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2.4.1.1 Fabrication of Conductive Multilayers by the LbL Method Conducting polymers prepared by thin film technology have become increasingly important for electrical and optical applications. Polyaniline is one of the most promising electrically conducting polymers due to ease of synthesis, versatile processability, stable electrical conductivity, and relatively low cost. PANI is used in a wide variety of fields such as chemical sensors(Dan, Yadong, Zhiming, Xiangdong, & Yanrong, 2000; Mathur, Misra, Singh, & Tripathi, 2002), solar cells, light-weight batteries, light emitting diodes, polymer actuators, and corrosion protection agents. Shirakawa et al.(Ito, Shirakawa, & Ikeda, 1974) found that by “doping” polyacetylene, its conductivity is increased by many orders of magnitude. There are two kinds of dopants: electron acceptors (p-type dopants) such as iodine, and electron donors (n- type doping). The use of various concentrations of dopants can vary electrical properties by as much as 18 orders of magnitude, and so conductivity can be controlled in a wide range. The conductivity of the emeraldine base (EB), which is the best representation of polyaniline at ambient temperature, is about 10 -10 S/cm, while by doping it with different acids and adding sites of (-N=) to EB, emeraldine salt can be formed with a conductivity of about 5 S/cm at the same temperature(Epstein et al., 1986; Ginder, Richter, MacDiarmid, & Epstein, 1987). Ferreira et al.(Ferreira, Cheung, & Rubner, 1994) found that both aqueous and polar organic solutions of positively charged protonated forms of polyaniline and polypyrrole can be prepared, although solubility of PANI in an organic medium such as dimethylacetamide(DMA) is much higher than that in water. Nevertheless, for LbL self assembly, preferred media are aqueous solutions. The preferential affinity of certain ions for others is an important factor in film growth. In low molar mass compounds, chloride or bromide bind much stronger to the ammonium group than sulfonate does and sodium binds stronger to the sulfonate group than to chloride and bromide. For example, film growth forms smoothly using sodium poly(styrene sulfonate) and poly(N,N,Ntrimethyl-2-methacryloylethyl ammonium) bromide or poly(diallyldimethyl-ammonium) chloride(Bertrand, 2000). Rubner’s group at MIT investigated both electrostatic and hydrogen-bonded LbL assembly using fully and non-fully ionized polyelectrolyte in solution. They found that the structure of polyelectrolyte multilayer depends on the degree of ionization of the polyelectrolyte. They 70
succeeded in creating thin films with unique and quite useful properties by using weak polyelectrolytes and tuning charge densities by simple changes in solution pH. It was noted by Cheung and Rubner(Cheung, et al., 1997) that under different pH environments, a weak polyelectrolyte becomes less ionized and so a pH-sensitive trigger can be used to release the charged molecules. 2.4.1.1.1 Charged Polymer Adsorption In this section, the physical aspects of polymer adsorption are focused. From an architectural point of view, polymers can be divided into linear homopolymers, branched homopolymers, disordered linear heteropolymers, charged polymers or polyelectrolytes, and heteropolymers composed of a backbone and side-chains of different chemical nature (Figure 2-34). a) b) c) d) Figure 2-34. Schematic view of different polymer types: (a) linear homopolymers that are the main subject of this review, (b) branched polymers, (c) charged polymers or polyelectrolytes (PEs), and (d) a disordered copolymer with no specific order of the different monomers. 71
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© Sepehr Ravati, 2010. UNIVERSITÉ
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DEDICATED To my parents iii
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RÉSUMÉ Cette thèse présente, po
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devenir une structure hiérarchique
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ABSTRACT This thesis presents, for
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system can be increased from 10 -15
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CONDENSÉ EN FRANÇAIS Dans ce trav
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deuxième coquille de PS. Les phase
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structures à percolation multiple
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autre sous-type de morphologie dans
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TABLE OF CONTENTS DEDICATION.......
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xxiii 2.4.1.1.1 Charged Polymer Ads
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5.3.4 Annealing Test ..............
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xxvii REFERENCES ..................
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LIST OF FIGURES xxix Figure 1-1. a)
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Figure 2-12. SEM photomicrograph of
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Figure 2-34. Schematic view of diff
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Figure 4-8. SEM micrographs of vari
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Figure 5-6. a),b) Scanning electron
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and c) triangular concentration dia
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n number of moles p concentration o
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AFM atomic force microscopy LIST OF
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PS-co-PMMA copolymer of PS and PMMA
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1.1 Introduction CHAPTER 1 - INTROD
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Figure 1-2. Human heart, longitudin
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One of the applications for porous
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On the other hand, a novel tri-cont
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2.1 Polymer Blends CHAPTER 2 - LITE
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Based on Sterling’s approximation
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Antonoff’s rule (Equation 2-13) i
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2.1.2.1 Binary Polymer Blends 2.1.2
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Some other studies(Everaert, Aerts,
Page 65 and 66: where the parameter z is dependent
Page 67 and 68: “compatibilization” was suggest
Page 69 and 70: a) λ BC A and B are matrices, b) C
Page 71 and 72: Reignier & Favis, 2000, 2003a; Reig
Page 73 and 74: measure the interfacial tension of
Page 75 and 76: a) b) Figure 2-6. Dependence of the
Page 77 and 78: Omonov et al. found double percolat
Page 79 and 80: 2.1.2.2.3 Effect of Composition on
Page 81 and 82: a) b) C B A c) Figure 2-12. SEM pho
Page 83 and 84: In the case where PS is the matrix,
Page 85 and 86: Posthuma de Boer, 1999) (Kumin & Ch
Page 87 and 88: lattice, such as square lattice, wi
Page 89 and 90: magnetization, which is a function
Page 91 and 92: Polymers have long been thought of
Page 93 and 94: epoxy as a function of nanotube wei
Page 95 and 96: Figure 2-19. Approaching the percol
Page 97 and 98: Figure 2-21. Transmission electron
Page 99 and 100: Figure 2-22: Dependence of PE conti
Page 101 and 102: Figure 2-24. Plot of the total numb
Page 103 and 104: chain provides the conductive path
Page 105 and 106: 2.3.1.2.1 Polyaniline One of the mo
Page 107 and 108: CoPA/LLDPE/PANI blend and a poor-qu
Page 109 and 110: Narkis and co-workers extended and
Page 111 and 112: Figure 2-31: Conductivity of PVDF/P
Page 113 and 114: organic thin films, a novel and str
Page 115: on the topic have been reported in
Page 119 and 120: Addition of salt to the solution of
Page 121 and 122: different from that of linear homop
Page 123 and 124: Figure 2-39. Macromolecule with a)
Page 125 and 126: polyanion such as hyaluronan (HA)(P
Page 127 and 128: 2.4.1.1.7 Effect of Salt on Multila
Page 129 and 130: 2.4.1.1.8 Overcompensation of the M
Page 131 and 132: important factors determining the g
Page 133 and 134: As shown in Figure 2-44, swelling a
Page 135 and 136: increasing the pH value due to a de
Page 137 and 138: CHAPTER 3 - ORGANIZATION OF THE ART
Page 139 and 140: discussed above, HDPE, PS, PMMA, an
Page 141 and 142: CHAPTER 4 - LOW PERCOLATION THRESHO
Page 143 and 144: or model which predicts where the p
Page 145 and 146: concentration threshold for the ons
Page 147 and 148: chemical and weathering resistance,
Page 149 and 150: Table 4-1. Material Characteristics
Page 151 and 152: filled with blend pellets. To facil
Page 153 and 154: 4.3.6 Conductivity Measurements DC
Page 155 and 156: experimentally in this research gro
Page 157 and 158: a) b) c) d) Figure 4-4. Schematic i
Page 159 and 160: microstructure of the quaternary bl
Page 161 and 162: a) b) c) d) Figure 4-6. SEM microgr
Page 163 and 164: a) b) PVDF PS PMMA c) d) e) HDPE PS
Page 165 and 166: Uniform layers of PS and PMMA situa
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the concentration of HDPE is increa
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a) b) c) e) Figure 4-11. SEM microg
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melt-processable and contains 25 wt
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One question that should be address
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Conductivity(S/cm) Ternary Blend 1,
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phase(PMMA), the concentration of P
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(6) Virgilio, N.; Desjardins, P.; L
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ONION MORPHOLOGY HDPE PVDF PS Contr
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work described above has focused on
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thermodynamic explanation to predic
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four-point probe increases continuo
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in the rheology tests were compress
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5.3.6 Layer-by-Layer Deposition The
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prepare a polymer blend structure w
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a) b) c) Figure 5-3. Scanning elect
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spontaneously self-assembled. After
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a) b) c) d) e) f) g) h) Figure 5-5.
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Since the ultra-low surface area va
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c) a) b) Figure 5-6. a),b) Scanning
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salt to a PSS polyelectrolyte solut
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A relationship between macropore si
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close together. It is interesting t
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Figure 5-9. Mass increase (%) indic
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In this work the conductance of the
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deposited PANI layers increases unt
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(52) Guo, H. F.; Packirisamy, S.; G
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6.2 Introduction It is well-known t
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modified version of Harkins theory(
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6.3 Experimental 6.3.1 Materials Co
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Complex voscosity (Pa.s) 1,0E+04 1,
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6.3.5.2 Focused Ion Beam (FIB) and
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a) c) b) d) e) f) PMMA PMMA HDPE HD
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y Harkins theory, PS will always si
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a) b) c) d) e) f) PS Figure 6-6. a)
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a) b) HDPE : black PS : grey PMMA :
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6.4.6 Continuity, Co-continuity, an
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c) V III II I VII I IV VI Figure 6-
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Continuity Scheme (a) Figure 6-10.
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Addition of a low concentration of
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Addition of small amounts of HDPE t
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icontinuous network with the HDPE.
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Three examples are shown in Figure
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(9) Mekhilef, N.; Verhoogt, H. Poly
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structures are formed due to the co
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CONCLUSION AND RECOMMENDATIONS In t
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REFERENCES A. K. Gupta, K. R. S. (1
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Caruso, F. (2003). Hollow Inorganic
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Domenech, S. C., Bortoluzzi, J. H.,
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Geuskens, G., Gielens, J. L., Geshe
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Hou, S., Harrell, C. C., Trofin, L.
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Krass, H., Papastavrou, G., & Kurth
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Macdiarmid, A. G., Jin-Chih, C., Ha
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Niziol, J., & Laska, J. (1999). Con
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Reghu, M., Yoon, C. O., Yang, C. Y.
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Shirakawa, H., Louis, E. L., MacDia
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Utracki, L. A. (1991). On the visco
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Yasuda, K., Armstrong, R., & Cohen,
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literature has examined factors inf
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(Reignier & Favis, 2000, 2003a; Rei
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Table A-1.2. Interfacial tensions a
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acquisition of images with a very h
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Table A-1.3. Continuity of the PMMA
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(17) Reignier, J.; Favis, B. D., Ma
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PANI. Theoretically, the extent of
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Equation A-2.7 0( ) 0 1. 5 σ = σ
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Cumulative Mass × 10 5 (g) dipping
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of PANI, and an increase in the con
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Resistance(ohm) 1.0E+12 1.0E+11 1.0
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esistance value. Samples containing
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The results of resistance for PS/PE
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Caruso, F., & Schuler, C. (2000). E
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