Forcing single-chain nanoparticle collapse through hydrophobic solvent interactions in comb copolymers

We introduce a novel synthetic strategy in which high molecular weight comb copolymers with aliphatic side chains can collapse into single-chain nanoparticles (SNCPs) via photodimerization of anthracene under ultraviolet (UV) irradiation. By deliberately selecting hydrophobic comonomers with disparate solvency, we demonstrated that we could control chain collapse. We attribute these results to the formation of pseudo-unimicellar structures, whereby polyisobutylene (PIB) side chains are preferentially solvated, thereby compressing anthracene moieties to form a denser crosslinked core. The control of hydrophobic interactions is a common occurrence in proteins and we believe that our approach can be further extended to achieve multi-compartment SCNPs whereby each section is responsible for a given function. We demonstrate that we can tune the chain collapse of comb copolymers into single-chain nanoparticles upon UV irradiation through solvency control.