An investigation into surface modification of polyethylene films for hydrophilicity enhancement by catalytic ozonation

For a conventional polyethylene film, ozonation was conducted to increase its surface hydrophilicity. Copper sulfate was found effective as a catalyst in aqueous ozonation to increase the generation of surface peroxides significantly, which is the essential step for hydrophilicity enhancement. The percentage increase in peroxide generation could range from 41% to 58% by aqueous catalytic ozonation over its noncatalyzed gaseous counterpart. The optimum concentration of copper sulfate was found to be 0.05 g/L. After adding the catalyst, the length of ozonation could be significantly reduced so that the bulk mechanical strength of the films, represented by tensile strength, could be well preserved after ozonation. A novel kinetic model for the aqueous ozonation was proposed. This model was developed by combing the reaction mechanism of gaseous ozonation of polyethylene films with that of ozone self‐decomposition in water. The peroxide generation also increased with the applied ozone dose. The surface morphology and contact angle of the film were all examined before and after ozonation. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013