Facile optimization of grafted chain length on antifouling properties based on hyperbranched polyglycerol

Abstract

Surface-grafted polymer brushes for enhancing biofouling resistance are determined by both the grafting density and chain length of brush on the antifouling membrane surfaces. However, the relations and internal regularities between the arrangement of polymer brush and the permeability and antifouling properties remain unsolved. The accurate effect of chain length is lost on the biofouling resistance behaviors. Herein, antifouling membrane surfaces of hyperbranched polyglycerol (HPG) brushes are obtained via tuning the chain lengths of HPG brush. The wettability and proteins' static adsorption are dramatically improved with the increase of HPG chain lengths. The parameter of chain volume overlap is preliminarily involved to describe the spatial distribution of HPG brushes. Unexpectedly, we demonstrate that the chain length of HPG is critical and a medium-length HPG brush displays an emerging permeability by a dense enough chain volume overlap (Dv) of the HPG architecture. The biofouling resistance behaviors are optimized using the response surface methodology. As the HPG brush grafting density increased, a higher flux recovery regardless of the chain lengths is observed. Qualitative and quantitative assays of E. coli and S. aureus attachment further reveal the low fouling characteristics of hyperbranched membrane surfaces. A deeper understanding of how the chain length of polymer brushes impacts permeability and the anti-biofouling property provides general guidance on the effectiveness of grafted polymer brushes.