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The scaffold could offer a potential new treatment for sports injuries and other cartilage damage. Three dimensional (3D) modelling and analysis of the reconstruction of the specimens is required to facilitate the study of the porous subjects and also to control and produce the desirable structures. 1.2 Objectives Devices made from semiconductor materials such as radios and computers are the foundation of modern electronics. Semiconductor devices include the various types of transistors, solar cells, and many kinds of diodes, which work with different conductivity values in a range from 10 -8 to 10 -2 S Cm -1 . Controlling the conductivity and resistivity of materials for various applications is a challenging problem. Polyaniline (PANI) is popular for its ease of preparation, good level of electrical conductivity, and environmental stability. Green protonated emeraldine has a conductivity on a semiconductor level in the order of 10 0 S cm –1 . Although the conducting form of PANI has a good chemical stability combined with relatively high levels of electrical conductivity, PANI suffers from the common disadvantage of conducting polymers, which is poor processibility. For this reason, PANI is used as a filler in the preparation of conducting composites, and for the surface modification of microparticles, powders, fibers, textiles, membranes, and porous substrates, endowing them with new electrical, chemical, and surface properties. A proposed way to cope with the poor processibility of conducting polymers is the preparation of PANI colloids, but this technique is limited to special applications. Melt-processing of PANI was suggested by several groups(Haba, Segal, Narkis, Titelman, & Siegmann, 2000; Narkis et al., 2000a; Segal, Haba, Narkis, & Siegmann, 2001; Shacklette, Han, & Luly, 1993) to combine the desired properties of conventional polymers and PANI. They were not successful in controlling the morphology of the blend, and consequently were unable to reach a percolation threshold lower than 15%. Also, in those cases the percolation threshold area is narrow and a resistive blend is quickly converted to a conductive blend. Therefore, the conductivity value of the material is not controllable in the range of semi-conductivity. 6
On the other hand, a novel tri-continuous structure derived from HDPE/PS/PMMA double- percolated morphology was reported, with a percolation threshold of PS as low as 3%(Zhang, et al., 2007). Though this model is not usable for PANI due to its high surface tension and polarity, a similar way is sought to spread the PANI phase throughout the blend. Since the conductivity of the blend depends on the volume fraction of the conductive phase and its morphology, the conductivity value of a sample can be controlled by manipulating the structure of PANI and its possible pathways in the blend. As discussed, it is very important to obtain a material with the exact desired conductivity value for special applications. Also, it is important to prepare samples in 3D bulk and porous structures. Most of the other preparation techniques produce 2D samples. The main objective of this work is developing novel and complex morphologies for the preparation of highly controllable 3D conductive materials. The study will also analyse the relationship between control of the multi-component blend morphology and reduction of the percolation threshold of the conductive phase. 1.2.1 Specific objectives: • Understand and develop the morphology of ternary, quaternary, and quinary polymer blends with complete wetting structure; • Study the development of multi-percolated (double, triple,…) morphologies to obtain the lowest possible continuity and conductivity percolation threshold in ternary, quaternary, and quinary polymer blends; • Evaluate the potential of both melt-blending/solvent extraction/LbL and multi-processing techniques to reduce the conductivity percolation threshold of a conductive polymer with high surface tension and polarity; • Study the effect of interfacial modifier on the continuity and conductivity of multipercolated morphology in quaternary blends; 7
Page 1 and 2: © Sepehr Ravati, 2010. UNIVERSITÉ
Page 3 and 4: DEDICATED To my parents iii
Page 5 and 6: RÉSUMÉ Cette thèse présente, po
Page 7 and 8: devenir une structure hiérarchique
Page 9 and 10: ABSTRACT This thesis presents, for
Page 11 and 12: system can be increased from 10 -15
Page 13 and 14: CONDENSÉ EN FRANÇAIS Dans ce trav
Page 15 and 16: deuxième coquille de PS. Les phase
Page 17 and 18: structures à percolation multiple
Page 19 and 20: autre sous-type de morphologie dans
Page 21 and 22: TABLE OF CONTENTS DEDICATION.......
Page 23 and 24: xxiii 2.4.1.1.1 Charged Polymer Ads
Page 25 and 26: 5.3.4 Annealing Test ..............
Page 27 and 28: xxvii REFERENCES ..................
Page 29 and 30: LIST OF FIGURES xxix Figure 1-1. a)
Page 31 and 32: Figure 2-12. SEM photomicrograph of
Page 33 and 34: Figure 2-34. Schematic view of diff
Page 35 and 36: Figure 4-8. SEM micrographs of vari
Page 37 and 38: Figure 5-6. a),b) Scanning electron
Page 39 and 40: and c) triangular concentration dia
Page 41 and 42: n number of moles p concentration o
Page 43 and 44: AFM atomic force microscopy LIST OF
Page 45 and 46: PS-co-PMMA copolymer of PS and PMMA
Page 47 and 48: 1.1 Introduction CHAPTER 1 - INTROD
Page 49 and 50: Figure 1-2. Human heart, longitudin
Page 51: One of the applications for porous
Page 55 and 56: 2.1 Polymer Blends CHAPTER 2 - LITE
Page 57 and 58: Based on Sterling’s approximation
Page 59 and 60: Antonoff’s rule (Equation 2-13) i
Page 61 and 62: 2.1.2.1 Binary Polymer Blends 2.1.2
Page 63 and 64: Some other studies(Everaert, Aerts,
Page 65 and 66: where the parameter z is dependent
Page 67 and 68: “compatibilization” was suggest
Page 69 and 70: a) λ BC A and B are matrices, b) C
Page 71 and 72: Reignier & Favis, 2000, 2003a; Reig
Page 73 and 74: measure the interfacial tension of
Page 75 and 76: a) b) Figure 2-6. Dependence of the
Page 77 and 78: Omonov et al. found double percolat
Page 79 and 80: 2.1.2.2.3 Effect of Composition on
Page 81 and 82: a) b) C B A c) Figure 2-12. SEM pho
Page 83 and 84: In the case where PS is the matrix,
Page 85 and 86: Posthuma de Boer, 1999) (Kumin & Ch
Page 87 and 88: lattice, such as square lattice, wi
Page 89 and 90: magnetization, which is a function
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
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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
Page 111 and 112:
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
Page 137 and 138:
CHAPTER 3 - ORGANIZATION OF THE ART
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discussed above, HDPE, PS, PMMA, an
Page 141 and 142:
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
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Conductivity(S/cm) Ternary Blend 1,
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phase(PMMA), the concentration of P
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(6) Virgilio, N.; Desjardins, P.; L
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ONION MORPHOLOGY HDPE PVDF PS Contr
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work described above has focused on
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thermodynamic explanation to predic
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four-point probe increases continuo
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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
Page 229 and 230:
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
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
Page 277 and 278:
Utracki, L. A. (1991). On the visco
Page 279 and 280:
Yasuda, K., Armstrong, R., & Cohen,
Page 281 and 282:
literature has examined factors inf
Page 283 and 284:
(Reignier & Favis, 2000, 2003a; Rei
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Table A-1.2. Interfacial tensions a
Page 287 and 288:
acquisition of images with a very h
Page 289 and 290:
Table A-1.3. Continuity of the PMMA
Page 291 and 292:
(17) Reignier, J.; Favis, B. D., Ma
Page 293 and 294:
PANI. Theoretically, the extent of
Page 295 and 296:
Equation A-2.7 0( ) 0 1. 5 σ = σ
Page 297 and 298:
Cumulative Mass × 10 5 (g) dipping
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of PANI, and an increase in the con
Page 301 and 302:
Resistance(ohm) 1.0E+12 1.0E+11 1.0
Page 303 and 304:
esistance value. Samples containing
Page 305 and 306:
The results of resistance for PS/PE
Page 307 and 308:
Caruso, F., & Schuler, C. (2000). E
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