LAUSR

Maintaining stable surface properties, such as wetting, remains a challenge for many applications of functional coatings. Here, this paper reports a study on the stability of the surface properties of polydivinylbenzene (PDVB). The PDVB thin films are synthesized via initiated chemical vapor deposition (iCVD). The decrease of receding water contact angles and increase of contact angle hysteresis of iCVD PDVB over time are found to be related with surface oxidation during air exposure. Fourier transform infrared and X-ray photoelectron spectroscopy reveal the generation carbonyl and epoxy groups and the consumption of pendant vinyl groups in the oxidation process. A modified first-order kinetic model describes the dynamic process, and the apparent reaction rate constant for the oxidation of iCVD PDVB is 0.0238–0.0294 h−1. In order to inhibit the oxidation and stabilize the wettability of iCVD PDVB, an in situ thermal annealing process is developed. This thermal treatment is effective in improving the cross-linking degree of iCVD PDVB, slowing down the rate of oxidation, and therefore significantly enhancing the long-term wettability. The advancing and receding contact angles of annealed iCVD PDVB are stable even after exposure to air for two months. The reported thermal annealing approach also improves the mechanical properties of iCVD PDVB.