PIXE monitoring of diffusion during photo-polymerization

Patterned UV photo-polymerization is used to prepare polymer gratings from a mixture of mono- and di-functional acrylate monomers. The difference in r eactivity and mobility of these two monomers induces a concentration gradie nt during the photo-polymerization process. Uniform illumination afterwards fixes the grating. Monomers with different easily detectable elements, e.g ., Cl, Br, Si, F, enable the observation of lateral variations of concentra tion in these gratings with PIXE and PIGE using a scanning ion probe of 3 M eV protons. In addition, backscattering spectrometry is applied to correct for lateral thickness variations. (C) 2000 Elsevier Science B.V. All rights reserved.