Surface modification of poly(methyl methacrylate) by graft copolymerization

Abstract

AbstractGraft copolymerization was carried out onto a poly(methyl methacrylate) (PMMA) plate for surface modification. The following treatments were conducted to introduce peroxides into the PMMA surface prior to graft copolymerization: UV irradation, corona discharge, glow discharge, and ozone exposure. The static contact angle of the PMMA plate toward water decreased from 66° to 45 and 38° by the pre‐treatment with corona and glow discharge for 5 min, respectively, whereas the pre‐treatment with UV irradiation and ozone exposure caused no appreciable decrease in contact angle. When graft copolymerization of acrylamide (AAm) was carried out onto the pre‐treated PMMA plates by near‐UV light irradiation to decompose the peroxides in the presence of riboflavin, the contact angle further decreased to approximately 20° and the amount of AAm polymer grafted was 20–25 μg · cm−2 for the pre‐treatments with corona discharge, glow discharge and UV irradiation. However, graft copolymerization was practically not achieved onto the PMMA plate pre‐treated with ozone exposure. On the other hand, when graft copolymerization was performed at 50°C after degassing without UV irradiation, the amount of AAm polymer grafted was always less than 10 μg · cm‐2, independent of the pre‐treatment methods.