Polymerization catalyst laser-interference patterning.

The binding of molecular polymerization catalysts to solid supports, in the form of microporous particles or also flat substrates, has been extensively studied. 11 .] The primary aim is to gain control of the morphology of the polymer formed directly during polymerization. This approach can be convenient, for example, in saving additional processing steps if the polymer is formed directly in the desired particle size. For intractable, insoluble polymers not amenable to postpolymerization processing, it is a necessity to directly generate any desirable morphological features during polymerization. Despite these vast studies, a spatial resolution of catalysts on supports has rarely been achieved.l3-5] Such a spatial resolution could allow for the generation of more complex structures than homogeneously composed polymer particles or films. Such structures are obviously of interest from many different viewpoints, and a multitude of noncatalytic routes for their preparation have been developed.l613] Desirable features of a method generating a spatially resolved catalyst pattern are precision, rapidity, efficiency, and a generic nature. We report herein an approach employing pulsed laser-interference lithography of a coordination polymerization catalyst. Coherent laser light in the UVlVis range enables utilization of standard laser optics for the patterning process, and the period can be varied over a wide range through the angles of the incident laser beams.114] We chose the generation of polyacetylene as an example, as it is the prototype of a conjugated, conductive polymer and it is also well known for its notorious postpolymerization unprocessability.[15] As a catalyst precursor, a mixture of Pd(OAch and 1,3bis( di-tert-butylphosphino )propane was employed.15.11 .16] A methanol solution of this catalyst was spincoated on a silicon substrate. The resulting catalyst film was structured by an interference pattern by means of multiple nanosecond laser pulses, using the second harmonic of a Nd :YAG laser