Antifreeze Glycolipid-Inspired Ice Recrystallization Inhibitors Based on End-Group Functionalized Poly(vinyl alcohol)

Poly(vinyl alcohol), PVA, is a molar mass-dependent ice recrystallization inhibitor (IRI), with larger polymers that are more active, similar to antifreeze glycoproteins. Attempts to modulate PVA's IRI activity by side-chain modification or assembly have given limited gains or even a loss of function. Here we take inspiration from antifreeze glycolipids by installing hydrophobic tails at the α-terminus of well-defined PVA derived from RAFT/MADIX photopolymerization, enabled by site-specific capping of the structurally ambiguous ω-end chains. Lower molar mass PVAs (<1000 g·mol^-1) were discovered to have enhanced IRI upon installation of the tails below 0.1 mM, which was more active than small-molecule IRIs of a similar MW. This unlocks new opportunities for IRIs at moderate molar masses and the potential to modulate activity via site-specific end-group chemistry.