Surface modification of poly(ethylene-butyl acrylate) copolymers by microwave methodology and functionalization with 4-dimethylamino-N-(2-hydroxyethyl)-1,8-naphthalimide for acidity sensing

A new procedure was developed for functionalization in the solid phase by using microwave irradiation. Heterogeneous chemical modification of poly(ethylene-butyl acrylate) copolymer (EBA), hydrolysis, chlorination, and Schotten-Baumann reactions were monitored by attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. EBA was superficially functionalized by a previously synthesized fluorescent dye, 4-dimethylamino-N-(2-hydroxyethyl)-1,8-naphthalimide, and the depth profile of the functionalized polymer was determined by confocal Raman spectroscopy. The new functionalized materials were also evaluated as an acidic pH sensor by determining the change in the spectroscopic properties of absorption and fluorescence with pH of the solution and vapor phases. To improve the wettability of the EBA surface, oxygen plasma treatment was used and the response time of the solid sensor was analyzed.