Abstract
Cyclic polymers are a class of polymers that feature endless topology,and the synthesis of cyclic poly-mers has attracted the attention of many researchers.Herein,cyclic polymers were efficiently constructed by self-folding cyclization technique at high concentrations.Linear poly((oligo(ethylene glycol)acrylate)-co-(dodecyl acrylate))(P(OEGA-co-DDA))precursors with different ratios of hydrophilic and hydrophobic moieties were synthesized by reversible addition-fragmentation chain transfer(RAFT)polymerization us-ing a bifunctional chain transfer agent with two anthryl end groups.The amphiphilic linear precursors underwent the self-folding process to generate polymeric nanoparticles in water.By irradiating the aque-ous solution of the nanoparticles with 365 nm UV light,cyclic polymers were synthesized successfully via coupling of anthryl groups.The effects of the ratios of hydrophilic and hydrophobic moieties in linear P(OEGA-co-DDA)copolymers and polymer concentration on the purity of the obtained cyclic polymers were explored in detail via 1H nuclear magnetic resonance(1H NMR),dynamic light scattering(DLS),UV-visible(vis)analysis,three-detection size exclusion chromatography(TD-SEC)and transmission elec-tron microscopy(TEM).It was found that by adjusting the content of the hydrophilic segments in linear precursors,single chain polymeric nanoparticles(SCPNs)can be generated at high polymer concentra-tions.Therefore,cyclic polymers with high purity can be constructed efficiently.This method overcomes the limitation of traditional ring-closure method,which is typically conducted in highly dilute conditions,providing an efficient method for the scalable preparation of cyclic polymers.
基金项目
国家自然科学基金(22201276)
国家自然科学基金(22131010)
国家自然科学基金(52021002)
中央高校基本科研业务费专项(WK2060000012)
维普
万方数据