Photochemical Immobilization of Polymers on a Surface: Controlling Film Thickness and Wettability

Abstract

In this manuscript, we demonstrate the control of film thickness and surface wettability in the photochemical immobilization of poly (vinyl alcohol) (PVA) to a self-assembled monolayer (SAM) containing a phthalimide chromophore. Surface attachment is characterized by ellipsometry and contact angle measurements. The wettability of the resulting films is shown to depend on the chemical composition of the polymer. The film thickness is shown to depend on the irradiation time and molecular weight of the polymer. Using a photomask, micropatterns of polymers can be grafted to the SAM. The photopatterned surface can be "developed" by coating with a thin layer of a mixture containing poly (styrene) (PS) and triphenylsulfonium triflate.

Optical control of alignment and patterning in an azobenzene liquid crystal photoresist

“…13 Methods that utilize light to pattern surface features are of particular interest because light provides a simple, clean and non-invasive stimulus for manipulating matter. 14,15 Traditional ultraviolet (UV) photolithographic based indirect subtractive LCP patterning may be possible in conjunction with plasma etching, however incorporating an appropriate mask material that can be both deposited and sacrificially removed without impacting the material quality or alignment is a challenge and this approach does not appear to have been presented in the literature. Direct UV photolithography of an LCP was demonstrated by Yamashita et al, 16 however the yield was limited and optimal crosslinking required elevated temperature.…”