Preparation of single chain nanoparticles via photoinduced radical coupling process

Abstract

This contribution introduces a straightforward method for preparing well-defined polymeric nanoparticles using radical coupling process of ketyl moieties resulted from triplet excitation of pendant benzophenone groups. In the first step, poly(styrene-co-chloromethylstyrene) is synthesized by thermally initiated controlled radical copolymerization technique and subsequently, pendant chloride groups undergo post-modification with 4–hydroxybenzophenone. Achieved well-defined side–chain benzophenone containing copolymers generate ketyl radicals in the presence of excess hydrogen donor molecule upon UV-light irradiation and intramolecularly crosslinked nanoparticles are formed by radical coupling process in dilute regime. Resulting single chain nanoparticles and intermediates are characterized by 1H NMR, gel permeation chromatography, differential scanning calorimetry, UV–Vis spectrometry and electron microscopy techniques.