, it can be understood that drainage can 

be hindered in two ways, namely by blockage of the lamellae or by 

blockage at the plateau border. About two decades ago, Des Goddard 

carefully measured the drainage from foam films and deduced 

that polyquaternium-24 adsorbed across the lamellar interface and 

hindered the drainage of liquid from the foam. In addition, about 

thirty years ago, Stig Friberg concluded that certain liquid crystals 

blocked the plateau border region and delayed foam drainage and 

conferred longer-term stability on surfactant foams. In the case of 

cationic polymers, hindered drainage of the lamellar liquid could be 

caused by adsorption of the cationic entities at the lamellar surface 

with the nonionic and/or anionic blocks in the lamellar liquid. 

88 

Figure 13. Micrograph showing surfactant foam structure.

Chapter 3 

Alternatively, formation of phase-separated coacervates between the 

cationic polymer and the anionic surfactant could result in blockage 

of the plateau border. Of course, if the interaction of the cationic 

polymer was strong enough to form “inverse micellar” structures, 

then there would be a possibility that the phase-separated particles 

could cause a local reversal of the curvature in the lamellae and this 

in turn would result in breakage of the lamellar film and subsequent 

foam destabilization. This type of foam destabilization mechanism 

has been extensively reported by Peter Garrett. 

Solid Foams 

Cationic conditioners 

that would normally be 

incompatible with liquid 

shampoos can be delivered 

from solid foams. Solid 

foams also make it possible 

to have one scent for the 

solid and then to allow 

a different fragrance to 

bloom when the solid is 

wetted by water. 35 The 

porous solids are made by 

mixing the surfactants, 

glycerin as a plasticizer, 

and water in the presence 

of a water-soluble polymer. 

Figure 14 shows a solid 

foam in which poly(vinyl 

alcohol) is the water-soluble 

polymer. After a heating Figure 14. Micrograph showing solid foam structure 

and mixing cycle, the (reproduced from US Patent Application 20110195098). 

porous solid is formed by 

aeration. 

89


The Anatomy of a Shampoo Formulation 

Shampoos consist essentially of water, a primary surfactant, 

one or more co-surfactants, and soluble salt. Other ingredients 

are added for fragrance, preservation, conditioning, and styling 

attributes. Cleaning is achieved mainly by the primary surfactant, 

which is often an anionic surfactant that would adopt a conical 

shape if it was present in water alone. The co-surfactant is usually 

a nonionic or zwitterionic surfactant with a relatively small head 

group surface area. This molecular shape allows the co-surfactant 

to serve two roles: (i) it packs between the molecules of the primary 

surfactant to reduce the curvature and to promote the formation 

of worm-like micelles with their high viscosity and luxurious 

rheology; and (ii) it packs between the primary surfactant in the 

lamellae of the foam to provide good lather that is easily removed 

by rinsing. Salt enhances the function of the co-surfactant by 

“damping down” the ionic repulsion between primary surfactant 

head groups and promoting the formation of wormlike micelles. If 

excess salt or co-surfactant is added, shampoo compositions can 

separate into phases that contain co-existing micelles and liquid 

crystals. These phase-separated compositions often exhibit thin 

viscosities and haziness. 

The Primary Surfactant 

The lauryl sulfates have been the primary surfactant workhorses 

of the shampoo industry for decades. The sulfate head groups bear 

an anionic charge when dissolved in water. The long chain alkyl 

tail group has an average length of 12 carbon atoms. It is important 

to understand that this is an average chain length; commercial 

lauryl sulfates have a distribution of chain length from as short as 

8 carbons to as long as 18 carbons. This chain length distribution 

changes from supplier to supplier and it also changes depending 

on the source of raw materials. Formulators should be aware that 

changes in the chain length distribution of the surfactants can lead 

to subtle changes in the properties of the shampoo. 

90

Chapter 3 

During the 1970s, triethanolamine lauryl sulfate was preferred 

as a primary surfactant due to its excellent cleaning properties and 

luxurious flash foaming capability. However, it was replaced by 

laureth sulfates for two reasons: the concern over the formation of 

nitrosamines from secondary amine components and the reduced 

eye irritation exhibited by the laureth sulfates. 

Over the last two decades, the primary surfactants of most 

shampoos have been sodium laureth sulfate, ammonium lauryl 

sulfate, and sodium lauryl sulfate. 

The co-surfactant–often called the foam booster–has most 

prominently been selected from two types of materials: alkylamide 

MEA and alkylamidobetaines. Modern shampoos contain primarily 

betaines as co-surfactants. 

Enhancing Mildness 

Isethionates are surfactants noted for their mildness to skin, 

and for at least three decades, they have been the basis of non-soap 

detergent bars such as Dove (Unilever). They have been making 

inroads into shampoos based upon mildness claims. Moreover, 

Unilever researchers discovered that the mildness can be enhanced 

even further by including mildness benefit agents that can be 

flocculated by cationic polymers present in the formulation and 

delivered as flocs upon dilution of the formulation. 36 The preferred 

benefit agent in this case is petrolatum; the cationic polymers 

are well known polymers like polyquaternium-10 and guar 

hydroxypropyltrimonium chloride. This could form the basis of 

shampoos that are mild to the skin. 

Certain non-cross-linked linear acrylic copolymers can lower 

the irritation potential of surfactants and provide products that are 

clear and highly foaming. 37 The preferred polymers interact with the 

surfactant and effectively shifting the CMC to higher concentrations, 

while lowering the critical aggregation concentration—the latter 

being the concentration at which the surfactant selectively interacts 

with the polymer rather than adsorbing at the liquid surface 

(Figure 15). It is postulated that free surfactant molecules and 

91


free surfactant micelles are responsible for irritation of skin and 

eyes and that binding of the surfactant to the polymer effectively 

reduces the concentration of free micelles. A measure of mildness 

is the delta CMC, which is defined as the difference between the 

CMC of the surfactant alone and the higher CMC of the surfactant 

in the presence of the polymer. Larger values of delta CMC for a 

particular surfactant are apparently correlated with lowering of the 

irritation potential. The delta CMC provides a measure that is useful 

for selecting, comparing, and optimizing polymers that reduce the 

irritation potential of selected surfactant systems. Carbomer and 

acrylates copolymer have been identified as polymers that exhibit a 

satisfactory delta CMC. 

Conditioning Shampoos 

Today’s conditioning shampoos are expected to confer wet-hair 

attributes of hair softness and ease of wet-combing, and the dry hair 

attributes of good cleansing efficacy, long-lasting moisturized feel, 

and manageability with no greasy feel. 

The origin of conditioning shampoos can be traced to the 

balsam shampoos of the 1960s followed by the introduction of 

polyquaternium-10 by Des Goddard 38,39 in the 1970s and 1980s in 

which he introduced the concept of polymer-surfactant complex 

coacervates that phase-separate and deposit on the hair during 

92 

Figure 15. Plot of surface tension vs. surfactant concentration for 

surfactant alone and for surfactant in the presence of polymer. The 

difference in the CMC induced by the presence of the polymer is 

claimed to be related to the effect of the polymer in enhancing the 

mildness of a shampoo.

Chapter 3 

rinsing. The first two-in-one shampoos depended on a complex 

coacervate being formed between anionic surfactant and the 

cationic hydroxyethylcellulose, polyquaternium-10. This complex 

was solubilized in excess surfactant and it phase-separated as a 

coacervate liquid phase upon dilution during the rinsing cycle. 

Later guarhydroxypropyltrimonium chloride was introduced as 

an alternative cationic polymer that worked on the same principle 

as polyquaternium-10. These two polymer types continue to 

dominate the compositions of conditioning shampoos. 40 Guar is a 

galactomannan and it is interesting that, in recent years, recently 

a new cationic galactomannan hydrocolloid, cationic cassia, 

has been claimed to confer conditioning shampoo benefits. 41,42 

Polygalactomannans consist of a polymannan backbone with 

galactose side groups. In guar gum, there is a pendant galactose 

side group for every two mannan backbone units. These galactose 

groups sterically hinder the substitutable C-6 hydroxyl unit, 

limiting the extent of possible cationic substitution on guar gum. 

In cassia, however, there is less steric hindrance of the C-6 hydroxyl 

group and, consequently, higher degrees of cationic substitution 

are possible with cassia (60% for cassia relative to 30% for guar). 

Cationic cassia can be used as a conditioning polymer in shampoos 

and conditioners to impart cleansing, wet-detangling, drydetangling, 

and manageability. 

The mechanism of conditioning shampoos depends upon the 

formation of polymer/surfactant coacervates that phase-separate 

during rinsing (Figure 16). Polyions in aqueous solution are 

surrounded by an electrical double-layer of counterions, and the 

location of the counterions with respect to the polyion is determined 

by a balance between chemical potential and electrochemical 

potential, called the Donnan Equilibrium. Surfactant ions contain a 

large hydrophobic group that makes them intrinsically less soluble 

in water than inorganic ions such as chloride or bromide. When 

surfactant ions interact with an oppositely charged polyion, they 

bind strongly and displace the water-soluble inorganic ions from 

the polyion; that is, they ion-exchange. Once the surfactant ions 

93


bind, hydrophobic interaction between the hydrophobic surfactant 

tails causes the polymer-surfactant complex to phase separate at 

concentrations below the surfactant critical micelle concentration. 

Above the CMC, the surfactant concentration is sufficiently high 

to form micelles or hemi-micelles along the polyion chain, and the 

polyion/surfactant complex is solubilized. Conditioning shampoos 

are formulated within the range of surfactant concentrations that 

correspond to this solubilized regime. When these shampoos are 

diluted to a concentration that is in the vicinity of the CMC, then the 

complex coacervate phase-separates. The separated phase is deposited 

on the hair during rinsing, and it can co-deposit other additives such 

as silicone conditioning agents or anti-dandruff agents. Maximum 

coacervate deposition occurs at precise ratios of cationic polymer to 

anionic surfactant, but the optimum ratio for coacervation might not 

coincide with the best ratios for cleaning and foaming. 

Cationic guar has been a known additive for 2-in-1 shampoos 

for more than three decades. However, it has now been shown that 

improved post-shampoo detangling times are achieved by including 

a small degree of hydrophobic substitution in the cationic guar 

derivatives. 43 

94 

Figure 16. A schematic phase diagram that explains the mechanism of coacervate 

formation in 2-in-1 shampoos.

Chapter 3 

Synthetic copolymers of acrylamide and a Triquat monomer are 

postulated to provide improved deposition on hair and improved 

conditioning performance with respect to wet combing. 44 

Silicones have become standard ingredients in many conditioning 

shampoos for the smooth, silky hair feel that they confer. Silicones 

were introduced to shampoos as 2-in-1 conditioning agents in 

the 1980s. The introduction of silicones needed to overcome two 

substantial deficiencies: (i) silicones are well known defoamers, and 

(ii) silicones are incompatible with typical shampoo compositions 

and they tend to separate due to their low specific gravity. Initial 

attempts to stably suspend the silicone included the use of water– 

miscible saccharides such as corn syrup. 45 Later products comprised 

xanthan gum in the shampoo as a suspending agent and acceptable 

foaming attributes were conferred on the shampoos by formulating 

with relatively high levels of alkyl sulfates as the primary surfactant, 

cocamide MEA as the co-surfactant, and ethylene glycol distearate 

as a surfactant structuring agent. 46 In the actual application, there 

is a technical contradiction involved in the deposition of silicone 

conditioning components from a detersive, cleansing system; 

the detersive system is designed to remove oil, grease, dirt, and 

particulate material from the hair, and the conditioning agent 

has to be deposited on that same hair in one process. As a result, 

large excess amounts of silicone are used to ensure deposition, 

and one consequence of this is that large amounts of the expensive 

conditioning silicone can be rinsed away rather than deposited on 

the hair. Cationic polymer/anionic surfactant coacervates enhance 

the deposition of silicones on hair and, consequently, increase the 

efficiency of conditioning shampoos. 47,48 

Volatile cyclic siloxanes confer the desired silky initial feel, but 

these materials are difficult to formulate in consistent homogenous 

formulations, They tend to spread uncontrollably over the hair and 

skin. 49 This effect can be controlled with polymeric silicone gels 

formed in volatile silicones to provide both the initial silky feel and a 

high viscosity and smooth feel when dry. 50 Branched molecules with 

a silicone core and hydrocarbon branches, or networks formed from 

95


these branched units, have been disclosed as suitable for improving 

sensory feel, while minimizing phase separation and conferring 

good shampoo removability. 51 

Shampoos containing more than one cationic conditioning 

polymer and a quaternary silicone give more uniform deposition on 

hair than standard shampoos based on polyquaternium-10 as the 

sole conditioning polymer. Thus, a conditioning polymer “cocktail” 

comprising poly(acrylamide-co-acrylamidopropyltrimonium) 

chloride, guar hydroxypropyltrimonium chloride, and silicone 

quaternium-13 give uniform deposition on hair. In this instance, the 

claims are based upon multiple testing and analysis: 52 

96 

• A multiple attribute consumer assessment study that measured 

the attributes of cleanliness, wet-comb, dry-comb, hair softness, 

lather amount, and creaminess. 

• Secondary Ion Mass spectrometry to detect silicon on the hair 

surface. This method revealed that a standard commercial 

shampoo concentrated silicone on the cuticle edges of the hair, 

whereas the patent application shampoo “distributed silicone 

more evenly.” 

• X-ray photoelectron spectroscopy (XPS) to measure the thickness 

of the silicone polymer layer on hair from Si:C:O ratios. This 

method revealed that the commercial shampoo deposited 

a significant amount of silicone, and the patent application 

shampoo deposited only one or two molecular layers. 

• Instron ring compression as a measure of combability. 

Complex coacervates can also be formed from mixtures of 

cationic and anionic polymers. This could be the underlying 

mechanism in shampoos that include an anionic and cationic 

polymer that provide sleekness and gloss. 53 

Two drawbacks of silicones are that they often destabilize foam 

and the final compositions are hazy due to light scattered from 

the suspended silicone droplets. Initially, silicone copolyols were 

introduced to overcome the insolubility of silicones in shampoo 

compositions, but this drastically reduced the amount of silicone

Chapter 3 

deposited onto hair and compromised conditioning performance. 

Clear, silicone-containing conditioning shampoos have been 

formulated by adding trideceth-2 carboxamide MEA to reduce the 

silicone droplet size. 54 Transparent conditioning shampoos can be 

formulated by incorporating the silicone as microemulsified droplets, 

but the small microemulsion droplets tend to be rinsed away rather 

than deposited during the shampooing process. Moreover, coalescence 

of the droplets can lead to loss of transparency in the product during 

storage. Attempts have been made to overcome these challenges by 

including silicone emulsions with high internal viscosities, typically 

greater than 100,000 centistokes, but the high internal phase viscosity 

gives deposited silicone that is can be difficult to remove and this 

causes buildup with each consecutive shampooing. Such buildup 

usually reduces the volume of the desired hair style and causes 

“droop” and flatness. Fortunately, shampoo compositions providing 

superior conditioning to hair while also providing excellent storage 

stability and optionally high optical transparency or translucency can 

be obtained by combining low viscosity microemulsified silicone oil 

with cationic cellulose polymers and cationic guar polymers having 

molecular weights of at least about 800,000 and charge densities 

of at least about 0.1 meq/g. 55 Conditioning shampoo formulations 

that include a silicone microemulsion in a conditioning shampoo 

containing guar hydroxypropyltrimonium chloride and an anionic 

detersive surfactant have also been reported to be clear. 56,57 If pregelatinized 

starch, such as hydroxypropyl distarch phosphate, is 

included with polyquaternium-10, transparent conditioning shampoos 

can be obtained. 58 

Another way to minimize buildup is to treat the hair with waterin-water 

emulsions that can be prepared by including cationic 

polymers with soluble salts in surfactant compositions. 59 These waterin-water 

emulsions provide conditioning benefits with good spread 

of the conditioning phase on the hair and less chance of buildup. 

The living free radical polymerization techniques that have 

emerged in the last decade offer the prospect of preparing precise 

polymers with unprecedented accuracy in molecular structure and 

97


variety of chemical types. 60 This technique has enabled synthesis of 

a wide diversity of block and graft polymers that were previously 

unattainable. Such polymers offer the prospect of conferring 

conflicting properties within one molecule, which in turn can lead 

to improved compatibilities in the same system while maintaining 

stability. These conflicting properties could possibly be achieved 

by blending different polymers, but different polymers do not mix 

readily at the molecular level and phase separation may result. 61 

Block, graft, and gradient copolymers serve to compatibilize such 

compositions and gradient polymers have been proposed for this 

purpose. Block copolymers comprising polycationic blocks and 

nonionic blocks for surface deposition 62 and for improved foam 

retention 63 have been claimed, which are desired to deposit on 

hair in order to modify the chemical properties of the surface 

for protection or compatibility; to modify hair’s hydrophobic or 

hydrophilic surface properties; or to modify feel or mechanical 

properties of the substrate from two-in-one products. The polymers 

disclosed are block copolymers of polyTMAEAMS (methylsulfate 

[2-(acryloyloxy)ethyl]-trimethylammonium) g/mole) and 

polyacrylamide. 

Conditioning shampoos can also be formulated to function 

by mechanisms other than cationic polymer-induced complex 

coacervation, such as: 

98 

• Conditioning can be achieved by including chain extended 

silicones in an anionic surfactant-based shampoo. Specific 

examples of useful silicones include silicone emulsions 

containing divinyldimethicone/dimethicone copolymer. 64 

• Shampoos containing polyalkylene oxide alkyl ether particles 

give larger coacervate cohesive flocs (20–500 microns) that 

resist shear and confer superior deposition efficiency on hair for 

good wet conditioning. 65 

• Conditioning shampoos containing a polyester formed from 

adipic acid and pentaerythritol provides conditioning for dry 

hair (possibly from reduced hair friction), with no greasy feel. 66

• Inclusion of polybutene is thought to increase the deposition 

of silicone conditioners and provide improved conditioning 

benefits, such as wet and dry feel and combing. 

Chapter 3 

O’ Lenick disclosed a unique class of alkyl polyglucoside quaternary 

surfactants possessing all the multifunctional attributes of cleansing, 

conditioning, and self-preserving. 67 This could have the potential of 

greatly simplifying the formulation of multifunctional shampoos. 

A conditioning shampoo that contains a conditioning gel 

phase in the form of vesicles is described by Unilever researchers. 68 

Cationic conditioners are usually incompatible with anionic 

shampoos, and consequently conditioners based upon cationic 

surfactants are usually applied as separate post-shampoo products. 

The Unilever researchers prepared a conditioning gel phase by 

combining a small amount of water, fatty alcohol, a long-chain 

secondary anionic surfactant (sodium cetostearyl sulfate), and 

a long-chain cationic surfactant (behenyltrimethylammonium 

chloride), and subjecting the mixture to high shear to form a stable 

vesicular gel phase. Prolonged shear causes the lamellar gel phase to 

roll-up into an array of multilamellar vesicles (Figure 17). The gel 

phase was added to a dilute primary surfactant solution (sodium 

laureth sulfate) to form a conditioning shampoo that conferred good 

wet smoothness on hair. 

Figure 17. Lamellar gel subjected to high shear rolls up into vesicles of gel phase that can 

be used for conditioning. (Figure reproduced from US Patent Application 20110243870). 

Deposition of Particles on Hair to Confer Styling Benefits 

Whereas conditioning shampoos are formulated to reduce hair 

inter-fiber friction, some consumers need an increase in friction in 

99


order to achieve styling benefits. Factors that influence hair body 

and fullness include hair diameter, hair fiber-to-fiber interactions, 

natural configuration (kinky, straight, wavy), bending stiffness, 

hair density, and hair length. Increases in friction can be achieved 

by depositing particles such as titanium dioxide, clay, pearlescent 

mica, or silica on the hair surface. Particles can be deposited for 

more purposes than merely increasing inter-fiber friction, e.g., for 

conferring color, for slip (spherical particles are best for this), and 

for conditioning (hollow silica, hollow polymer particles). Hollow 

particles can be included in shampoo to increase hair volume. 69,70 

Deposited hollow particles that can increase fiber-fiber interaction 

include complexes of gas-encapsulated microspheres (such as silica 

modified ethylene/methacrylate copolymer microspheres and 

talc-modified ethylene/methacrylate copolymer microspheres); 

polyesters; and inorganic hollow particles. 

It has already been noted that cationic guar enhances 

the deposition of conditioning agents. In a like manner, this 

macromolecule enhances the deposition of particles on hair. 71 

Silicones and particulates can be deposited simultaneously. Thus, 

enhanced deposition of particulate actives, such as zinc pyrithione 

(shown on cadaver skin treated in a Franz diffusion cell), has 

been reported 72 from shampoos comprising a water-soluble 

silicone (such as silicone quaternium-13, cetyltriethylammonium 

dimethicone copolyol phthalate, or stearalkonium dimethicone 

copolyol phthalate), a cationic conditioning agent (such as 

acrylamidopropyltrimonium chloride/acrylamide copolymer, or 

guar hydroxypropyltrimonium chloride), a cleansing detergent, 

and suspending agents (such as carbomer, hydroxyethylcellulose, 

and PVM/MA decadiene cross-polymer) to insure homogeneous 

distribution of the insoluble active. 

Hydrophobic modification of cationic hydroxyethylcellulose 

is claimed to endow better efficacy. Thus, polyquaternium-24, 

a hydrophobically modified cationic hydroxyethylcellulose, is 

also disclosed as being a preferable thickener for zinc-depositing 

compositions. 73 

100

Chapter 3 

It has been discovered that responsive particles, with two 

contrasting polymers adsorbed to the particle core, 74 can adsorb 

to the hydrophilic hair surface and render it hydrophobic, thereby 

conferring conditioning attributes to the hair. For example, grafting 

of aminopropyl-terminated dimethicone and polyethylenimine 

on titanium dioxide particles produces responsive particles. 

These particles form stable dispersions in water and aqueous 

solutions because they are sterically stabilized by expansion of 

the polyethylenimine into the aqueous medium. However, when 

they are deposited on hair and dried, the polyethylenimine layer 

collapses and the dimethicone layer expands to render the surface 

hydrophobic. The usefulness of these responsive particles is 

demonstrated by including them in typical conditioning shampoo 

and conditioner formulations. In the case of the shampoo, inclusion 

of the responsive particles results in a higher water contact angle on 

the treated hair and the conditioner with particles causes an increase 

in the hydrophobicity of the hair. On the other hand, shampoos 

containing ethoxylated alcohols have been found to enhance the 

deposition of large particle silicones (5–2000 microns), and in this 

case it is claimed that cationic polymer is not required. 75 

Two-phase Systems for Visual Attributes: 

There is esthetic appeal to products that exist as separate phases 

in the bottle but which mix during application to provide added 

benefit, such as moisturizing or conditioning, by interaction of the 

components of the two phases. The most obvious way to formulate 

such products is to use the immiscibility of water and oil in 

formulations that are shaken prior to use to produce a metastable 

emulsion. However, when a surfactant is included in the system such 

a visually attractive phase separation can be mixed into an emulsion 

due to shear in manufacturing and packing operations. There are 

known de-emulsifiers, which are widely used in the oil industry, 

but these demulsifiers also tend be defoamers that compromise the 

lather of shampoos. Neutralized polyacrylate can be added as a nonemulsifying 

foam stabilizer to yield phase-separated compositions 

101


that resist the production difficulties to make phase-separated 

shampoos that form temporary emulsions upon shaking and foam 

during use. 76 A two-phase shampoo system can also be formed by 

mixing polar lipophilic shampoo components with non-polar lotion 

constituents such as mineral oil. 77 

Under appropriate conditions, phase-separated systems can be 

prepared from polymer solutions or micellar surfactant solutions. If 

two distinct aqueous phases are desired in a composition, one must 

take into consideration the thermodynamics of coexisting phases 

and the driving force for such phase separation that comes directly 

from the chemical thermodynamics of the system. This is especially 

the case for systems that contain polymers or micelles because the 

configurational entropy is reduced as molecules are assembled 

into polymers or aggregated into micelles, and mixing can become 

unfavorable. If the free energy of mixing is insufficient to maintain 

uniform dispersion, spontaneous phase separation will occur. 

Phase separation becomes more likely as the micellar aggregates or 

polymers get bigger. The addition of salts to ionic surfactant micellar 

systems causes a reduction in the surfactant intra-micellar headgroup 

interaction, and often an increase in hydrophobic interaction. 

This can cause a pronounced increase in micelle size and consequent 

phase separation into a surfactant-rich phase and a surfactant-poor 

phase. This approach has been adopted by adding mineral salt to 

induce two distinct layers, 78 and by adding the detergent builder, 

sodium hexametaphosphate, to cause phase separation. In this case, 

a thickener is required and the system comprises a surfactant, a 

thickener, a polyalkylene glycol, and a non-chelating mineral salt. 

The system spontaneously separates into two layers. 

A multiphase composition comprising surfactant, betaines, 

co-surfactant (such as an alkyl ether carboxylate, an acylglutamate; 

or an acylisethionate), and an appropriate concentration of salt 

forms a stable multiphase system that becomes temporarily 

uniformly dispensed upon agitation. 79 

Multiphase cleansing products have been introduced that go 

beyond mere phase separation insofar as the separate phases can be 

102

Chapter 3 

arranged to form visually attractive patterns inside a transparent 

container. 80 The phases comprise an aqueous cleansing phase, a 

benefit phase, and a non-lathering structured phase. The aqueous 

cleansing phase must be capable of adequate lathering. 81 The 

benefit phase comprises hydrophobic component(s) or conditioning 

components. These products are designed at the nanoscale: the 

structured phase can be a lamellar-phase formed by adding sufficient 

electrolytes to an appropriate surfactant. Structurants such as 

starch have been used in personal cleansing formulations, 82 but the 

surfactant itself can be structured. Thus, lamellar phase does exhibit 

a yield stress that is sufficient to stably suspend the benefit phase. 

However, the yield stress of lamellar phase can vary dramatically 

with temperature, and, in order to overcome this problem, the 

cleansing and benefit phases were density matched by adding 

microsphere particles to reduce the specific gravity of the cleansing 

phase or high density particles to the benefit phase to increase its 

specific gravity. In this context, it is interesting that it has been 

recently disclosed that controlled phase separation and deposition 

could conceivably be achieved by loading the desired “active” phase 

into hollow-sphere polymer carriers, 83 and again it has been reported 

that certain cationic guar derivatives can enhance the deposition of 

conditioning additives and/or solid particle benefit agents. 84 

Lamellar phase, especially if it is made from unneutralized longchain 

fatty acids, usually displays poor dispersion kinetics and a 

lather that is slow to build up or slow to rinse off. However, it has 

surprisingly been discovered that swollen lamellar gels can exhibit 

both high product viscosity and fast dispersion kinetics if they are 

formed by combining C16-24 normal monoalkylsulfosuccinates 

with n-alkyl fatty acids of approximately the same chain length. 85 In 

this context, Guth claimed a composition that was low-irritating to 

skin and eyes but synergistic in foaming by combining zwitterionic 

surfactants-fatty acid complexes with sulfosuccinates, 86 and Pratley 

reported synergistic foaming and mildness from compositions 

with combinations of specific long-chain surfactants with specific 

short-chain surfactants and these included fatty acids and 

103


alkylsulfosuccinnates. 87 Amine-oxide copolymers have also been 

claimed as suds-enhancers. 88 

Concentrated Cleansing Compositions 

Most personal care products are based on aqueous compositions 

but concentrated cleansing/personal care compositions offer 

the benefits of lower transportation costs, less packaging, and 

convenience for air travelers. If these products are solid, they 

must possess sufficient strength to resist the forces of extrusion 

during manufacture, shipping, and handling, but should disperse 

rapidly in water during use. Porous solid particles that are 

strengthened by hydrophilic polymers such as poly(vinyl alcohol) 

or hydroxylpropylmethylcellulose have been shown to exhibit the 

desired properties. 89 Control of interconnectivity of the porous 

network is vital to this application and is described by a star volume, 

a structure model index, or a percent open cell content. 

Conditioners 

Conditioning of damaged hair is commonly achieved by 

treatment with aqueous formulations that contain fatty alcohols, 

cationic surfactants, and (optionally) silicones. These components 

are considered to adsorb in a hydrophilic head-down, hydrophobic 

tail-up conformation that confers hydrophobicity on the damaged 

hydrophilic hair surface. The role of a conditioner is to confer sleek 

lubricity and gloss on the hair. Conditioners are usually based 

upon cationic surfactants, and they most often are in the form 

of emulsions of multi-lamellar vesicles. Conditioners comprise a 

primary cationic surfactant, a co-surfactant, and dissolved salt. 

Conventional conditioner formulations are based upon lamellar 

gels or emulsions using either ceto-stearyl trimethylammonium 

chloride or distearyldimethylammonium chloride as cationic 

surfactants and ceto-stearyl alcohol as co-surfactant. 

As a primary surfactant, the vast majority of conventional 

conditioners contain either cetyl/stearyl trimethylammonium 

104

Chapter 3 

chloride or distearyldimethylammonium chloride. The secondary 

surfactant is most often ceto-stearyl alcohol. 

Cetyl/stearyl trimethylammonium chloride is a conical molecule 

according to Ninham’s packing factor. On the other hand, cetostearyl 

alcohol consists of molecules with the approximate shape 

of an inverted conical molecule. The role of ceto-stearyl alcohol 

in a conditioner is to pack between the cationic cones and convert 

the micellar structure into a lamellar structure with just enough 

curvature to form a vesicle. Distearyldimethylammonium chloride 

spontaneously forms vesicles in the presence of salt, and therefore 

there is usually no need to add a long-chain alcohol to conditioner 

formulations based upon distearyldimonium chloride. 

These products form a gel matrix that confers conditioning 

benefits from rinse-off products. They have been the basis of hair 

conditioners for the last half-century, and they provide excellent 

detangling, wet- and dry-combing, and good anti-static properties, 

but they can leave the hair feeing lank and greasy, and they give a 

long-lasting slippery feel during rinsing which is perceived by some 

consumers as an unclean hair feel. 

Pristine hair, as it emerges from the scalp, is coated with a 

covalently bound layer of 18-methyleicanosoic acid (18-MEA). 90-92 

It has been shown that the layer of 18–MEA confers hydrophobicity 

and boundary lubrication on hair fibers. 93 This discovery has 

influenced researchers to seek to include 18-MEA in conditioner 

formulations. 94 Pristine hair shows a measured advancing water 

contact angle that is high, but a receding contact angle that is 

likewise high, and the hair tends to align. However, once the 

18-MEA layer is removed, the receding contact angle is low (even 

approaching 0 degrees), and this corresponds to cuticle edges that 

are essentially hydrophilic. This means that the major differences 

for such 18-MEA deficient hair would be in its drying behavior 

rather than its wetting characteristics. The low receding contact 

angle would tend to “pin” the water to the hair. This would 

lead to longer drying times during which the capillary forces 

imparted by the water between hair fibers would tend to cause 

105


the hair fibers to clump and entangle. The inclusion of 18-MEA 

in prototype conditioner formulations that were based upon 

stearoxypropylmethylamine, dimethylaminopropylstearamide, and 

stearyltrimethylammonium chloride left the conditioner on the 

hair surface, and this in turn yielded improvements in inter-fiber 

lubricity due to improved deposition at the hair surface. 

Conditioning Polymers in Hair Straightening Applications 

The two main processes for relaxing or straightening hair are 

hair treatment with a reducing agent to cleave the disulphide cystine 

bridges (S—S) within the hair structure, and treatment of stretched 

hair with a strong alkaline agent. 

Repeated relaxation treatments can cause significant hair damage, 

to both the cuticles and the cortex. The damage can be assessed by 

measuring the porosity of the hair, and the porosity of the keratin 

fibers can be measured by fixing 2-nitro-para-phenylenediamine 

at 0.25% in an ethanol/buffer mixture (10:90 volume ratio) at pH 

10 at 37°C for 2 minutes. Cationic and amphoteric polymers, such 

as polyquaternium-6, polyquaternium-7, and polyquaternium-39, 

added to hair relaxer formulations, mitigate this degradation of the 

hair structure. Also, the inclusion of high molecular-weight (>106 

g/mole) copolymers of acrylamide and diallyldimethylammonium 

chloride, acryloyloxytrimethylammoniumchloride, or 

acryloyloxyethyldimethylbenzylammonium chloride in the relaxing 

formula results in significant reduction in the hair structural 

damage caused by alkaline relaxation. 

Conditioning Polymers 

Cationic conditioning polymers are used to enhance the 

conditioning properties, especially to mitigate the effects of extreme 

processing that are experienced during hair-straightening. Cationic 

polymeric conditioners can improve wet combability and ameliorate 

electrostatic charging of the hair (manifested by flyaway). 

Many cationic polymers have been developed for the purpose 

of conferring conditioning properties on hair. In fact, there are 

106

Chapter 3 

now more than one hundred polyquaternium ingredients listed in 

the INCI dictionary, and this list is still expanding. The primary 

purpose of polyquaternium polymers is to confer good conditioning 

benefits. A non-exhaustive list of conditioning polymers is shown in 

Table 1. 

Table 1. Examples of cationic conditioning polymers 

Chitosan 

Cocodimonium hydroxypropyl hydrolyzed Collagen 

Cocodimonium hydroxypropyl hydrolyzed hair Keratin 

Cocodimonium hydroxypropyl hydrolyzed Keratin 

Cocodimonium hydroxypropyl hydrolyzed Wheat protein 

Cocodimonium hydroxypropyl Oxyethyl Cellulose 

Steardimonium hydroxyethyl Cellulose 

Stearyldimonium hydroxypropyl hydrolyzed Oxyethyl Cellulose 

Guar hydroxypropyltrimonium Chloride 

Starch hydroxypropyltrimonium Chloride 

Lauryldimonium hydroxypropyl hydrolyzed Collagen 

Lauryldimonium hydroxypropyl hydrolyzed Wheat protein 

Stearyldimonium hydroxypropyl hydrolyzed Wheat protein 

polyquaternium-4 


Cationic hydroxyethylcellulose 


hydrophobically modified cationic hydroxyethylcellulose 

poly(methacryloxyethyltrimethylammonium methosulfate) 

poly(N-methylvinylpyridinium chloride) 

Onamer M (polyquaternium-1), peI-1500 (poly(ethylenimine) 


polyquaternium-5-poly(acrylamide-methacryloxyethyltrimethylammonium 

ethosulfate)] 

polyquaternium-6 poly(dimethyldiallylammonium chloride) 


poly(acrylamide-co-dimethyldiallylammonium chloride) 

107


Table 1. Examples of Cationic Conditioning Polymers (Cont.) 



108 

[poly-(N-vinyl-2-pyrrolidone-methacryloxyethyltrimethylammonium ethosulfate)] 

polyquaternium-16 [Co(vinyl pyrrolidone-vinyl methylimidazolinium chloride) 




poly(sodium acrylate – dimethyldiallyl ammonium chloride) 



polyvinylpyrolidone-methacrylamidopropyltrimethylammonium chloride) 


poly(N,N-dimethylaminopropylacrylate-N-acrylamidine-acrylamideacrylamidine-acrylic 

acid-acrylonitrile) ethosulfate 


poly(dimethyldiallylammonium chloride–sodium acrylate–acrylamide) 


poly(acrylamide-acrylamidopropyltrimoniumchloride-2-acrylamidopropyl 

sulfonate-DMapa) 


poly (vinyl pyrrolidone--imidazolinium methosulfate) 


poly (vinylcaprolactam-vinylpyrrolidone-imidazolinium methosulfate) 


poly (acrylic acid-methacrylamidopropyltrimethyl ammonium chloride–methyl 

acrylate) 



poly(vinylpyrrolidone-dimethylaminopropylmethacrylamide-lauryldimethylpropy 

lmethacrylamido ammonium chloride) 

pVp/Dimethylaminoethyl Methacrylate Copolymer 

Vp/DMapa acrylate Copolymer 

pVp/Dimethylaminoethylmethacrylate polycarbamyl 

polyglycol ester

Table 1. Examples of Cationic Conditioning Polymers (Cont.) 

pVp/Dimethiconylacrylate/polycarbamyl polyglycol ester 

Quaternium-80 (Diquaternary polydimethylsiloxane) 

poly(vinylpyrrolidone--dimethylamidopropylmethacrylamide) 

Vp/Vinyl Caprolactam/DMapa acrylates Copolymer 

amodimethicone 

peG-7 amodimethicone 

trimethylsiloxyamodimethicone 

Ionenes 

poly(adipic acid-dimethylaminohydroxypropyldiethylenetriamine) 

poly (adipic acid-epoxypropyldiethylenetriamine) (Delsette 101) 

Silicone Quaternium-8 

Silicone Quaternium-12 

Chapter 3 

Polyampholytes have been commercially available as 

conditioning polymers for a considerable time. A prominent 

example is polyquaternium-39, which is a copolymer of 

diallyldimethylammonium chloride, acrylamide, and acrylic acid. 

When this is polymerized in a single batch process, the mismatch 

in reactivity ratios between these monomers results in a lack of 

compositional uniformity. An improved version of this type of 

terpolymer of diallyldimethylammonium chloride, acrylamide, and 

acrylic acid has been made by a monomer feed method for better 

control of molecular weight and composition. 95 

Copolymers comprising a diallylamine (typically diallyldimethyl 

ammonium chloride) and vinyllactam monomers (typically 

polyvinylpyrrolidone) are useful film-formers that confer 

conditioning properties such as good wet and dry combability, feel, 

volume, and handleability. 96 

Silicone Conditioners 

Silicone quaternaries have long been known as hair conditioning 

compounds. 

109


A recent patent application from Evonik Goldschmidt is 

directed to silicone quats that confer conditioning with longer 

lasting conditioning through several shampoo cycles. The premise 

is that long-term substantivity to hair requires the conditioning 

agent to contain a string of cationic charges. This was achieved 

by Goldschmidt by polymerizing cationic monomers and 

grafting them to silicone backbones. In general, water-soluble 

monomers polymerized in the presence of silicones yield a 

mixture of water-soluble polymers and unsubstituted silicones 

because the two ingredients are incompatible and attachment 

of the polymer chain to the silicone would require appropriate 

“coupling groups.” The Evonik researchers rose to the challenge 

by polymerizing the cationic monomers in the presence of 

silicone polyethers. The ether groups are compatible with the 

quat monomers, and they readily chain transfer to give graft 

copolymers. Once grafted, the copolymers are quaternized to 

confer permanent positive charges with enhanced substantivity 

to hair. The grafts are obtained by polymerizing the readily 

available monomers, dimethylaminoethylmethacrylate, or 

3-trimethylammoniopropyl-methacrylamide. 

Leave-on silicone conditioners specifically targeted to nonshampoo 

applications confer enhanced and relatively durable 

conditioning. These contain emulsified vinyl-terminated silicones 

applied in combination with a conventional cationic conditioner. A 

preferred product type is a mousse. These silicone block copolymers 

can achieve excellent conditioning at relatively high viscosities (100 

KPa/s-1). 

Improved conditioning that confers surprisingly reduced friction 

on hair can be achieved by including an aminosilicone in which the 

aminosilicone has a fairly large range of average particle sizes from 

about 5–50 microns. 97 

References 

1. C Tanford, The Hydrophobic Effect: Formation of Micelles and Biological Membranes, 

Ch 1, Wiley Interscience: New Jersey (1980). 

110

Chapter 3 

2. HS Frank and MW Evans, Free volume and entropy in condensed systems: iii. Entropy 

in binary liquid mixtures; partial molal entropy in dilute solutions; structure and 

thermodynamics in aqueous electrolytes, J Chem Phys, 13, 507-533 (1945). 

3. JT Davies and EK Rideal, Interfacial Phenomena, Ch 1, Academic Press: Waltham, MA, 

(1961). 

4. J Traube, Ueber die Capillaritätsconstanten organischer Stoffe in wässerigen Lösungen, 

Justus Liebigs Annalen der Chemie, 265, 27-55 (1891). 

5. JW Gibbs, The Collected Works of J. Willard Gibbs, Longmans: New York (1928). 

6. I Langmuir, The constitution and fundamental properties of solids and liquids, II. Liquids, 

J Amer Chem Soc, 39, 1848-1906 (1917). 

7. KJ Mysels, Soap Films: Studies of their thinning, Pergamon Press: Oxford (1959). 

8. JW McBain, Colloidal electrolytes: Soap solutions and their constitution, J Amer Chem 

Soc, 42, 426-460 (1920). 

9. GS Hartley, Aqueous Solutions of Paraffin-chain Salts, Hermann & Cie: Paris (1936). 


pp 85, Wiley Interscience: New Jersey (1980). 

11. K Shinoda, N Yamaguchi, A Carlsson, Physical Meaning of the Krafft Point: Observation 

of Melting Phenomenon of Hydrated Solid Surfactant at the Krafft Point, J Phys Chem, 

93, 7216-7218 (1989). 


pp 57, Wiley Interscience: New Jersey (1980). 

13. JN Israelachvili, DJ Mitchell and BW Ninham, Theory of self-assembly of hydrocarbon 

amphiphiles into micelles and bilayers, Faraday Trans. 2, J Chem Soc, 72, 1525-1568 

(1976). 

14. MG Cacace, EM Landau, JJ Ramsden, The Hofmeister series: salt and solvent effects on 

interfacial phenomena, Quart Rev Biophys, 30, 241-177 (1997). 

15. S Candau, A Khatory, F Lequeux, F Kern, Rheological behaviour of wormlike micelles: 

Effect of salt content, Journal de Physique IV, 03, C1, 197-209 (1993). 

16. JF Berret, J Appell, G Porte; Linear rheology of entangled wormlike micelles, Langmuir, 

9 (11), 2851–2854 (1993). 

17. E Buhler, JP Munch and SJ Candau, Dynamical properties of wormlike micelles: A light 

scattering study, J Phys II France, 5, 765-787 (1995). 

18. H Rehage and H Hoffmann, Rheological properties of viscoelastic surfactant systems, 

J Phys Chem, 92, 4712–4719 (1988). 

19. H Hoffmann, Viscoelastic surfactant solutions, in: Structure and Flow in Surfactant 

Solutions, CA Herb and RK Prud’homme, eds, ACS Symposium Series 578, American 

Chemical Society (1994). 

20. PA Hassan, SJ Candau, F Kern, and C Manohar, Rheology of wormlike micelles with 

varying hydrophobicity of the counterion, Langmuir, 14, 6025–6029 (1998). 

21. F Lequeux and S J Candau, Dynamical properties of wormlike micelles, in: Structure 

and Flow in Surfactant Solutions, CA Herb and RK Prud’homme, eds, ACS Symposium 

Series 578, American Chemical Society (1994). 

22. JF Berret, Transient rheology of wormlike micelles, Langmuir, 13, 2227–2234 (1997). 

23. NA Spenley, ME Cates, and TCB McLeish, Nonlinear rheology of wormlike micelles, Phys 

Rev Lett 71, 939–942 (1993). 

24. ME Cates, Theoretical modeling of viscoelastic phases, Structure and Flow in Surfactant 

Solutions, CA Herb and RK Prud’homme, eds, ACS Symposium Series 578, American 

Chemical Society (1994). 

25. NK Adam, J Soc Dyers Colour, 53, 122 (1937). 

26. E Kissa, Wetting and detergency, Pure & Appl. Chem, 53, 2255-2268 (1981). 

27. BJ Carroll, Equilibrium conformations of liquid drops on thin cylinders under forces of 

capillarity. A theory for the roll-up process. 

111


28. R Molina, F Comelles, MR Julia, P Erra, Chemical modifications of human hair studied by 

means of contact angle determination. 

29. V Dupres, D Langevin, P Guenon, A Checco, G Luengo, and F Leroy, Wetting and 

electrical properties of the human hair surface: Delipidation observed at the nanoscale, 

J Colloid Interface Sci, 306, 34-40 (2007). 

30. CA Miller and KH Ramey, Solubilization-emulsification mechanisms of detergency, 

Colloids and Surfaces A, Physicochemical and Engineering Aspects. 74, 169-215 (1993). 

31. ASC Lawrence, The mechanism of detergence, Nature, 183, 1491 (1959). 

32. DG Stevenson, Surface Activity and Detergency, K Durham, ed., MacMillan: London 

(1961). 

33. CA Miller and KH Ramey, Solubilization-emulsification mechanisms of detergency, 

Colloids and Surfaces A, Physicochemical and Engineering Aspects. 74, 169-215 (1993). 

34. BJ Carroll, The kinetics of solubilization of nonpolar oils by nonionic surfactant solutions, 

J Colloid Interface Sci, 79, 126-135 (1981). 

35. JR Glenn et al, Porous, Dissolvable Solid Substrate and Surface Resident Coating 

Comprising Water Sensitive Actives, US Patent Application 20110195098, Aug 11, 2011; 

US Patent Application 20110189247, Aug 4, 2011; US Patent Application 20110189246, 

Aug 4, 2011; US Patent Application 20110182956, July 28, 2011. 

36. LS Tsaur et al, Personal Wash Cleanser Comprising Defined Alkanoyl Compounds, 

Defined Fatty Acyl Isethionate Surfactant Product and Skin or Hair Benefit Agent 

Delivered in Flocs Upon Dilution, US Patent Application 20110245125, Oct 6, 2011, 

assignee CONOPCO, INC., D/B/A UNILEVER. 

37. JJ Librizzi et al, Low-irritation compositions and methods of making the same, US Patent 

Application 20100311628, Dec 9, 2010, assignee Johnson & Johnson. 

38. ED Goddard, Polymer–surfactant interaction: Part II Polymer and surfactant of opposite 

charge, in: Interactions of Surfactants with Polymers and Proteins, ED Goddard and 

KP Ananthapadmanabhan, eds, CRC Press (1993). 

39. ED Goddard, Polymer/surfactant interaction in applied systems, in: Principles of Polymer 

Science and Technology in Cosmetics and Personal Care, ED Goddard and JV Gruber, 

eds, Marcel Dekker (1999). 

40. P. Brand, et al, Cleansing formulations comprising non-cellulosic polysaccharide with 

mixed cationic substituents, US Patent 8,076,279, Dec 13, 2011, assigned to Hercules 

Inc. 

41. F. Utz, et al, Cationic cassia derivatives and applications therefore, US Patent 7,439,214, 

Oct 21, 2008, assigned to Lubrizol Advanced Materials, Inc. 

42. CA Lepilleur, Cationic cassia derivatives and applications therefore, US Patent 7,704,934, 

April 27, 2010; US Patent 7,923,422, April 12, 2011, assigned to Lubrizol Advanced 

Materials, Inc. 

43. E Baldaro, et al, Home And Personal Care Compositions, US Patent Application 

20110189248, Aug 4, 2011. 

44. MM Peffly, et al, Personal care compositions containing cationic synthetic copolymer 

and a detersive surfactant, US Patent Application 20070207109, Sep6, 2007, assigned to 

The Procter & Gamble Company. 

45. M. Pader, Shampoo compositions comprising saccharides, US Patent 4,364,837, 

Dec 21, 1982, assigned to Lever Brothers Company. 

46. RE Bolich, Jr., and TB Williams, Shampoo compositions containing nonvolatile silicone 

and xanthan gum, US Patent 4,788,006, Nov 29, 1988, assigned to the Procter & 

Gamble Company. 

47. J Parran, Detergent compositions containing particle deposition enhancing agents, 

US Patent 3,761,418, Sept 25, 1973, assigned to the Procter & Gamble Company. 

48. MJ Fair, et al, Bars comprising benefit agent and cationic polymer, US Patent 6,057,275, 

May 2, 2000, assigned to Unilever Home and Personal Care USA. 

112

Chapter 3 

49. MJ O’ Brien, Cosmetic compositions using polyether siloxane copolymer network 

compositions, US Patent Application, 2005/0197477, Sept 8, 2005, assigned to 

GEAM- Silicones. 

50. TN Biggs and GE LeGrow, Lightly cross-linked poly(n-alkylmethylsiloxanes) and methods 

of producing same, US Patent 5,493,041, Feb 20 1996, assigned to Dow Corning 

Corporation. 

51. J. A. Kilgour, et al, Branched organosilicone compound, US Patent Application 

2005/0165198, July 28, 2005, assigned to GE Plastics. 

52. SM Niemiec, et al, Novel detergent compositions with enhanced depositing, conditioning 

and softness capabilities, US Patent Application 2003/0176303, Sept 18, 2003. 

53. M Maubru, Cosmetic composition comprising at least one anionic surfactant, at least 

one cationic polymer and at least one amphiphilic, branched block acrylic copolymer 

and method for treating hair using such a composition, US Patent 7,498,022, March 3, 

2009, assigned to L’Oreal S.A. 

54. H Denzer, et al, Transparent aqueous compositions comprising hydrophobic silicone oils, 

US Patent 6,803,050, Oct 12, 2004, assigned to Kao Chemicals Europe S.L. 

55. MM Peffly and JE Hilvert, Conditioning shampoo compositions, US Patent Application 

20050158266, July 21, 2005, assigned to The Procter & Gamble Company. 

56. MM Peffly, et al, Clear personal care compositions containing a cationic conditioning 

polymer and an anionic surfactant, US Patent Application 20040234483, Nov 25, 2004, 

assigned to The Procter & Gamble Company. 

57. MM Peffly, et al, Clear personal care compositions containing a cationic conditioning 

polymer and an anionic surfactant, US Patent Application 20040234484, Nov 25, 2004, 

assigned to The Procter & Gamble Company. 

58. H Albrecht, et al, Hair shampoo containing pregelatinized, cross-linked starch derivatives, 

US Patent 7,279,449, Oct 9, 2007, assigned to Beiersdorf A.G. 

59. F Simonet and L Nicolas-Morgantini, Cosmetic composition of water-in-water emulsion 

type based on surfactants and cationic polymers, US Patent 20070237733, Oct 11, 2007. 

60. VM Coessens, K Matyjaszewski, Fundamentals of Atom Transfer Radical Polymerization, 

J Chem Ed, 87, 916-919 (2010). 

61. C Farcet, Gradient copolymer, composition including same and cosmetic make-up or 

care method; US Patent Application 20090047308, Feb 19, 2009, assigned to L’Oreal. 

62. N Cadena, et al, Method for depositing a polymer onto a surface by applying a 

composition onto said surface, USPatent 6,906,128, June 14, 2005, assigned to Rhodia 

Chemie. 

63. V Bergeron, et al, US Patent 7,335,700, Feb 26, 2008; US Patent 7,915,212, March 29, 

2011; and US Patent 7,939,601, May 10, 2011, assigned to Rhodia Inc. 

64. Q Stella, Shampoo containing a silicone in water emulsion, US Patent Application 

20030143177, July 31, 2003, assigned to the Procter & Gamble Company. 

65. DR Royce and RL Wells, Shampoo containing an alkyl ether, US Patent 7,087,221, 

Aug 8, 2006, assigned to the Procter & Gamble Company. 

66. DR Royce and RL Wells, Shampoo containing an ester oil, US Patent application 

20030138392, July 24. 2003, assigned to the Procter & Gamble Company. 

67. AJ O’Lenick, Jr, et al, Personal care products based upon surfactants based upon alkyl 

polyglucoside quaternary compounds, US Patent 6,881,710, April 19, 2005, assigned to 

Colonial Chemical Inc. 

68. MJ Cooke, et al, Conditioning shampoo comprising an aqeuous conditioning gel phase 

in the form of vesicles, US Patent Application 20110243870, Oct 6, 2011. 

69. S Midha, et al, Shampoo containing hollow particles, US Patent Application 

20030086896, May 8, 2003, assigned to The Procter & Gamble Company. 

70. S Midha, BD Hofrichter, Composition for improving hair volume, US Patent Application 

20030091521, May 15, 2003, assigned to The Procter & Gamble Company. 

113


71. RL Wells, ES Johnson, Shampoo containing a cationic guar derivative, US Patent 

6,930,078, Aug 16, 2005, assigned to The Procter & Gamble Company. 

72. SM Niemiec, et al, Detergent composition with enhanced depositing, conditioning and 

softness capabilities, US Patent 6,495,498, Dec 17, 2002; US Patent 6,858,202, Feb 

22, 2005; US Patent 6,908,889, June 21, 2005, assigned to The Procter & Gamble 

Company. 

73. MF Neibauer, et al, Personal care compositions comprising a non-binding thickener with 

a metal ion, US Patent Application 20070009472, Jan 11, 2007, assigned to The Procter 

& Gamble Company. 

74. IC Constantinides, et al, Personal care compositions comprising responsive particles, 

US Patent Application 20070196299, Aug 13, 2007, assigned to The Procter & Gamble 

Company. 

75. T Yeoh, et al, Conditioning shampoo compositions having improved silicone deposition, 

US Patent 6,200,554; March 13, 2001, assigned to The Procter & Gamble Company. 

76. DR Weimer, Liquid detergent compositions, US Patent 3,718,609, Feb 27, 1973, assigned 

to Continental Oil Company. 

77. Olson, Shampoo composition possessing separate lotion phase, US Patent 3,810,478, 

May 14, 1974, assigned to Colgate-Palmolive Company. 

78. JR Williams, et al Separating multiphase personal care composition in a transparent or 

translucent package, US Patent 6,429,177, Aug 6, 2002, assigned to Unilever Home & 

Personal Care USA, division of Conopco, Inc. 

79. C Littau, et al, Multiphase aqueous cleaning compositions, US Patent 7,012,049, March 

14, 2006, assigned to Clariant International Ltd. 

80. KS Wei, et al, US Patent Application 20050100570, May 12, 2005, assigned to The 

Procter & Gamble Company. 

81. JA Wagner, et al, US Patent Application 20050192188, Sept 1, 2005, assigned to The 

Procter & Gamble Company. 

82. LS Tsaur, Personal polymer liquid cleansers stabilized with starch structuring system, 

US Patent 6,903,057, June 7, 2005, assigned to Unilever Home & Personal Care USA, 

division of Conopco, Inc. 

83. SPJ Ugazio, Polymer carriers and process, US Patent Application 20050203215, 

Sept 15, 2005, assigned to Rohm & Haas Company. 

84. RL Wells and ES Johnson, Shampoo containing a cationic guar derivative, US Patent 

6,930,078, Aug 16, 2005, assigned to The Procter & Gamble Company. 

85. Q Qiu, et al, Ordered liquid crystal cleansing composition with C16-24 normal 

monoalkylsulfosuccinates and C16-24 normal alkyl carboxylic acids, US Patent 

Application 20050136026, June 23, 2005, assigned to Unilever Intellectual Property 

Group. 

86. JJ Guth, DL Spilatro, RJ Verdicchio, Detergent compositions, US Patent 4,435,300, 

March 6, 1984, assigned to Johnson & Johnson Baby Products Company. 

87. SK Pratley, Aqueous cleansing composition, US Patent 6,001,787, Dec 14, 1999, 

assigned to Helene Curtis, Inc. 

88. MR Sivik, et al, Compositions and method for using amine oxide monomeric unit 

containing suds enhancers, US Patent 6,900,172, May 31, 2005, assigned to 

the Procter & Gamble Company. 

89. RW Glenn Jr., et al, Personal care compositions, especially those personal care 

compositions in the form of an article that is a porous, dissolvable solid structure, 

US Patent Application 20090232873, Sept 17, 2009. 

90. DJ Evans, et al, Separation and analysis of the surface lipids of the wool fiber, Proc. 7th 

Int. Wool Text. Res. Conf., Tokyo, Japan, I, 135–142 (1985). 

91. PW Wertz and DT Downing, Integral lipids of human hair, Lipids, 23, 878–881 (1988). 

114

Chapter 3 

92. PW. Wertz and DT Dowing, Integral lipids of mammalian hair, Comp Biochem Physiol, 

92B, 759–761 (1989). 

93. U Kalkbrenner, et al, Studies on the composition of the wool cuticle, Proc. 8th Int. 

Wool Text. Res. Conf., Christchurch, New Zealand, I, 398 (1990); CM Carr, et al, X-ray 

photoelectron spectroscopic study of the wool fiber surface, Textile Res J, 56, 457 

(1986); S Breakspear, et al, Effect of the covalently linked fatty acid 18-MEA on the 

nanotribology of hair’s outermost surface, J Struct Biol, 149, 235–242 (2005); CA Torre, 

et al, Nanotribological effects of silicone type, silicone deposition level, and surfactant 

type on human hair using atomic force microscopy, J Cosmet Sci, 57, 37–56 (2006); 

M Yasuda, J Hair Sci, 95, 7–12 (2004); ML Tate, et al, Quantification and prevention of hair 

damage, J Soc Cosmet Chem, 44, 347–371 (1993). 

94. H Tanamachi, et al, Deposition of 18-MEA onto alkaline-color-treated weathered hair to 

form a persistent hydrophobicity, J Cosmet Sci, 60, 31–44 (2009). 

95. JJ Sabelko, et al, Low molecular weight ampholytic polymers for personal care 

applications, US Patent Application 20070207106, Sept 6, 2007, assigned to the Nalco 

Company. 

96. L Chrisstoffels, et al, Polymers comprising diallylamines, US Patent Application 

20070191548, Aug 16, 2007. 

97. ES Baker, et al, Conditioning composition comprising aminosilicone, US Patent 

8,017,108, Sept 13, 2011, assigned to the Procter & Gamble Company. 

115


116

Shampoo and Conditioner Science, Robert Y ... - Allured Books

Create successful ePaper yourself

Delete template?

Save as template?