Poly(acrylic acid)-graft-poly(ethylene glycol) preparation and adsorption on polyelectrolyte multilayers (PEMs) for custom-made antiadhesive surfaces

摘要

In this study, we report on a simple and versatile method for PEG>lalion of surfaces which is applicable practically independent of the substrate material: a poly(acrylic acid)-graft-poly(ethylene glycol) (PAA-g-PEG) copolymer was synthesized with grafting ratios g in the range of g = 20 2 [acrylic acid (AA) monomers to PEG side chains] and adsorbed either on bare stainless steel or on stainless steel prccoatcd with different types of polyelectrolyte multilayers (PEMs) from aqueous solution. For PAA-g-PEG synthesis two principal routes were compared with respect to yield and control of g: the active ester roule using different carbodiimidc coupling agents and the route via polyfacrylic acid chloride) (PAA-CI). Measurements based on Fourier transform infrared spectro-scopy in attenuated total reflection mode (FTIR-ATR) showed that the adsorbed amount of PAA-g-PEG copolymer is in general drastically enhanced, compared to bare stainless steel as a substrate, when a suitable PEM is used as an inlerlayer. The amount was also found to be strongly dependent on the type of PliM and to increase with increasing thickness of the PEM interlayer. The stability of highly PEGylated PEMs and the influence of thermal crosslinking on stability were investigated by immersing the PEM-PEG samples for 1 week into 1 M NaCl solution at pH 4.5 and 0.15 M phosphate buffered saline (PBS) at pH 7.4, respectively.