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After a theoretical determination of the order of all phases, controlling the composition of phases allows us to generate novel morphologies such as onion morphology and multi-percolated structures. SEM micrographs confirm onion morphology for a quaternary HDPE/PS/PMMA/ PVDF blend with a matrix of HDPE and PVDF droplets encapsulated by first-shell PMMA encapsulated by second-shell PS. Changing the composition of phases, controls the evolution of the morphology from an onion structure to a multi-percolated one. It illustrates that in a multipercolated structure, all phases are fully interconnected and interpenetrated. In order to quantitatively find the precise region of multi-percolation, solvent extraction followed by a gravimetric measurement was used to obtain the percent continuity of each phase. Addition of PANI to highly continuous quaternary blend of HDPE/PS/PMMA/PVDF demonstrates a quadruple-percolated morphology with the order of phases as HDPE/PS/PMMA/PVDF/PANI. As PANI situates as the inner phase, even at low concentration it is forced to spread between other percolated phases. In another part of the first paper, the effect of the addition of PS-co-PMMA to quinary HDPE/PS/PMMA/PVDF/PANI blend with a quadruple-percolated structure is studied. Addition of a compatibilizing agent of two adjacent phases (PS and PMMA) demonstrates phase reduction of PS and PMMA in the blend. Since all phases are assembled in a hierarchically ordered manner, reduction of the phase size of two layers forces the other assembled layers to decrease in size. The first paper evaluates the effect of the number of the phases in a multi-percolated structure. Ternary, quaternary, quinary, and 6-component blends containing 5% PANI are prepared. The results indicate that increasing the number of components reduces the conductivity percolation threshold of all phases including PANI due to geometrical restriction of the phases. In order to spread the PANI, at least four components in the multi-percolated structure are required. Addition of a further number of phases increases conductivity correspondent to continuity of PANI only slightly. In the second paper, through development of multi-percolated morphology associated with a layer-by-layer (LbL) approach, a novel 3D porous polymeric conducting device (PPCD) is generated. This technique allows for the percolation threshold concentration of polyaniline conductive polymer (PANI) to be reduced to values as low as 0.19%. A fully interconnected porous HDPE substrate with ultra low surface area is prepared by generating double- and triplepercolated systems followed by annealing and selective solvent extraction of phases. As 92
discussed above, HDPE, PS, PMMA, and PVDF components are shown to produce a multi- percolated structure with hierarchically ordered phases, since the interfacial tensions of the various pairs satisfy the positive conditions of the Harkins equation sets. Ternary blends and quaternary blends are prepared. After quiescent annealing, a substantial increase in the average phase size is observed. Selective solvent extraction of multi-percolated structures results in preparation of substrates with higher void volume. Hence, a fully interconnected porous HDPE substrate of low surface area is prepared by employing double- and triple-percolated morphology. The extra-large pores of HDPE substrates also facilitates the penetration of the polyaniline (PANI)/poly(styrene sulfonate) (PSS) solution inward to the interconnected porous area. Up to thirty-eight PSS and PANI layers are deposited on the internal surface of the 3dimensional porous polymeric substrate, revealing an inter-diffused network conformation. Microstructural information collected by SEM and AFM depicts a relatively thick polyelectrolyte multilayer as wide as 5.5 μm for 38 layers of PSS and PANI on the surface of the porous HDPE substrate with a void volume of 66%. The mass deposition profile of PANI/PSS as a function of layer numbers demonstrates an unusual non-linear growth with an oscillatory behavior. The oscillating deposition indicates that PSS and PANI polyelectrolytes diffuse in the previously deposited layers. Like chains make contact with other like chains, and consequently, an inter-diffused network of PANI and PSS is generated. Since salt is generally added in procedures involving LbL deposition, the effect of the addition of 1 molar NaCl salt to the PSS polyanion in the multilayer construction is studied. Conductivity measurements show that the percolation threshold of PANI in porous devices is achieved at a maximum of 8 layers. This corresponds to 0.19 wt.% PANI for a porous substrate made of 33% HDPE/33% PS/33% PVDF and 0.28 wt.% for a porous substrate generated from 33% HDPE/33% PMMA/33% PVDF. It is found that sample conductivity increases by increasing the number of deposited PSS/PANI layers until a conductivity saturation plateau is reached after 32 deposited layers. Compression of porous samples can be employed as another control parameter to achieve a wide range of conductivities in these conductive porous devices. In the last paper, ternary HDPE/PS/PMMA blends with various compositions of components represent a complete wetting case with the development of a thermodynamically stable PS layer between the HDPE and PMMA. Four thermodynamically stable sub-classes of morphologies exist for HDPE/PS/PMMA, depending on the composition of phases: a) matrix/core-shell 93
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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,
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where the parameter z is dependent
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“compatibilization” was suggest
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a) λ BC A and B are matrices, b) C
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Reignier & Favis, 2000, 2003a; Reig
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measure the interfacial tension of
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a) b) Figure 2-6. Dependence of the
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Omonov et al. found double percolat
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2.1.2.2.3 Effect of Composition on
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a) b) C B A c) Figure 2-12. SEM pho
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In the case where PS is the matrix,
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Posthuma de Boer, 1999) (Kumin & Ch
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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 and 116: on the topic have been reported in
Page 117 and 118: succeeded in creating thin films wi
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: CHAPTER 3 - ORGANIZATION OF THE ART
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
Page 167 and 168: the concentration of HDPE is increa
Page 169 and 170: a) b) c) e) Figure 4-11. SEM microg
Page 171 and 172: melt-processable and contains 25 wt
Page 173 and 174: One question that should be address
Page 175 and 176: Conductivity(S/cm) Ternary Blend 1,
Page 177 and 178: phase(PMMA), the concentration of P
Page 179 and 180: (6) Virgilio, N.; Desjardins, P.; L
Page 181 and 182: ONION MORPHOLOGY HDPE PVDF PS Contr
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Page 185 and 186: thermodynamic explanation to predic
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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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