Synthesis of ultrathin films of polyacrylonitrile by photoinitiated polymerization from self-assembled monolayers on gold

We report the synthesis of grafted polyacrylonitrile (PAN) brushes from alkanethiolate self-assembled monolayers (SAMs) on gold. The SAM consists of a dithiol-AIBN initiator that can be activated at room temperature by irradiation at 300 nm. The polymerizations were performed in DMF and yielded PAN films with a maximum thickness of similar to45 nm and a root mean square roughness of 0.17 nm after Soxhlet extraction. The static water contact angle was 55degrees, and the films were thermally stable after annealing at 105 degreesC for 3 days. The film thickness increased by 12% after annealing. The polymer films were characterized by reflection absorption infrared spectroscopy, contact angle measurements, and ellipsometry.