Surface structure of poly(ethylene terephthalate) film grafted with poly(methacrylic acid)

Poly(methacrylic acid) (PMAAc) chains were immobilized onto the surface of poly(ethylene terephthalate) (PET) film by graft polymerization induced by light irradiation. Monomer conversion and density of grafted PMAAc increase d almost linearly with irradiation time and monomer concentration. The visc osity-average molecular weight of the tethered chains was roughly estimated as 1-3 X 10(6) when polymerization was carried out at 2-8 wt% monomer conc entrations for 2 h. The structure of the grafted surface was studied using atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). T he AFM image of the grafted surface was observed after staining with a cati onic dye to form the ion complex. The grafted polymer chains were found to form a cluster structure. New peaks appeared in the Cls and Ols XPS spectra of the PMAAc grafted surface and were assigned to the carboxylic group of PMAAc. The grafted surface had two peaks in the Cu2p XPS spectrum, when the surface was brought into contact with Cu ions. The chemical composition es timated from the XPS spectra of the grafted film suggested that the carboxy lic groups of PMAAc chains were linked to Cu ions through coordinate bondin g. (C) 2000 Elsevier Science Ltd. All rights reserved.