Vapor-based synthesis and micropatterning of Janus thin films with distinct surface wettability and mechanical robustness

Polymeric Janus thin films were synthesized using a facile, one-step, vapor-based approach. The resultant films are comprised of two ultrathin surface layers of poly(1H,1H,2H,2H-perfluorodecyl acrylate) and poly(dimethyl amino ethyl methacrylate) hydrogel, covalently linked to a highly crosslinked bulk of poly(ethylene glycol diacrylate). Such an architecture allows distinct wetting behavior on the two surfaces while enabling the film integrity and mechanical robustness to be simultaneously achieved. Owing to the strong support from the crosslinked bulk, the Young's modulus and hardness of the Janus film were significantly improved compared with those of the polymers composing the two surface layers. The film is highly transparent across the visible light spectrum. The Janus film was further micropatterned using a templated vapor deposition method and transferred to nonplanar substrates.