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The harmonic mean equation approach is a classic approach for estimating the interfacial tension of polymer pairs and has been used widely in a number of studies(Wu, 1982). It can be seen that, compared to other polymer pairs, mixtures with PANI result in exceptionally high interfacial tensions. It thus follows from spreading theory that PANI will not be driven to encapsulate other polymers in a multi-component blend, rather it will tend to be encapsulated by virtually every other polymer species. For example, in a ternary HDPE/PVDF/PANI blend, a positive spreading coefficient value of 7.3 mN/m for λPVDF/PANI predicts encapsulation of PANI by PVDF as confirmed in Figure 4-3b. In that figure, the voids left by the extracted PVDF can be clearly seen to show that PVDF formed an interlayer between HDPE and PANI. By increasing the number of components in a multi-percolated structure, the percolation threshold of all phases sharply decreases. Thus, a unique approach to achieve a low percolation threshold conductive PANI device would be to prepare a multiple percolated blend system with PANI as the innermost phase. In this work we will examine the progressive morphological development of highly continuous multi-component structures by first examining the development of multi-encapsulated ternary to quinary droplets which are referred to here as onion morphologies. Then, the required conditions for transformation of the onion morphology to continuous multi-percolated morphologies and the conductivity of those systems are examined. 4.4.2 Self-Assembled Onion Morphology and the Hierarchical Ordering of Phases Typically, in the literature, a core/shell morphology is used to describe a droplet comprised of one phase encapsulated by another single phase. Here, we use the term onion morphology, schematically shown in Figure 4-4, to describe a multi-phase, multi-encapsulated dispersed droplet structure. In other words, a polymeric droplet phase comprised of layers of different polymers assembled concentrically. Figure 4-4 shows schematically the progression from a matrix-droplet(Figure 4-4a) to a core/shell(Figure 4-4b) and finally two cases of onion morphology(Figures 4-4c and 4-4d). 110
a) b) c) d) Figure 4-4. Schematic illustration of various encapsulated structures, a) dispersed phase B in matrix A, b) core-shell morphology B/C in matrix A, c) quaternary onion morphology B/C/D in matrix A, and d) quinary onion morphology B/C/D/E in matrix A. The thermodynamic conditions to obtain such onion structures for a given n-component blend is that the spreading coefficients of each of three selected components out of n components should satisfy the complete wetting case in Harkins equation. At the same time, the order of phases in each selected ternary blend should be consistent with the order of the phases situated in the multi-blend. This implies that for a core/shell structure, as there are only three phases in the blend system, only one set of Harkins equation needs to be examined. In the case of a quaternary blend system with an onion structure, a combination of three out of four which is equal to four systems of Harkins equation should be evaluated. Finally in this study, ten systems of Harkins equation (equivalent to three out of five components) should be evaluated for a quinary blend system, which in the present work is comprised of HDPE, PS, PMMA, PVDF, and PANI. Both the interfacial tensions and the spreading coefficients for these ten binary pairs are shown in Tables 4-3 and Table 4-4, respectively. The first four ternary blends in Table 4-4 indicate that in a quaternary blend comprised of an HDPE matrix with PS, PMMA, and PANI, the order of components from outer to inner should be: HDPE|PS|PMMA|PVDF. Using the data from Tables 4-3 and 4-4 it is also predicted that various other quaternary mixtures should assemble hierarchically as follows: HDPE|PS|PMMA|PANI (see spreading coefficients 1,4,5 and 8 from Table 4-4); HDPE|PMMA|PVDF|PANI (spreading coefficients 3,5,7 and 10); HDPE|PS|PVDF|PANI 111
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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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lattice, such as square lattice, wi
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magnetization, which is a function
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Polymers have long been thought of
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epoxy as a function of nanotube wei
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Figure 2-19. Approaching the percol
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Figure 2-21. Transmission electron
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Figure 2-22: Dependence of PE conti
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Figure 2-24. Plot of the total numb
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chain provides the conductive path
Page 105 and 106: 2.3.1.2.1 Polyaniline One of the mo
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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 and 138: CHAPTER 3 - ORGANIZATION OF THE ART
Page 139 and 140: discussed above, HDPE, PS, PMMA, an
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: experimentally in this research gro
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
Page 183 and 184: work described above has focused on
Page 185 and 186: thermodynamic explanation to predic
Page 187 and 188: four-point probe increases continuo
Page 189 and 190: in the rheology tests were compress
Page 191 and 192: 5.3.6 Layer-by-Layer Deposition The
Page 193 and 194: prepare a polymer blend structure w
Page 195 and 196: a) b) c) Figure 5-3. Scanning elect
Page 197 and 198: spontaneously self-assembled. After
Page 199 and 200: a) b) c) d) e) f) g) h) Figure 5-5.
Page 201 and 202: Since the ultra-low surface area va
Page 203 and 204: c) a) b) Figure 5-6. a),b) Scanning
Page 205 and 206: 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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