Micropatterning Microscopic Charge Heterogeneity on Flat Surfaces for Studying the Interaction between Colloidal Particles and Heterogeneously Charged Surfaces

An effective technique for micropatterning microscopic chemical heterogeneity onto solid surfaces for studying colloid interaction with heterogeneously charged surfaces is presented. Charge heterogeneity is micropatterned onto glass surfaces by the chemical modification of specified surface regions with aminosilane. The deposition (adsorption) of colloidal particles onto the micropatterned glass surfaces, under well-controlled laminar flow conditions, is observed in real time using a stagnation point flow cell and an optical microscope with a CCD camera.