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the existence of continuous microstructures with a high accuracy when the components are soluble in specific solvents. In this approach, the volumes of the components before and after extraction are measured by weighing the sample and converting the weight to volume (Equation 6-2). Equation 6-2 % Cocontinuity = ∑Vinitial − ∑ n n Vinitial and Vfinal are the volume of one component or present in the sample, before and after extraction, calculated by weighing the sample and converting it to the volume. The reported value is the average of %cocontinuity for several samples and the average error bar for high continuity levels is ± 5% and for low continuity levels is ± 3%. Cyclohexane was utilized as selective solvents for polystyrene and acetic acid for poly(methyl methacrylate). 6.3.5 Characterization of Phase Morphology 6.3.5.1 Microtoming and Scanning Electron Microscopy (SEM) The specimens were cut and microtomed under liquid nitrogen to a plane face using a microtome (Leica-Jung RM 2065) equipped with a glass knife and a cryochamber type (LN 21). After the appropriate treatment of the sample with selective solvents (acetic acid for PMMA and cyclohexane for PS) to remove one or both of the components, the sample surface was coated with a gold/palladium by plasma deposition. A JEOL JSM 840 scanning electron microscope, operated at a voltage of 10keV to 12keV, was used to obtain photomicrographs of the sample surface. ∑ n V initial V final 180
6.3.5.2 Focused Ion Beam (FIB) and Atomic Force Microscopy (AFM) After cryomicrotoming the specimens and coating them with a gold-palladium alloy, a Focused Ion Beam (FIB), Atomic Force Microscopy (AFM) technique was used to examine the HDPE/PS/PMMA blend. The surface of the samples was treated and etched using a Hitachi focused ion beam FIB-2000A operating a 30 keV gallium beam. FIB uses a focused beam of gallium ions which are accelerated to energies of 5-50 kiloelectronvolts. Using an electrostatic lens, the ion beam can be focused on a very small spot, resulting in a high resolution because of the small emitting area. In this work, a 0.8 nA beam current and a dwell time of 3 μs was applied in order to remove approximately 3-4 μm of the surface. Milling was carried out parallel to the observed surface. Since each polymer component has a different interaction with the gallium beam, this approach induces topological differences and hence increases the contrast between components(Virgilio, et al., 2005a). The milled surface of the specimen was then examined by a scanning probe microscope dimension (AFM) with a Nanoscope IIIa controller in topological mode. The atomic force microscope measures topography with a force probe. Silicon tips with spring constant of 40 N/m and a resonant frequency of around 300 kHz was employed. 6.4 Results and Discussion In ternary HDPE/PS/PMMA blends, the very high interfacial tension of PMMA and HDPE(γHDPE/PMMA = 8.6 mN/m) and the low interfacial tension of PS/PMMA(γPS/PMMA = 2.4 mN/m) and HDPE/PS(γHDPE/PS = 5.1 mN/m) results in a positive spreading coefficient of PS over PMMA (λPS/PMMA) with a value of 1.1 mN/m. The other two spreading coefficients are negative and are λPMMA/PS = -5.9 mN/m and λHDPE/PMMA = -11.3 mN/m. This predicts a complete wetting case with the development of a thermodynamically stable PS layer between the PE and PMMA as represented for a ternary 40/20/40 HDPE/PS/PMMA blend as shown in Figure 6-4. In Figure 6-4, the various phases can be clearly identified by the topographical heights induced by FIB etching and subsequently quantified by AFM analysis in the topographical mode. Previous works(Reignier & Favis, 2000, 2003a, 2003b; Reignier, et al., 2003) have shown several submorphologies of HDPE/PS/PMMA such as matrix/core-shell morphology and double-percolated 181
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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
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increasing the pH value due to a de
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CHAPTER 3 - ORGANIZATION OF THE ART
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discussed above, HDPE, PS, PMMA, an
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CHAPTER 4 - LOW PERCOLATION THRESHO
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or model which predicts where the p
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concentration threshold for the ons
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chemical and weathering resistance,
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Table 4-1. Material Characteristics
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filled with blend pellets. To facil
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4.3.6 Conductivity Measurements DC
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experimentally in this research gro
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a) b) c) d) Figure 4-4. Schematic i
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microstructure of the quaternary bl
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a) b) c) d) Figure 4-6. SEM microgr
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a) b) PVDF PS PMMA c) d) e) HDPE PS
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Uniform layers of PS and PMMA situa
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the concentration of HDPE is increa
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a) b) c) e) Figure 4-11. SEM microg
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melt-processable and contains 25 wt
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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
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: Complex voscosity (Pa.s) 1,0E+04 1,
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 :
Page 237 and 238: 6.4.6 Continuity, Co-continuity, an
Page 239 and 240: c) V III II I VII I IV VI Figure 6-
Page 241 and 242: Continuity Scheme (a) Figure 6-10.
Page 243 and 244: Addition of a low concentration of
Page 245 and 246: Addition of small amounts of HDPE t
Page 247 and 248: icontinuous network with the HDPE.
Page 249 and 250: Three examples are shown in Figure
Page 251 and 252: (9) Mekhilef, N.; Verhoogt, H. Poly
Page 253 and 254: structures are formed due to the co
Page 255 and 256: CONCLUSION AND RECOMMENDATIONS In t
Page 257 and 258: REFERENCES A. K. Gupta, K. R. S. (1
Page 259 and 260: Caruso, F. (2003). Hollow Inorganic
Page 261 and 262: Domenech, S. C., Bortoluzzi, J. H.,
Page 263 and 264: Geuskens, G., Gielens, J. L., Geshe
Page 265 and 266: Hou, S., Harrell, C. C., Trofin, L.
Page 267 and 268: Krass, H., Papastavrou, G., & Kurth
Page 269 and 270: Macdiarmid, A. G., Jin-Chih, C., Ha
Page 271 and 272: Niziol, J., & Laska, J. (1999). Con
Page 273 and 274: Reghu, M., Yoon, C. O., Yang, C. Y.
Page 275 and 276: 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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