Thermoresponsive Microgels with High Loading of Zwitterions Exhibiting Superior Performance: A Macromonomer Approach

Abstract

AbstractIn this investigation, the synthesis of temperature‐responsive microgels containing high content of zwitterionic poly(phosphorylcholine) (PMPC) is reported. High loadings of polyzwitterionic chains are achieved by using PMPC‐based “macromonomers,” which are synthesized via a three‐step reaction process. The first step involves synthesis of PMPC homopolymers via reversible addition fragmentation transfer (RAFT) polymerization, followed by end‐group removal to generate reactive thiol groups, and last of all, introduction of polymerizable double bonds at the chain ends to provide PMPC‐based macromonomers. Macromonomers of three different molar masses (3000, 5000, and 10 000 g mol−1) are used in three different molar ratios (1, 3, and 5 mol%) to synthesize microgels using N‐vinylcaprolactam (NVCL) as the main co‐monomer in precipitation polymerization. It is observed that the extent of total incorporation of the zwitterionic moiety is a function of both the macromonomer molar mass as well as its molar fraction in the feed which has a direct effect on their solution properties such as hydrodynamic radii and volume phase transition temperature (VPTT). Interestingly, these microgels show unprecedented extent of protein‐repelling behavior owing to higher loading of zwitterionic moieties, what makes them interesting for the fabrication of protective coatings with anti‐fouling properties.