No abstract

A new polymer P containing anthrylene-bisacrylate subunits is presented which allows the preparation of spin-cast films of high optical and geometrical homogeneity.Upon irradiation of these films with UVlight, both a change in the optical thickness (= geometrical thickness d x refractive index n) and a decrease of the solubility can be induced due to photocrosslinking of the polymer chains.These features make the new polymer a promising material for both optical information storage and photolithography and/or for a possible combination of the two effects.

Trianthrylene compounds with film-forming capabilities were synthesized in a three-step procedure by means of transition-metal catalyzed Grignard and Suzuki coupling reactions. Upon UV exposure, photopolymerization of the model compound l,ll-di-(9-anthryl)undecane was observed in solution as well in the film due to [4+4] cycloaddition of the anthracene moieties. The soluble photopolymers were characterized by NMR spectroscopy and GPC analysis. As expected, irradiation of solutions of the trichromophoric hydrocarbons afforded crosslinked photoproducts which precipitated from solution. In the case of an analogous trianthryl derivative with tetraoxyethylene spacers, formation of a gel was observed due to cycloaddition ofthe anthracene groups.The film-forming capabilities of trianthryl compounds in conjunction with UV-induced photocrosslinking can be useful for photoresist applications and will be discussed in the following paper FI.

Films of oligoanthrylenes are readily available by spin coating. Upon UVexposure, the properties (refractive index, fluorescence and solubility) ofthese films are changed due to [4+4] cycloaddition of the anthracene groups.This behavior appears to be useful for information recording purposes, which is demonstrated by surface plasmon and fluorescence microscopy. Although complete photobleaching of the films is not possible, effective photocrosslinking occurs for trichromophoric systems affording relief textures after development in ethanol/methylene chloride mixtures (negative tone photoresist). Furthermore, the reversibility of the solid state photodimerization of the anthracene moieties is discussed.