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Rubner, 1995), and charge density(Schoeler, Kumaraswamy, & Caruso, 2002). Repetitive deposition steps provide a precise control over the total thickness of the layers in the range from a few angstroms up to a few micrometers. The thickness increment after each deposition is referred to as a growth rate which is dictated by polyelectrolyte geometry, surface charges, and solution parameters(Decher, 1997). Some of the most widely used polyelectrolytes are sodium poly(styrene sulfonate), poly(diallyldimethyl-ammonium) chloride, poly(ethyleneimine), poly(allylamine), poly(vinyl sulfate), and poly(acrylic acid). Recent advances in LBL techniques, in the non-conductive area, have demonstrated the possibility of templating multilayers onto 3D scale substrates. Caruso et al. (Caruso, Caruso, & Mohwald, 1998) deposited LBL films onto a colloidal core. Subsequent removal of the core resulted in a thin-film shell. Roy et al. (Roy, et al., 2006) deposited LBL films onto a fully interconnected porous PLLA surface and the subsequent removal of PLLA resulted in a 3D object comprised of a vast nanosheath network of, high surface area and the highest void volume ever reported for a polymeric substrate. Rubner et al, (Cheung, et al., 1997; Fou & Rubner, 2002) were the first to apply the LbL technique in the field of electronically conductive polymers to construct PSS/PANI bilayers onto thin films in order to prepare a conductive device. Important advances have been made in this area by employing various conjugated polymers such as polyaniline and polypyrrole(Kim et al., 2002; Liang, Cabarcos, Allara, & Wang, 2004; Ram, Salerno, Adami, Faraci, & Nicolini, 1999). Ferreira et al.(Ferreira, et al., 1994) found that the solubility of PANI in an organic media such as dimethylacetamide(DMA) is much higher than that in water. A solution of doped polyaniline generally makes it more difficult to achieve the spontaneous adsorption of polyaniline chains onto a variety hydrophilic and hydrophobic surfaces(Cheung, et al., 1997). The presence of salt in the solutions has a subtle effect. Generally, it screens the monomer-monomer repulsive interactions, leading to enhancement of adsorption(Dautzenberg et al., 1994). Salt can play different roles in polyelectrolyte multilayer(PEM) formation and function, such as controlling the thickness increment of polyelectrolytes, the permeability(Harris & Bruening, 2000), and the stability(Dubas & Schlenoff, 2001b) of the multilayer. Most of the work published so far has revealed an increase in conductivity with an increase of the number of adsorbed PSS/PANI bilayers by measurement of electrical conductivity of LbL films deposited on a flat surface(Braga, et al., 2008; Paloheimo, et al., 1995). In most cases conductivity measured by 140
four-point probe increases continuously with addition of layers until a saturation plateau is reached around the 13 th bilayer or 25 th layer. The principal objective of this work is to prepare a novel 3D porous polymeric conductive device, prepared via the LbL deposition of a conductive polyelectrolyte onto a 3D substrate of fully interconnected porosity generated from a co-continuous polymer blend. The work will involve the preparation of the blends and control of the phase size. Annealing of the cocontinuous structure, followed by extraction of the porogen phases will be examined with a view to generating an ultra-low surface area, yet fully interconnected, porous material. Layer-by-layer adsorption of PSS/PANI onto the internal surface of the porous device will be carried out and details such as the growth rate and rate of adsorption and desorption of the polyelectrolytes will be examined. Finally the conductivity will be measured in order to examine the potential of the developed devices. 5.3 Experimental Methods 5.3.1 Materials Commercial homopolymers were used in this study to prepare the conductive substrate. Poly(methyl-methacrylate) powder of Mw=12000 was obtained from Aldrich. High-density polyethylene, HDPE with a molecular weight of Mw=79000 was obtained from Petromont and polystyrene, PS with Mw=290000 was purchased from Dow Chemical. Polyvinylidene fluoride was obtained from Arkema. The polyelectrolytes used were polyaniline with Mw=20000 supplied by Aldrich as a polycation and poly(sodium 4-styrenesulfonate), Mw=70000 purchased from Sigma-Aldrich as polyanion. Densities in the melt states were determined via a fully automated PVT(pressure-volume-temperature) equipment supplied by Thermoelectron. Volume variation at controlled temperatures and pressures were determined. Some of the characteristic properties of the homopolymers are reported in Table 5-1. Table 5-1. Characteristic Properties of Homopolymers 141
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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
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2.3.1.2.1 Polyaniline One of the mo
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CoPA/LLDPE/PANI blend and a poor-qu
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Narkis and co-workers extended and
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Figure 2-31: Conductivity of PVDF/P
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organic thin films, a novel and str
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on the topic have been reported in
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succeeded in creating thin films wi
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Addition of salt to the solution of
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different from that of linear homop
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Figure 2-39. Macromolecule with a)
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polyanion such as hyaluronan (HA)(P
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2.4.1.1.7 Effect of Salt on Multila
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2.4.1.1.8 Overcompensation of the M
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important factors determining the g
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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 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: thermodynamic explanation to predic
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
Page 207 and 208: A relationship between macropore si
Page 209 and 210: close together. It is interesting t
Page 211 and 212: Figure 5-9. Mass increase (%) indic
Page 213 and 214: In this work the conductance of the
Page 215 and 216: deposited PANI layers increases unt
Page 217 and 218: (52) Guo, H. F.; Packirisamy, S.; G
Page 219 and 220: 6.2 Introduction It is well-known t
Page 221 and 222: modified version of Harkins theory(
Page 223 and 224: 6.3 Experimental 6.3.1 Materials Co
Page 225 and 226: Complex voscosity (Pa.s) 1,0E+04 1,
Page 227 and 228: 6.3.5.2 Focused Ion Beam (FIB) and
Page 229 and 230: a) c) b) d) e) f) PMMA PMMA HDPE HD
Page 231 and 232: y Harkins theory, PS will always si
Page 233 and 234: a) b) c) d) e) f) PS Figure 6-6. a)
Page 235 and 236: 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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