Surface Modification of Nanoporous Poly(ϵ-caprolactone) Membrane with Poly(ethylene glycol) to Prevent Biofouling: Part II. Effects of Graft Density and Chain Length

Biofouling is a common problem in wastewater treatments and medical devices. It is important to find a strategy to prevent biofouling and surface modification. This study presents a novel approach to modifying the surface of nanoporous poly(ϵ-caprolactone) membrane with poly(ethylene glycol) (PEG) to prevent biofouling problems. Oxygen plasma and poly(ethylene glycol)-monoacrylates (PEGMAs) were utilized in the surface modification process. Mouse embryonic fibroblast was used as a model biofoulant. The effects of the density and length of PEG chains on surface properties and cell adhesion were investigated. Contact angle measurements and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectra illustrated that PEG can be successfully immobilized on the membrane surface. Membranes which were pre-treated with higher PEG concentrations can lead to higher grafting density and greater resistance against cell adhesion. The resistance against cell adhesion cannot be enhanced while the PEG concentration is higher than a certain point, i.e., 0.1 M. For different chain lengths, PEG(400)MA can provide higher resistance to cell adhesion than PEG(200)MA and PEG(1000)MA.