Photopolymerization with microscale resolution: Influence of the physico-chemical and photonic parameters

This article is aimed at demonstrating that physicochemical parameters can be used to control the spatial extent (length, width, and shape) of polymer objects in view of micro- and nano-fabrication applications. In particular, we showed that oxygen quenching and internal filter effects could be turned to advantage to modulate the response of the material by controlling the threshold energy of polymerization and/or the shape of the light into the photopolymerizable medium. The experimental configuration used in this study is based on light-induced polymerization at the extremity of an optical fiber that produces polymer micro-objects after development. Spectroscopic approaches and polymerization threshold measurements were performed to quantitatively evaluate the influence of the physicochemical parameters on the micropatterning of photopolymerizable material. Interestingly, fluorescence that is usually regarded as a process competing with photopolymerization reaction, was used for controlling the fabrication process. By this means, it was possible to better understand the impact of a nonhomogeneous irradiation on photopolymerization process and thus, to tune the shape and the size of the final polymer objects. (C) 2008 Wiley Periodicals, Inc.