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

More documents

Recommendations

Info

REFERENCES1 White, S. R. et al. Autonomic healing of polymer composites. Nature 409, 794-797, doi:10.1038/35057232(2001).2 Moad, G. et al. Living free radical polymerization with reversible addition-fragmentation chain transfer(the life of RAFT). Polymer International 49, doi:10.1002/1097-0126(200009)49:93.0.co;2-6 (2000).3 Moad, G., Rizzardo, E. & Thang, S. H. Radical addition-fragmentation chemistry in polymer synthesis.Polymer 49, doi:10.1016/j.polymer.2007.11.020 (2008).4 Mayadunne, R. T. A., Jeffery, J., Moad, G. & Rizzardo, E. Living free radical polymerization with reversibleaddition-fragmentation chain transfer (RAFT polymerization): Approaches to star polymers.Macromolecules 36, doi:10.1021/ma021219w (2003).5 Matyjaszewski, K. & Tsarevsky, N. V. Nanostructured functional materials prepared by atom transferradical polymerization. Nature Chemistry 1, doi:10.1038/nchem.257 (2009).6 Matyjaszewski, K., Miller, P. J., Pyun, J., Kickelbick, G. & Diamanti, S. Synthesis and characterization of starpolymers with varying arm number, length, and composition from organic and hybrid inorganic/organicmultifunctional initiators. Macromolecules 32, doi:10.1021/ma9904823 (1999).7 Angot, S., Murthy, K. S., Taton, D. & Gnanou, Y. Atom transfer radical polymerization of styrene using anovel octafunctional initiator: Synthesis of well-defined polystyrene stars. Macromolecules 31,doi:10.1021/ma980712y (1998).8 Gao, H. & Matyjaszewski, K. Synthesis of star polymers by a combination of ATRP and the "click" couplingmethod. Macromolecules 39, doi:10.1021/ma060926c (2006).9 Bosman, A. W., Vestberg, R., Heumann, A., Frechet, J. M. J. & Hawker, C. J. A modular approach towardfunctionalized three-dimensional macromolecules: From synthetic concepts to practical applications.Journal of the American Chemical Society 125, doi:10.1021/ja028392s (2003).10 Hawker, C. J. et al. ''Living'' free radical polymerization of macromonomers: Preparation of well definedgraft copolymers. Macromolecular Chemistry and Physics 198, doi:10.1002/macp.1997.021980112 (1997).11 Pasquale, A. J. & Long, T. E. Synthesis of star-shaped polystyrenes via nitroxide-mediated stable freeradicalpolymerization. Journal of Polymer Science Part a-Polymer Chemistry 39, doi:10.1002/1099-0518(20010101)39:13.0.co;2-z (2001).12 Hawker, C. J., Barclay, G. G., Orellana, A., Dao, J. & Devonport, W. Initiating systems for nitroxide-mediated''living'' free radical polymerizations: Synthesis and evaluation. Macromolecules 29,doi:10.1021/ma951905d (1996).136
6. GENERAL CONCLUSIONSThe objective of this thesis was to develop and bring self-healing capability to the membranes,which had largely been confined to solid materials like composites or gels so far. As the advancesare made in chemistry every day, more and more functionalities are emerging having potential to impartthe self-mending capability to a material. To impart this capability to a membrane, the principalconstraint was to not to affect the main purpose of a membrane, i.e. its filtration behavior. The currentmethods of acquiring self-healing in a material though novel cannot be applied to prepare a membraneor more specifically a porous material in a straight forward way because of their applicationenvironment. Hence, a new and different strategy was used to approach the problem which resulted insuccessful development of a self-healing membrane.In the first part of this work, we prepared a nanomaterial based on the in situ 3-dimensional selfassemblyof triblock copolymer micelles. The copolymer, PSAN–b–PEO–b–PSAN was synthesized incollaboration with another research group with optimized molecular weight and ratio of PEO and PSAN.When dissolved in a selective mixture of DMF/Toluene solvents and spin coated onto silicon wafer, a 1.3µm film could be obtained which was essentially an in-situ self-assembly of copolymer micelles havingaverage diameter of 50 nm as observed with Atomic Force Microscopy. Despite having very lowthickness, the nanomaterial showed decent structural robustness to be able to withstand usual handlingprocedures. The interstitial volume generated between the micelles imparted the film certain degree ofporosity so as to be used as a membrane for water permeation. The constituting micelles of themembrane were held together by the copolymer chains running in between micelles’ core however dueto absence of any covalent bonding, these chains were able to dislocate easily thereby imparting acertain dynamism to the membrane. It is this inherent dynamic nature based on which the porosity ofthe membrane was found to be variable as a function of water pressure applied orthogonally onto thesurface of membrane. The porosity change was found to be a direct result of morphology change(deformation of micelles) however the interesting fact about this change was its complete reversibilitytill a certain pressure value thus giving a pressure tunable porosity to the membrane. The tunableporosity was successfully demonstrated when from mixture of poly(ethylene glycol)s, selectiveseparation was achieved as a function of pressure. Another result of the dynamic nature was the self-137
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: Figure - 3.18: Scanning Electron Mi
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: Figure - 3.24: Scanning Electron Mi
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 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 168 and 169: ELABORATION OF SELF-HEALING POLYMER
Page 170 and 171: ELABORATION DES MEMBRANES POLYMERES
show all

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

Create successful ePaper yourself

Delete template?

Save as template?