Polysilane polymers bearing hydroxyalkyl or alkoxyalkyl groups form monolayers (L films) at an air-water interface. It is possible to transfer all of the L films to hydrophobic substituents to provide Langmuir-Blodgett films. Among these polymers, polpilanes having more than three alkyl carbons have provided oriented polpilane thin f i in which the silicon main chains align with each other in the direction parallel to the dipping direction of the substrates. The orientations were evaluated by their polarized W absorptions. The dichroic ratios increase when Ca2+ ions were added to the water. Polysilane films with alkoxyalkyl groups show abrupt thermochromic transitions, while polysilanes with hydroxyalkyl groups show no thermochromism.

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A likely mechanism of especially large photosensitization for a base-developable poly-(phenylhydrosilane) resist (1) in the presence of 3,3′,4,4′-tetra(tert-butylperoxycarbonyl)benzophenone (EA1) is discussed in terms of photolysis rates and dissolution rates. The increase in the photolysis rate occurs through photoinduced electron transfers from polysilanes to electron acceptors. The fluorescence quenching rate of 1 in the presence of EA1 is almost the same as that in the presence of benzophenone (EA2). However, EA1 does increase both photolysis rates and resist sensitivities, but EA2 does not. The difference between EA1 and EA2 is discussed in terms of back-electron transfer in order to explain the importance of the presence of peroxide moieties. In the case of EA2, photoinduced electron transfers as well as back-electron transfers occur. In case of EA1, the cleavage of peroxide bonds on the benzophenone moiety would effectively inhibit the back-electron transfer to the 1 radical cation. The same phenomena are observed for C-60. EA1 photodecomposes to form compounds bearing carboxylic acids which also facilitate the dissolution of photolysis products of 1 into basic aqueous solutions.

Poly(phenylhydrosilane) becomes soluble in a 2.38% tetramethylammoniumhydroxide aqueous solution after exposure to UV light. This is the first report that the polysilanes not bearing acidic groups can be developed with dilute basic aqueous solutions. Addition of 3,3′,4,4′‐tetra(t‐butylperoxycarbonyl)benzophenone increases the resist sensitivity. The reaction mechanism is as follows: PS1 photodecomposes to form silyl compounds having SiOH groups, which become soluble in an aqueous base solution, because these silane compounds bearing SiOHs are acidic. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 2355–2364, 1997