4(%3)3 - Ecole nationale supÃ©rieure de chimie de Montpellier

More documents

Recommendations

Info

ELABORATION OF SELF-HEALING POLYMERIC MEMBRANESThe objective of this thesis is to develop such kind of polymeric membranes which can repairthemselves autonomously in an event of damage. Such damage in a membrane, if leftundetected can pose serious health issues in some of the intended applications. In the firstapproach, a dynamic polymeric membrane based on ABA type triblock copolymer micelles hasbeen prepared. The block “A” is represented by mechanically robust poly(styrene-coacrylonitrile)copolymer while block “B” by relatively soft and flexible poly(ethylene oxide). Whenpressure is applied to the membrane, its morphology can be fine-tuned thanks to thecompressible nature of micelles as well as intermicellar dynamic bridges. A range of porositiesare accessible which can be regulated by pressure and thereby controlling the filtrationperformance. The same dynamic nature has also been utilized to display an effective pressuredriven autonomous healing. The efficiency of healing process has been found to be dependent onthe extent of damage, pressure value and time duration of application of pressure. Using theself-healing property of above membrane, “Direct Mode Translocation” of nanoparticles has alsobeen studied. Four different classes of nanoparticles were used with varied intrinsic and extrinsicproperties. The findings of the work prove that the size, shape and surface characteristics of thenanoparticles as well as the applied force govern the translocation process. In a secondapproach, a 2D and 3D reversible coating based on the self-assembly of micelles of diblockcopolymer consisting of poly(methyl methacrylate) (PMMA) and poly(n-octadecyl methacrylate)(PODMA) blocks have been developed. The assembly of micelles is accomplished via so called“Zipper” effect, thanks to the long pendant chains of PODMA block. The same “zipper” effectplays the role of removing the coating easily by washing in a selective solvent, thus giving theability to alter the surface of substrate for many times in reversible manner. The roomtemperature crystallization of PODMA block provides huge implications for a thermally assistedself-healing coating without affecting the global micelle morphology. Finally, another approachhas been conceptualized in which self-healing occurs via encapsulated nano-gel dispersed withina membrane. The nano-gel is based on a partially crosslinked hydrophilic star shaped blockcopolymer which has to be synthesized by “Reversible Addition-Fragmentation Transfer” (RAFT)
polymerization technique. The synthesis of a 4- arm RAFT agent for polymerization has beenaccomplished however; a substantial amount of work is still needed to validate the syntheticroute towards the nano-gel synthesis as well as its further application for the self-healingprocess.Key Words: Self-healing, Block Copolymer, Translocation, Dynamic bonds, Membrane, Filtration,Self-Assembly, Controlled Radical Polymerization
Page 1:
THESISPRESENTED ATNATIONAL GRADUATE
Page 4 and 5:
As the human civilization progress
Page 6 and 7:
CHAPTER - 1 SELF-HEALING POLYMERIC
Page 8:
8.1.5 Atomic Force Microscopy …
Page 11 and 12:
Synthetic engineering materials in
Page 13 and 14:
esponse to a specific external stim
Page 15 and 16:
The first work based on this approa
Page 17 and 18:
een prepared from urea-formaldehyde
Page 19 and 20:
monomer systems. The addition of EN
Page 21 and 22:
Figure - 1.10: Self-healing process
Page 23 and 24:
was required to reach healing effic
Page 25 and 26:
In addition to above works, some ot
Page 27 and 28:
that have been identified to be tak
Page 29 and 30:
part of the chapter, these material
Page 31 and 32:
Figure - 1.17: Self-healing of the
Page 33 and 34:
commercialized under tradenames; Nu
Page 35 and 36:
joined together at temperature high
Page 37 and 38:
Inspired by these findings, the fir
Page 39 and 40:
temperature greater than 80 o C in
Page 41 and 42:
Figure - 1.27: Sulfur chemistry bas
Page 43 and 44:
A different kind of sulfur chemistr
Page 45 and 46:
Figure - 1.29: Dynamic covalent che
Page 47 and 48:
cracks. The recovered droplets afte
Page 49 and 50:
23 White, S. R. et al. Autonomic he
Page 51 and 52:
65 Taber, D. F. & Frankowski, K. J.
Page 53 and 54:
107 Kushner, A. M., Vossler, J. D.,
Page 55:
148 Park, J. S., Kim, H. S. & Hahn,
Page 58 and 59:
The value of subscripts “n”,
Page 60 and 61:
The formation of spherical micelles
Page 62 and 63:
the micelle assembly showed the pre
Page 64 and 65:
gain onto the electrodes by buildin
Page 66 and 67:
The resistance R can be further exp
Page 68 and 69:
empty-tower velocity U only depends
Page 70 and 71:
This apparent morphological switchi
Page 72 and 73:
In a further qualitative analysis,
Page 74 and 75:
noteworthy and though its feasibili
Page 76 and 77:
Furthermore within this range, lowe
Page 78 and 79:
Figure - 2.22: Scanning Electron Mi
Page 80 and 81:
While the resistance measurements g
Page 82 and 83:
In conclusion, a self-healing membr
Page 84 and 85:
23 Giacomelli, F. C., Riegel, I. C.
Page 86 and 87:
micelles enabled the membrane to se
Page 88 and 89:
The second class is represented by
Page 90 and 91:
To avoid the probable clogging of t
Page 92 and 93:
181614SP2 - iNumber of Particles121
Page 94 and 95:
1000900800y = 3E+06xR² = 0,9911y =
Page 96 and 97:
very high value of 1.5 g.l -1 . Thi
Page 98 and 99:
Since the only change in the membra
Page 100 and 101:
100Retention (%)8060400,100,20,40,6
Page 102 and 103:
Page 104 and 105:
(Figure - 3.20). A cursory look at
Page 106 and 107:
When compared to poly(styrene) NPs,
Page 108 and 109:
Page 110 and 111:
REFERENCES1 Metzler, R. & Klafter,
Page 112 and 113:
46 Bemporad, D., Luttmann, C. & Ess
Page 114 and 115:
In this chapter, preparation of 3D
Page 116 and 117: obtain complex macromolecular archi
Page 118 and 119: The polymerization was conducted at
Page 120 and 121: proceeds, lesser monomer is availab
Page 122 and 123: mg/ml),the micelles’ hydrodynamic
Page 124 and 125: Figure - 4.15: The monolayer and mu
Page 126 and 127: monolayer of micelles and topmost l
Page 128 and 129: The presence of the dispersed micel
Page 130 and 131: Heating the multilayer micelle asse
Page 132 and 133: stable zipping of the micelles. Mul
Page 134 and 135: 24 Moad, G., Rizzardo, E. & Thang,
Page 136 and 137: The concept of nano-gel based self-
Page 138 and 139: Figure - 5.4: Size distribution of
Page 140 and 141: In a typical process, the two compo
Page 142 and 143: Figure - 5.10: 1HNMR spectra obtain
Page 144 and 145: The 1 HNMR spectrum obtained for th
Page 146 and 147: REFERENCES1 White, S. R. et al. Aut
Page 148 and 149: healing ability shown by the membra
Page 150 and 151: 7. PERSPECTIVESBeing the first such
Page 153 and 154: 8. MATERIALS & METHODSThis chapter
Page 155 and 156: 8.1.3 PEG Filtration MeasurementsTh
Page 157 and 158: addition of TEOS due to formation o
Page 159 and 160: solution was ultrasonicated for 15
Page 161 and 162: Triethylamine (TEA) (Sigma-Aldrich
Page 163 and 164: To prepare the monolayer assembly o
Page 165 and 166: was added followed by addition of 0
Page 170 and 171: ELABORATION DES MEMBRANES POLYMERES
show all

4(%3)3 - Ecole nationale supÃ©rieure de chimie de Montpellier

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?