Investigation of the heat resistance, wettability and hemocompatibility of a polylactide membrane via surface crosslinking induced crystallization

Abstract

Polylactide (PLA) has attracted much attention as a sustainable and environmentally friendly material. However, the poor heat resistance restricts its potential application as a porous membrane. Herein, a PLA membrane with excellent heat resistance, hydrophilicity and hemocompatibility was developed via a surface crosslinking induced crystallization strategy, which involved two key reactions, namely, copolymerization of N-vinyl-2-pyrrolidone (NVP) and triethoxyvinylsilane (VTES) and the subsequent hydrolysis condensation on the surface of the PLA membrane. Attenuated total reflectance Fourier transform infrared spectra (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) were applied to analyse the surface chemistry and crystallization evolution, which confirmed that the P(VP-VTES) copolymer was hydrothermally crosslinked and induced the crystallization of the PLA membrane. The surface crystallization significantly improved the heat resistance and preserved membrane morphology, which was characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), and the dimension shrinkage. The modified PLA membrane with χ_c ∼ 37% remained almost unchanged dimensions and morphology even after annealing at 100 °C for 5 min. The improved hemocompatibility was verified by the prolonged clotting time and recalcification time, which was consistent with the enhanced hydrophilicity. All results showed that surface crosslinking induced crystallization strategy simultaneously improved the heat resistance and hemocompatibility, indicating a promising method for preparing robust and compatible PLA membranes.