Effect of end-grafted PEG conformation on the hemocompatibility of poly(styrene-b-(ethylene-co-butylene)-b-styrene).

Polyethylene glycol (PEG) with one and two ends are grafted onto poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) via polydopamine (PDA) as a spacer to fabricate a hemocompatible surface. Linear and looped conformational PEGs modified SEBS are obtained, and the structures and compositions are confirmed by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). The hemocompatibility of SEBS are improved by the modification of PDA and PEG, and the proteins resistances of the looped PEG are superior to that of the linear PEG with the same grafting length and mass. Quartz crystal microbalance with dissipation illustrates that the protein resistance mechanism of looped PEG is because of the huge viscoelasticity and deformation. Furthermore, looped and linear PEGs with the same grafting density are grafted onto SEBS surface to clarify the superiority of the looped conformation. Protein adsorption of looped PEG with twice length of linear PEG shows lower adsorbed amount than the others. Therefore, immobilizing the looped conformation of PEG on SEBS surface is a versatile and efficient way to improve the hemocompatibility of SEBS.