Polysulfobetaine
Polysulfobetaines are zwitterionic polymers that contain a positively charged quaternary ammonium and a negatively charged sulfonate group within one constitutional repeat unit. In recent years, polysulfobetaines have received increasing attention owing to their good biotolerance and ultralow-fouling behavior towards surfaces. These properties are mainly referred to a tightly bound hydration layer around each zwitterionic group, which effectively suppresses protein adsorption and thus, improves anti-fouling behavior. Therefore, polysulfobetaines have been typically employed as ultrafiltration membranes, blood-contacting devices, and drug delivery materials. The chemical structure of polysulfobetaines can be divided in several subgroups. Most widespread are amides of (meth)acrylic acid ('PSPP') or quaternary esters ('PSPE'). Also, compounds from poly(vinylpyridinium), poly(vinylimidazolium), or quaternary poly(pyrrolidinium) as well as zwitterionic ionenes, are often found. (Wikipedia).
