Ultrathin Patterned Polymer Films on Surfaces Using Thiol−Ene Polymerizations

A simple and straightforward method for growing ultrathin, micropatterned polymer films on surfaces with precise thickness and spatial control is presented. A difunctional ene monomer and a difunctional thiol were photopolymerized on a surface terminated with thiol groups. The surface thiols participate in the polymerization, and a linear polymer is formed on the surface. Brush growth was spatially controlled by selectively polymerizing the monomers through a photomask, while the brush thickness was controlled by changing the ratio of thiol and ene monomers or by changing the monomer functionality. Further, the surface was passivated by attaching a patterned, cross-linked polymer film, which was then backfilled with another monomer, demonstrating the attachment of multiple functionalities on the surface in a controlled, photolithographically patternable manner. Thiol−ene polymerizations were carried out without an initiator and used to graft patterned, polymer films. The films were observed using scanning probe microscopy and characterized using ellipsometry.