Abstract
Biobased polylactide (PLA) films were modified with low reticulate polysiloxane gel acting as a scalable platform for the hydrophilization of polymeric film surface. PLA thin film was first coated with poly(methylhydrogenosiloxane) (PMHS) by sol-gel transition via condensation of diethoxymethylsilane (DH) and triethoxysilane (TH) using trifluoromethanesulfonic acid as catalyst. Then hydrosilylation of Si-H bonds in presence of Karstedt’s catalyst allowed the covalent grafting of hydrophilic alkene containing molecules, i.e. triethyleneglycol monomethyl allyl (TEGMEA) and a new zwitterionic allylcarboxybetaine (ACB) synthetized for the first time by quaternization of dimethyl allyl amine (DMAA) with β-propiolactone. PMHS coating on PLA film was evidenced by Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). Observation by atomic force microscopy (AFM) revealed a homogeneous coating with low roughness (RMS = 0.29 nm). The hydrophilicity of functionalized PLA films was determined by water contact angle (WCA) measurement using captive bubble method. A large increase in wettability properties was observed for both grafting with TEGMEA (WCA = 38°) and ACB (WCA = 42°) in comparison with native PLA film (WCA = 80°). Moreover, the biocompatibility and anti-fouling efficiency of functionalized PLA films was evaluated by protein adsorption, bacterial adhesion, and cytotoxicity tests. The results indicate that the grafting of the two types of hydrophilic compounds doesn’t affect the biocompatibility of PLA while significantly reducing protein adsorption and bacterial adhesion, thus showing the great potential of this surface functionalization strategy for applications in the medical field.