Real-time laser sheet refraction to monitor in situ the heterogeneity of polymerization process on Teflon surface

Real-time laser sheet refraction (RT-LSR) was used to study the polymerizat ion kinetics of the hydrophilic monomer 2-acrylamido-2-methyl-1-propanesulf onic acid (AMPS) in aqueous solution and the heterogeneity of the polymeriz ation process on the surface of a Teflon substrate. The spatial distributio n of refractive index along the vertical direction in the polymer solution was obtained in real time from the deflection of refracted light during pol ymerization. It was found that the polymerization of AMPS in the aqueous so lution follows the first-order reaction mechanism. Inhomogeneous distributi on of refractive index in the interface region near the Teflon surface, whi ch results from the suppression of polymerization in the interface region, is also observed directly.