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dispersed phase (60/10/30 HDPE/PS/PMMA); b) tri-continuous (40/25/25 HDPE/PS/PMMA); c) bi-continuous/dispersed phase (50/25/25 HDPE/PS/PMMA); d) matrix/two separate dispersed phases (20/60/20). Solvent extraction/gravimetry is used to examine the extent of continuity of the components. Increasing the concentration of the core phase in the matrix/core-shell morphology results in the coalescence of core phases which leads to the formation of a tri- continuous morphology. Tri-continuous structures can be classified into two categories: type I and type II. The bi-continuous/dispersed phase morphology consists in a co-continuous structure for two phases with the third phase present as a dispersed phase. A triangular composition/morphology diagram comprised of various compositions of HDPE/PS/PMMA is prepared to better understand the composition dependence of the various morphological states for complete wetting and their inter-conversion. This diagram demonstrates the concentration regimes for various morphological regions. These regions are detected by a combination of both SEM and FIB-AFM and through the use of selective extraction/gravimetric analysis as a quantitative technique to detect inversion points. Triangular continuity plots are introduced to show the continuity of the PS and PMMA phases respectively. It is found that in a ternary blend, percolation threshold becomes a line due to simultaneously changing the concentration of the two other phases in blend. Two compositional lines, or schemes, across the 3-axes triangular diagram which traverse multiple morphological states, are selected to study the effect of the concentration of the inner (HDPE) and middle (PS) phases on the morphology of the middle phase and the effect of the composition of the inner phase (HDPE) and the outer phase (PMMA) on the morphology of the middle phase (PS). It is shown that extreme changes in the viscosity of the PMMA phase (L-PMMA and H- PMMA) in a PS/HDPE/PMMA blend of constant composition still results in morphological structures where the PS separates HDPE and PMMA. In both the L-PMMA case and the H- PMMA case, the morphological classification of the bi-continuous/dispersed PMMA phase is unchanged. It is found that the scale of the resulting morphological structures has been significantly modified by the viscosity of the PMMA, as the system attempts to respond to the dramatically reduced interfacial area of the H-PMMA droplets. It is also found that the composition, interfacial tension, and viscosity ratio play an important role in determining the phase size in ternary polymer blends. 94
CHAPTER 4 - LOW PERCOLATION THRESHOLD CONDUCTIVE DEVICE DERIVED FROM A FIVE-COMPONENT POLYMER BLEND 4.1 Abstract In this work we report on the preparation of a solid, 3D, low percolation threshold conductive device prepared through the control of multiple encapsulation and multiple percolation effects in a 5 component polymer blend system through melt processing. Conductive polyaniline (PANI) is situated in the core of the 5 component continuous system comprised of high-density polyethylene(HDPE), polystyrene(PS), poly(methyl methacrylate)(PMMA) and poly(vinylidene fluoride)(PVDF) and, in this fashion, its percolation threshold can be reduced to below 5%. The approach used here is thermodynamically controlled and is described by Harkins spreading theory. In this work the detailed morphology and continuity diagrams of binary, ternary, quaternary and finally quinary systems are progressively studied in order to systematically demonstrate the concentration regimes resulting in the formation of these novel multiple- encapsulated morphological structures. Initially, onion-type dispersed phase structures are prepared and it is shown that through the control of the composition of the inner and outer layers the morphology can be transformed to a hierarchical-self-assembled, multi-percolated structure. The influence of a copolymer on selected pairs in the encapsulated structure is also examined. The conductivity of the quinary blend system can be increased from 10 -15 S cm -1 (pure PE) to 10 - 5 S cm -1 at 5 % PANI and up to 10 -3 S cm -1 for 10% PANI. These are the highest conductivity values ever reported for these PANI concentrations in melt processed systems. 4.2 Introduction Over the last 30 years the polymer-polymer blending of conventional polymers has received significant attention since these materials can result in highly synergistic property sets. Although a vast number of studies have been devoted to the study of immiscible polymer blends and of the 95
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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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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 and 138: CHAPTER 3 - ORGANIZATION OF THE ART
Page 139: discussed above, HDPE, PS, PMMA, an
Page 143 and 144: or model which predicts where the p
Page 145 and 146: concentration threshold for the ons
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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
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
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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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