SURFACE OF GELATIN MODIFIED POLY（L—LACTIC ACID）FILM

In this paper, the surface structure of poly(L-lactic acid) (PLLA) film modified with gelatin was investigated. The PLLA film specimens were treated directly with aqueous alkali solution to provide their surfaces with carboxyl groups, so that these functional groups could become the reactive sites for gelatin immobilization. The functional groups of the PLLA films were identified by ATR-FTIR spectra and XPS spectra, the changes in surface morphology were observed by using environmental scanning electron microscopy (ESEM), and the hydrophilicity of modified PLLA films was examined by water contact angle measurement. Experimental results showed that the gelatin was immobilized with water-soluble carbodiimide (EDC) onto the PLLA film's surfaces, and the gelatin content on the polymer surface was related to carboxylic group formed in the controlled hydrolysis process. Rough surfaces caused by hydrolysis will predominantly favor the adhesion and growth of cell; and the hydrophilicity of these surfaces after the modification procedure is enhanced.