Molecular Design of Zwitterionic Polymer Interfaces: Searching for the Difference

The widespread occurrence of zwitterionic compounds in nature has incited their frequent use in designing biomimetic materials. Therefore, zwitterionic polymers are a thriving field. A particular interest for this particular polymer class has currently focused on their use in establishing neutral, low-fouling surfaces. After highlighting strategies to prepare model zwitterionic surfaces as well as those that are more suitable for practical purposes relying strongly on radical polymerization methods, we present recent efforts to diversify the structure of the hitherto quite limited variety of zwitterionic monomers and of the derived polymers. We identify key structural variables, consider their influence on essential properties such as overall hydrophilicity and long-term stability, and discuss promising targets for the synthesis of new variants.