Study of Electroconductive Polysilane with Nuclear Methods

1999 Fiscal Year Final Research Report Summary

• Project/Area Number: 09640688
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 機能・物性・材料
• Research Institution: KYOTO UNIVERSITY
• Principal Investigator: MATSUYAMA Tomochika Kyoto University, Research Reactor Institute, Professor, 原子炉実験所, 教授 (50027463)
• Co-Investigator(Kenkyū-buntansha): TAKAHASHI Toshiharu Kyoto University, Research Reactor Institute, Instructor, 原子炉実験所, 助手 (00273532)
• Project Period (FY): 1997 – 1999
• Keywords: Polysilane / Poly(methylphenylsilane) / Poly(di-n-hexylsilane) / Branchedpolysilane / Impurity analysis / Effect of γ-rays / Doping with iodine / Electrical conductivity

Research Abstract

1. Usually electroconductive polysilanes contain Na and Cl as impurity. Purification of them was attempted with distilled water, because their intrinsic properties are considered to be sensitive to the presence of impurities. It was confirmed that Na and C1 in the form of NaC1 is eliminated satisfactorily by three times washing of the polymers. It was also confirmed that the C1 end group in the polymers needs different methods to be removed from them.
2. The effect of γ-rays on polysilane was examined with poly(methylphenylsilane)(1)and poly(di-n-hexylsilane)(2)in solid state. It was found that the main chain scission occurs randomly in both polymers and its efficiency is low and high for 1 and 2, respectively. The low efficiency for 1 is ascribed to the pheny1 group in 1, where the phenyl group plays a protective role against the main chain scission. This phenomenon resembles the one known in polymers with carbine chain. It was also found that oxygen accelerates the main chain scission in both polymers during γ-irradiation.
3. It is proposed in polysilane that the electrical conductivity becomes larger by the formation of 3-dimensional paths through which carrier moves. To examine this proposal branched polymer, poly([methy1phenylsilane]ィイD2mィエD2-CO-[PHENYLSIYNE]ィイD2nィエD2), was prepared by controlling n=1-m, where 3-dimensional paths increase with increasing n since the polymer of n=0 is a linearchain and that of n=1 has a 3-dimensional network structure. When the polymers of various n were doped with iodine, any marked difference was not observed in their electrical conductivity reached finally. This result is explained as follows : cross-linking took place in the 1-dimensional component during iodine-doping and each branched polymer varied into a similar network polymer such as the polymer of n=1.