Abstract:
　　Grafting a layer of chains on a surface to form a polymer brush has been considered as an effective approach to make it antibiofouling (i.e., less adsorption of proteins). It has been proposed or generally believed that it is the hydration of such a polymer brush with a layer of immobile water molecules that avoids the protein adsorption. If this is the only reason, one should ask a number of questions, including 1) why not using a thin layer of easily prepared hydrogel instead of those grafted chains; and 2) why poly(ethylene glycol) (PEG) is more preferred than other water-soluble polymers in the developments of anti-biofouling materials. In this lecture, we will look the captioned question from another angle; namely, using the entropic elasticity instead of the protein-surface interaction (the enthalpy change).