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

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When compared to poly(styrene) NPs, the silica NPs are more stiffer and rigid in nature. Hence,when comparing the nanoparticles having same size of above two species, the poly(styrene) ones willpass through the membrane easily by easily undergoing deformation and thus lower retention. On theother hand, the silica ones can only form aggregates having much more irregular shapes thus furthercomplicating their translocation and consequently giving a higher retention.The perforations observed on the top surface of the membrane (Figure – 3.21a), does not meanthat healing process has been hindered in case of a stiffer nano-object. When the size distribution ofthese perforations is compared with the size distribution of silica SP1 NPs, a significant difference can beseen (Figure – 3.22). The explanation of still opened pore can either be due to entrapment of silica NPsinside the membranes thus destabilizing the natural equilibrium of the micelles which would otherwisein usual case, force them to come back to their original position to heal the space created.76Number of Perforations54321017 21 25 29 33 37 41 45 49 53 57 61 65 69 73 77 81 85 89 93 97 101Diameter (nm)Figure – 3.22: Size distribution of perforations observed in the Scanning Electron Microscopy image of top surface ofa membrane fed with silica SP1 NPs.The transverse section SEM image of one such membrane fed with SP1 series NPs reveals a layerof agglomerated NPs within the membrane before they reached the end of the membrane (Figure –3.23). Above this layer, other NPs can also be seen. The thickness of the membrane was found to be well96
above that of normal value. This agglomeration of NPs within the membrane is perhaps responsible fornegligible permeation observed SP1 series and also for the unhealed perforation observed on the topsurface of the membrane.Figure – 3.23: Scanning Electron Microscopy images of transverse section of a membrane with entrapped silica NPs.The increased thickness can be observed easily due to the space occupied by the trapped NPs inside.When a very high concentration of nanoparticles was used and the filtration time extended to 48hours, an irreversible reorganization of the micelle assembly was observed, as revealed by themembrane autopsy (Figure – 3.24). It seems that at such high NP concentration, the pores remainedopen for an extended time and the continuous flow of solid silica NPs inside the pores induced analignment of micelles along the direction of flow.97
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THESISPRESENTED ATNATIONAL GRADUATE
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As the human civilization progress
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CHAPTER - 1 SELF-HEALING POLYMERIC
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8.1.5 Atomic Force Microscopy …
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Synthetic engineering materials in
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esponse to a specific external stim
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The first work based on this approa
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een prepared from urea-formaldehyde
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monomer systems. The addition of EN
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Figure - 1.10: Self-healing process
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was required to reach healing effic
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In addition to above works, some ot
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that have been identified to be tak
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part of the chapter, these material
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Figure - 1.17: Self-healing of the
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commercialized under tradenames; Nu
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joined together at temperature high
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Inspired by these findings, the fir
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temperature greater than 80 o C in
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Figure - 1.27: Sulfur chemistry bas
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A different kind of sulfur chemistr
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Figure - 1.29: Dynamic covalent che
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cracks. The recovered droplets afte
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23 White, S. R. et al. Autonomic he
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65 Taber, D. F. & Frankowski, K. J.
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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 104 and 105: (Figure - 3.20). A cursory look at
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
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addition of TEOS due to formation o
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solution was ultrasonicated for 15
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Triethylamine (TEA) (Sigma-Aldrich
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To prepare the monolayer assembly o
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was added followed by addition of 0
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ELABORATION OF SELF-HEALING POLYMER
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ELABORATION DES MEMBRANES POLYMERES
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4(%3)3 - Ecole nationale supÃ©rieure de chimie de Montpellier

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