Vapor-based polymer gradients.

Chemical vapor deposition (CVD) co-polymerization was used to fabricate polymer coatings, which comprise of reactive surface composition gradients. Two functionalized derivatives of [2.2]paracyclophane were fed into a two-source CVD system at a 180 ° angle, then copolymerized and deposited as a polymer gradient. Infrared and X-ray photoelectron spectroscopy (XPS) confirmed the compositional changes within the bulk polymer and at the surface. By manipulating process parameters, gradients of tailored compositional slope can be deposited on a wide range of substrates. We also were able to selectively immobilize fluorescence-labeled ligands onto the reactive polymer gradients, making CVD-based gradient surfaces a flexible platform for fabricating biomolecular substrates.