Spectroscopic ellipsometry as a complementary tool to characterize coatings on PDMS for CE applications

Abstract

This paper describes the use of spectroscopic ellipsometry to investigate the adsorption process of model polyelectrolytes (PDDAC and PSS) to thin-films of PDMS. A description of the information collected by ellipsometry as well as complementary information obtained by atomic force microscopy and contact angle measurements is discussed. Upon identification of the driving forces and optimum experimental conditions required for the adsorption, multilayer constructs were fabricated (ranging from 1 to 20 nm in thickness) and used to evaluate their effect on the separation of phenolic compounds by capillary electrophoresis. According to the presented results, polyelectrolyte layers of approximately 10 nm thick provided the best conditions for the separation of the selected phenolic compounds.