Polysilanes having oxyethylenic side chains, {CH3-Si-CH2CH2CH2O(CH2CH2O)mR1}n where (m = 0,1,2,3) and R1 = CH3 and C2H5, have been prepared. A polysilane of m = 3 and R = CH3 is soluble in alcohols, acetonitrile, and water. Surface tensions of these polysilanes are larger than those of the polysilanes ever reported. While dispersion component stays almost constant(ca. 30–40 dyn/cm), polar component increases with increasing oxygen atom numbers in the side chain. Copolymers also keep the high values of surface tension.

A rapidly cooled poly(dioctylsilane) (PDOS) is found to exhibit unprecedented thermochromic behavior showing λmax at 353 nm as the major absorption which is accompanied with a minor one at 375 nm. On heating, the absorption at 353 nm begins to decrease at 250 K and, then, the minor one does at 280 K. Similar temperature dependent behavior is observed in the X-ray powder diffraction around 2θ = 6° which is ascribable to inter-chain alignment. On heating diffraction at 2θ = 6.2° (d = 1.43 nm) disappears firstly, and then that at 6.4° (d = 1. 38 nm) is displaced by the diffraction at 5.8° (d = 1.52 nm).

A number of silicon compounds and aromatic compounds form particles under UV light or electron beam irradiation in the gas phase. Carbonyl compounds, halogen compounds and some aromatic compounds act as initiators for photo-induced particle formation of silicon compounds.