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Polyimides are well known for their high thermal stability, chemical inertness, and their high electrical resistance. These properties make them ideal for use in the aerospace and electronics industries. Often polyimides are modified by coating or doping the films with metal species to change the surface or bulk properties of the polyimide. Usually this is done to create an electrically conductive surface layer. Previously, surface layers of metal and/or metal oxide on polyimide films have been made by homogeneously doping a poly(amide acid) solution with a metal complex and then thermally curing to 300°C. However, much of the dopant remains in the bulk of the films. Depending on the nature of the metal salt or complex, it has been postulated that lower polymer decomposition temperatures result if residual dopant remains in the bulk of the polymer. Deposition by infusion of the metal salt or complex was proposed as an alternative method for developing surface layers on polyimide films. The infusion processes attempted and the resulting films will be described and discussed. / Master of Science

Aniline Black, a polymer containing p-benzoquinodiimine groups, was synthesized chemically or electrochemically by the oxidation of aniline. The polymer salts showed the conductivity of 10⁻¹-10⁻³ ohm⁻¹cm⁻¹. Polymers containing anthroquinodiimine units were also prepared by polycondensations. The syntheses of model compounds containing p-benzoquinodiimine were attempted. Multiazobisphenol monomers were synthesized. 4,4'-(3,3'-Dimethyl-4,4'-biphenylenebisazo) bisphenol 7, 4,4'-[azobis(p-phenyleneazo)] bisphenol 8, and 4,4'-(2-methoxy-1,4-phenylenebisazo) bisphenol 10 displayed liquid crystal (l.c.) properties, while model derivatives of 7, 8, and 4,4'-(4,4'-stilbenebisazo) bisphenol 9 did likewise. Monomers and derivatives of 4-[(4-hydroxyphenyl)azo]-1-naphthol 5, and 4,4'- [oxybis(p-phenyleneazo)] bisphenol 6 showed no l.c. behavior. New thermotropic polyesters based on these multiazobisphenols were synthesized. Sebacates of 5, 6, 7, 8, and 10 showed l.c. behavior, while polymers based on isophthalic or 5-t-butylisophthalic acid did not do so. Polyformals were also synthesized from these momoners, only that of 4 showed weak l.c. behavior. The correlation between the structure of these polymers and their tractabilities, electrical properties, liquid crystal behaviors was studied. Polymers and copolymers containing p-azoarylene and p-azoxyarylene groups were synthesized by oxidative coupling of various aromatic diamines. Films were cast directly from the reaction mixtures or from the polymer solution. The films were n-doped by sodium naphthalide or p-doped by iodine. They showed electrical conductivities of 10⁻⁴ to 10⁻⁵ ohm⁻¹cm⁻¹. AB monomers containing dipolar p-phenyleneazo groups were synthesized: 4-(4-hydroxy-2-methoxyphenylazo) benzoic acid 21, 4-[4-(4-hydroxy-2-methoxyphenylazo)-2-methoxyphenylazo] benzoic acid 22, and 4-(4-hydroxy-2-methoxyphenylazo)-3-nitrobenzoic acid 23. The monomers were polymerized by direct polycondensations. The polyester synthesized from 21 formed a red, transparent film. A polymethacrylate containing dipolar p-phenyleneazo groups in the side chains was also prepared by the free radical polymerization of 1- [3-methoxy-4-(p-nitrophenylazo)-phenoxy] hexyl methacrylate 28.

In this work, using the idea of an electrically conducting "functional unit," monomers and polymers with possible electronic and electro-optic applications were synthesized. The synthesis and polymerizations were, in many cases, novel and non-trivial. Dithiafulvene (1,3-dithiole) and variations of this functional unit were synthesized and incorporated into new condensation polymers. Polyesters, polyamides and polyhydrazones were all successfully synthesized and could be cast into films. These new polymers might be applicable as processable conducting materials if compatible dopants are employed or by themselves in the area of third order non-linear optics. Using a (meth)acrylate backbone, a spacer group of six methylene units, and a phenyl-CO₂-phenyl mesogen, linked by an ester group to a strongly polar optically active center containing a methoxy group, three new novel monomers and polymers were designed to exhibit smectic C* liquid-crystal phases. The polymers exhibited liquid crystalline behavior as was shown in differential scanning calorimetry and optical microscopy. Further studies and investigations in the synthesis of pure (meth)acrylate esters and their homopolymers yielded surprising results with regard to the Schotten-Baumann reaction. Interestingly, the use of meth(acryloyl) chloride in this scheme leads to (meth)acrylic anhydride, which is not easily isolable from distillable products. This anhydride is responsible for gelation in the polymerization of glycolate esters, and cannot be removed by work-up with various nucleophiles without disrupting desired ester functions. An S(N)2 method is recommended in this work.

by Yeung Mei Ki. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 122-127). / Text in English; abstracts in English and Chinese. / by Yeung Mei Ki. / Abstract --- p.i / 論文摘要 --- p.iii / Acknowledgements --- p.iv / Table of Contents --- p.v / List of Figures --- p.viii / List of Tables --- p.xi / Abbreviations --- p.xii / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Polymer light emitting devides --- p.1 / Chapter 1.1.1 --- Development history of PLEDs --- p.3 / Chapter 1.1.2 --- Basic structure of the PLEDs --- p.4 / Chapter 1.1.3 --- Operation principle of the PLEDs --- p.7 / Chapter 1.1.4 --- Electroluminescent (EL) polymers --- p.9 / Chapter 1.2 --- Research motivation and aim of study --- p.11 / Chapter 1.3 --- Thesis outline --- p.16 / Chapter Chapter 2 --- Instrumentation / Chapter 2.1 --- Thermal analysis --- p.18 / Chapter 2.1.1 --- Thermogravimetry (TG) --- p.19 / Chapter 2.1.2 --- Differential scanning calorimetry (DSC) --- p.22 / Chapter 2.2 --- Spectroscopic analysis --- p.27 / Chapter 2.2.1 --- Fourier transform infrared spectroscopy (FTIR) --- p.27 / Chapter 2.2.2 --- X-ray photoelectron spectroscopy (XPS) --- p.32 / Chapter 2.2.3 --- Photoluminescence spectroscopy (PL) --- p.36 / Chapter Chapter 3 --- Experimental metods to charaterize the elimination of / Chapter 3.1 --- Introduction --- p.41 / Chapter 3.2 --- Synthesis of the PPV precursor polymer --- p.43 / Chapter 3.3 --- Average molecular weight of the PPV precursor --- p.46 / Chapter 3.4 --- Thermal elimination of the precursor polymer --- p.48 / Chapter 3.5 --- Thermal stability of the PPV precursor polymer --- p.50 / Chapter 3.5.1 --- Sample preparation --- p.50 / Chapter 3.5.2 --- Experimental --- p.51 / Chapter 3.5.3 --- Results and discussion --- p.52 / Chapter 3.6 --- Structural changes of the precursor polymer during elimination --- p.57 / Chapter 3.6.1 --- Sample preparation --- p.57 / Chapter 3.6.2 --- Experimental --- p.58 / Chapter 3.6.3 --- Results and discussion --- p.58 / Chapter 3.7 --- Chemical composition of the precursor polymer upon elimination --- p.67 / Chapter 3.7.1 --- Sample preparation --- p.67 / Chapter 3.7.2 --- Experimental --- p.67 / Chapter 3.7.3 --- Results and discussion --- p.68 / Chapter 3.8 --- Effect of the conjugation length of the polymer on photoluminescence --- p.74 / Chapter 3.8.1 --- Sample preparation --- p.76 / Chapter 3.8.2 --- Experimental --- p.78 / Chapter 3.8.3 --- Results and discussion --- p.79 / Chapter 3.9 --- Conclusions --- p.89 / Chapter Chapter 4 --- Experimental methods to characterize the water absorption by PEDOT:PSS / Chapter 4.1 --- Introduction --- p.90 / Chapter 4.2 --- Determination of the water content of PEDOT:PSS at different relative humidity using TG --- p.93 / Chapter 4.2.1 --- Experimental --- p.94 / Chapter 4.2.2 --- Results and discussion --- p.96 / Chapter 4.3 --- Determination of bounded water content of PEDOT:PSS at different RH by DSC --- p.98 / Chapter 4.3.1 --- Experimental --- p.98 / Chapter 4.3.2 --- Results and discussion --- p.100 / Chapter 4.4 --- Determination of bounded water content of PEDOT:PSS at different RH by FTIR --- p.108 / Chapter 4.4.1 --- Experimental --- p.109 / Chapter 4.4.2 --- Results and discussion --- p.112 / Chapter 4.5 --- Conclusions --- p.118 / Chapter Chapter 5 --- Conclusions --- p.120 / References --- p.122

Wang Yuhao = 利用X光电子谱和导电原子力显微镜对聚3, 4-乙烯二氧噻酚 : 聚苯磺酸改性的研究 / 王宇昊. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references. / Text in English; abstracts in English and Chinese. / Wang Yuhao = Li yong X guang dian zi pu he dao dian yuan zi li xian wei jing dui ju 3, 4-yi xi er yang sai fen : ju ben huang suan gai xing de yan jiu / Wang Yuhao. / Abstract --- p.ii / 論文摘要 --- p.iii / Acknowledgements --- p.iv / Table of Contents --- p.v / List of Figures --- p.ix / List of Tables --- p.xiii / Chapter CHAPTER 1 --- INTRODUCTION --- p.1 / Chapter 1.1 --- Review of conducting conjugated polymers --- p.1 / Chapter 1.1.1 --- Development of conjugated polymer --- p.1 / Chapter 1.1.2 --- Basic concepts in independent-electron theories of conducting conjugated polymers --- p.2 / Chapter 1.1.2.1 --- "Huckel model and its difficulty, the importance of election-phonon" --- p.2 / Chapter 1.1.2.2 --- The SSH model and dimerization --- p.3 / Chapter 1.1.2.3 --- "Charge carriers in conducting conjugated polymers: soliton, polaron and bipolaron" --- p.5 / Chapter 1.1.3 --- "Poly(3,4-ethylenedioxythiophene) or PEDT" --- p.5 / Chapter 1.1.4 --- Derivatives of PEDT --- p.6 / Chapter 1.1.5 --- Application of PEDT and its derivatives --- p.7 / Chapter 1.2 --- Polymeric light emitting diodes (PLED) --- p.7 / Chapter 1.2.1 --- Invention Polymeric light emitting diodes (PLED) --- p.7 / Chapter 1.2.2 --- Electric structure of PLEDs --- p.7 / Chapter 1.2.3 --- Transition from excitons to photons --- p.8 / Chapter 1.2.4 --- Controlling electron and hole injection --- p.8 / Chapter 1.2.5 --- Application of PEDT-PSS as hole transporting layer in PLED --- p.9 / Chapter 1.2.6 --- "Phase separating in PEDT-PSS blend, removing the PSS rich layer" --- p.9 / Chapter 1.3 --- Motivations of the thesis work --- p.10 / References --- p.10 / Chapter CHAPTER 2 --- INSTRUMENTATION --- p.27 / Chapter 2.1 --- X-ray Photoelectron Spectroscopy --- p.27 / Chapter 2.1.1 --- History of XPS techniques --- p.27 / Chapter 2.1.2 --- Physical Basis --- p.28 / Chapter 2.1.3 --- Chemical Shift of Binding Energy in XPS --- p.29 / Chapter 2.1.4 --- Binding Energy Referencing in XPS --- p.29 / Chapter 2.1.5 --- Sampling Depth of XPS --- p.30 / Chapter 2.1.6 --- Instrumental Setup of XPS --- p.30 / Chapter 2.2 --- Scanning Probe Microscopy --- p.31 / Chapter 2.2.1 --- Introduction --- p.31 / Chapter 2.2.2 --- Atomic Force Microscopy and Conductive Atomic Force Microscopy --- p.31 / Chapter 2.2.3 --- Instrumental Setup for Conductive AFM --- p.32 / Chapter 2.3 --- The Low Energy Ion Beam (LEIB) system at CUHK --- p.32 / Chapter 2.3.1 --- Introduction --- p.32 / Chapter 2.3.2 --- Principle --- p.33 / Chapter 2.3.3 --- Instrumentation Setup --- p.33 / References --- p.33 / Chapter CHAPTER 3 --- Effects of Ar+ bombardment at 500 and 100eV --- p.42 / Chapter 3.1 --- Introduction --- p.42 / Chapter 3.2 --- Sample Preparation --- p.42 / Chapter 3.3 --- Ar+ sputtering and XPS measurement of the sputtered sample. --- p.43 / Chapter 3.4 --- Results and Discussion --- p.44 / References --- p.49 / Chapter CHAPTER 4 --- Effects of annealing on PEDT-PSS thin films studied by XPS and AFM --- p.60 / Chapter 4.1 --- Introduction --- p.60 / Chapter 4.2 --- Sample Preparation --- p.60 / Chapter 4.3 --- XPS measurements and results --- p.61 / Chapter 4.3.1 --- XPS of C 1s core level of PEDT-PSS --- p.61 / Chapter 4.3.2 --- XPS of O 1s core level of PEDT-PSS --- p.62 / Chapter 4.3.3 --- XPS of S 2p core level of PEDT-PSS --- p.62 / Chapter 4.3.4 --- XPS of Valence Band of PEDT-PSS --- p.64 / Chapter 4.4 --- C-AFM measurements and results --- p.65 / Chapter 4.4.1 --- C-AFM measurements on PEDT-PSS --- p.65 / Chapter 4.5 --- Measurements and results about film insolubility and conductivity --- p.65 / Chapter 4.5.1 --- Insolubility measurements --- p.66 / Chapter 4.5.2 --- Conductivity measurements --- p.66 / Chapter 4.5.3 --- Results from the film insolubility and conductivity measurements --- p.66 / Chapter 4.6 --- Conclusion --- p.67 / References --- p.68 / Chapter CHAPTER 5 --- Effects of low energy proton bombardment of PEDT-PSS films studied by XPS and AFM --- p.90 / Chapter 5.1 --- Introduction --- p.90 / Chapter 5.2 --- XPS and c-AFM studies of PEDT-PSS films bombarded by H+ --- p.90 / Chapter 5.2.1 --- Sample preparation --- p.90 / Chapter 5.2.2 --- Results and discussion --- p.90 / Chapter 5.3 --- Conductivity measurements --- p.92 / Chapter 5.3.1 --- Sample preparation for conductivity measurements --- p.92 / Chapter 5.3.2 --- Results and discussion --- p.93 / Chapter 5.4 --- Conclusion --- p.93 / References --- p.93 / Chapter CHAPTER 6 --- Concluding Remarks and Future Works --- p.106 / Chapter 6.1 --- Concluding Remarks --- p.106 / Chapter 6.2 --- Future Work --- p.106 / Chapter APPENDIX --- The SSH model in describing polyacetylene --- p.108 / Chapter Part 1 --- Assumptions of the SSH model --- p.108 / Chapter Part 2 --- Bloch model and SSH model. --- p.113 / Reference --- p.117

Low-loss off-chip interconnects are required for energy-efficient communication in dense microprocessors. To meet these needs, air cavity parallel plate and microstrip lines with copper conductors were fabricated on an FR-4 epoxy-fiberglass substrate using conventional microelectronics manufacturing techniques. Copper transmission lines were separated by a composite dielectric of air and Avatrel 2000P and by a dielectric layer of air only. The composite dielectric lines were characterized to 10 GHz while the all air dielectric lines were characterized to 40 GHz. The transmission line structures showed loss as low 1.5 dB/cm at 40 GHz with an effective dielectric constant below 1.4. These novel structures show low loss in the dielectric due to the reduced relative permittivity and loss tangent introduced by the air cavity. Transmission line structures with a composite dielectric were built by coating the sacrificial polymer poly(propylene carbonate) (PPC) over a copper signal line, encapsulating with an overcoat polymer, electroplating a ground line, and decomposing PPC to form an air cavity. The signal and ground wires were separated by a layer of 15 µm of air and 20 µm of Avatrel 2000P. Air cavity formation reduced dielectric constant more than 30 percent and loss of less than 0.5 dB/cm was measured at 10 GHz. Residue from PPC decomposition was observed in the cavity of composite dielectric structures and the decomposition characteristics of PPC were evaluated to characterize the residue and understand its formation. Analysis of PPC decomposition based on molecular weight, molecular backbone structure, photoacid concentration and vapor pressure, casting solvent, and decomposition environment was performed using thermogravimetric analysis and extracting kinetic parameters. Novel interaction of copper and PPC was observed and characterized for the self-patterning of PPC on copper. Copper is dissolved from the surface during PPC spincoating and interacts with the polymer chains to improve stability. The improved thermal stability allows selective patterning of PPC on copper. Decomposition characteristics, residual metals analysis, and diffusion profile were analyzed. The unique interaction could simplify air-gap processing for transmission lines. Inorganic-organic hybrid polymers were characterized for use as overcoat materials. Curing characteristics of the monomers and mechanical properties of the polymer films were analyzed and compared with commercially available overcoat materials. The modulus and hardness of these polymers was too low for use as an air-gap overcoat, but may be valuable as a barrier layer for some applications. The knowledge gained from building transmission line structures with a composite dielectric, analyzing PPC decomposition, interaction with copper, and comparison of hybrid polymers with commercial overcoats was used to build air-gap structures with improved electrical design. The ground metal was separated from the signal only by air. The signal wire was supported from above using 60 µm of Avatrel 8000P as an overcoat. Structures showed loss of less than 1.5 dB/cm at 40 GHz, the lowest reported value for a fully encapsulated transmission line structure.

Polypyrrole is an electrochemically synthesized conductive polymer that has physical properties which impede efforts to develop structure-properties relationships. The extent of conjugation, as limited by the presence of structural disorders in the polymer, is important in determining its inherent conductivity. The extent of conjugation in thin electrochemically generated films of polypyrrole and poly-N-methylpyrrole has been examined with resonance Raman spectroscopy. The Raman experiment was performed within the electrochemical cell and does not suffer from exposure to the contaminants encountered when transfer techniques are employed. Electrochemically reduced films of polypyrrole exhibited intense resonance Raman spectra of the carbon-carbon stretching frequencies. The position of these bands is a function of the number of double bonds in conjugation. The conjugation length within the polymer chain was found to be between 3 and 4 rings for PP and slightly less in PNMP (2-3 rings). This is the first reported determination of the conjugation length in PP and PNMP. This data confirms the idea that PNMP is less conductive than PP due to reduced planarity within the chain, thus less conjugation. Reduced films of PP and PNMP yielded intense luminescence that disappeared upon oxidation. The luminescence is a broad featureless band that consumes the weakly enhanced Raman of PNMP. The intensity of the luminescence increased as the reduction potential increased and the highest intensities occurred at potentials far cathodic of the E₀ for the film. The explanation for this is still obscure but may involve either further reduction of highly luminescent segments or a decrease in the amount of quenching by solvent or counter-ion interactions with the luminescer. / Ph. D.