Polymers containing bulky tetraphenylthiophene (TP) moieties were prepared by different coupling reactions. Firstly, 2,5-bis(4-bromophenyl)-3,4-diphenylthiophene (TP-Br) was coupled together by either NiCl2/PPh3 or n-BuLi to form polymers with TP as the repeat unit. The resulting polymers (PTP-NiCl2 and PTP-BuLi) are easily soluble in organic solvents and are photoluminescent (PL) materials (

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第20403号 / 工博第4340号 / 新制||工||1673(附属図書館) / 京都大学大学院工学研究科高分子化学専攻 / (主査)教授 澤本 光男, 教授 中條 善樹, 教授 赤木 和夫 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

Conjugated organic polymers have attracted immense interest for use in the active layer of photovoltaic cells, electroluminescent displays and diagnostic sensors. Precise control of the chemical structure of these conjugated materials is essential to achieve better device performance and certain structural aspects which have received minimal investigation include; the nature of the end groups, the precise control of the molecular weight and the formation of novel polymer topologies. Absolute control of these factors, in particular the end groups, has the potential to further tune the electro-optical properties, eliminate charge trapping and reactive sites, and facilitate block copolymer formation. The ring opening metathesis polymerisation of highly strained cyclophanediene monomers has proven to be an advantageous route to obtain soluble poly(p-phenylenevinylene)s (PPVs). In an extension of this previous work PPVs with both a pristine polymer backbone microstructure and a range of well-defined functional end groups have been prepared. These polymers exhibited excellent degrees of functionality, relatively narrow unimodal distributions and degrees of polymerisation much higher than those attainable by alternate routes. In particular the incorporation of an α-bromoester end group directly resulted in PPVs which were effective macroinitiators in the atom transfer radical polymerisation of methyl methacrylate. The diblock copolymers prepared by this route were isolated with narrow polydispersities, unimodal distributions and were free from homopolymer impurities. This method of preparing rod-b-coil diblock copolymers, where the properties of the two segments can readily be modified, provides access to materials which are of interest for both their self-assembly ability and for the development of a much required phase diagram in this area. Cyclic PPVs are of synthetic interest both for the absence of any end groups and for an infinitely long π-conjugated backbone, both of which are expected to contribute to unique electro-optical properties. The preparation of these target polymers was investigated by the ring expansion metathesis polymerisation of the cyclophanediene monomers. The formation of purely cyclic, low molecular weight PPVs was found to be highly dependent on both the reaction conditions used and the nature of the solubilising substituents. For example the preparation of purely cyclic PPVs with alkoxy side chains was unsuccessful, however the incorporation of alkyl side chains allowed for the successful isolation of the desired cyclic polymers.

Chemically identical but topologically different cyclic and linear polymers not only result in marked differences in dynamics, but also lead to unique transport properties of their blends, where cyclic polymers have chances to be threaded onto the linear polymers. This dissertation addresses the effect of ring architecture on dynamics using different time/length scale techniques: self-diffusion coefficients, NMR spin-spin relaxation time (T2) and bulk viscosity. In deuterated water, synthesized cyclic poly(oxyethylene) (CPOE) (400-1500 g/mol) diffused faster than corresponding linear POE (LPOE) and linear POE dimethyl ether (LPOEDE). However, the self-diffusion coefficients in melts were arranged in the following manner: LPOEDE > CPOE > LPOE, in excellent agreement with T2 and viscosity data, showing topological and chain end effects. Compared to LPOEDE, both CPOE and LPOE had higher activation energies for viscosity with less dependence on the molecular weight. In the blends of CPOE and LPOE for 900 and 1500 g/mol, the diffusion coefficient and viscosity in melts were higher and lower than the values predicted by a binary mixing rule, respectively. These deviations were attributed to the threading conformation, and the weight fraction of the threaded chains for 1500 g/mol was estimated by a three-term mixing rule. This threading conformation also appeared to influence such important bulk properties as the glass transition and spherulitic growth rate of the blends.