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This apparent morphological switching can also be visualized via cyclic change in resistancevalues (Figure – 2.13), where three successive increasing/decreasing cycles of the transmembranepressure have been carried out. The 1 st run, stopped below the threshold pressure, showed a stronghysteresis, which can be due to an increase in the contact surface area between micelles duringcompression, thus facilitating PEO interactions. Novel copolymer bridges formation seems to be realisticsince the resistance is maintained while decreasing the pressure, attesting the presence of strong linksbetween the deformed micelles. However, with removal of water pressure, the 2 nd run matches closelythe 1st run during the pressure increase, in agreement with a good reversibility betweensphere/spheroid morphologies. Interestingly, beyond 3.5 bar, the 3 rd run shows almost no hysteresisbeing reliable to the large pores worm-like network of very low resistance, which is the usual behaviourof classical membranes.2.6 ATOMIC FORCE MICROSCOPY EVIDENCE FOR MORPHOLOGY CHANGEThe perpetual changes in the porosity and resistance of the membrane with respect to pressureindicate clearly towards the morphological changes. To prove this, the membranes were analyzed usingAFM after being subjected to water pressure followed by drying at room temperature in a dry chamberfor 1 day. The Atomic Force Microscopy (AFM) images revealed that when subjected to a 4 bar waterflow, there is rearrangement of the spherical particles into a more compact ordering (Figure – 2.14a, b, c,d). Till 2.5 bar, the films showed ability to retrace their original resistance value until a thresholdpressure value is reached, indicating that the system’s morphology was resilient enough to counter thepressure change in agreement with AFM observation. This resilience comes from the hard core-softcorona nature of the micelles and is also due to copolymer chains running through them interconnectingeach other. At 3 bar, the micelles begin to irreversibly deform from spheres to spheroids (Figure –2.14d). This deformation becomes much more pronounced at 3.5 bar (Figure – 2.14e) and further at 4bar when the most of the micelles collapse to irreversibly give a “worm like” network with uneven largevoids formation, leading to a significant porosity change (Figure – 2.14f). These large voids explain thesudden large increase in the porosity and thus decrease in resistance calculated at pressures 3 bar.60
Figure – 2.14: Atomic Force Microscopy images obtained for different membranes showing the evolution ofmorphology with respect to pressure.Figure – 2.15: Binary color images obtained from corresponding Atomic Force Microscopy images to obtainapproximate pore size and their evolution with pressure.61
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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
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 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 106 and 107: When compared to poly(styrene) NPs,
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
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proceeds, lesser monomer is availab
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mg/ml),the micelles’ hydrodynamic
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Figure - 4.15: The monolayer and mu
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monolayer of micelles and topmost l
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The presence of the dispersed micel
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Heating the multilayer micelle asse
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stable zipping of the micelles. Mul
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24 Moad, G., Rizzardo, E. & Thang,
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The concept of nano-gel based self-
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Figure - 5.4: Size distribution of
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In a typical process, the two compo
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Figure - 5.10: 1HNMR spectra obtain
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The 1 HNMR spectrum obtained for th
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REFERENCES1 White, S. R. et al. Aut
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healing ability shown by the membra
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7. PERSPECTIVESBeing the first such
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8. MATERIALS & METHODSThis chapter
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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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