Stably dispersible P3HT/ZnO nanocomposites with tunable luminescence by in-situ hydrolysis and copolymerization of zinc methacrylate

In this paper, the copolymer shell with the internal hydrophobic polymethacrylate layer and the external hydrophilic poly(ethylene glycol) methyl ether groups was successfully bonded on the surface of ZnO nanocrystals through a simple sol-gel method, i.e., radical polymerization of zinc methacrylate (Zn(MA)2) and poly(ethylene glycol) methyl ether methacrylate (PEGMEMA) and hydrolysis. The prepared ZnO@poly(methacrylate-co-poly(ethylene glycol) methyl ether methacrylate) (ZnO@PPEGMA) nanocrystals showed good dispersion and smaller particle size, due to the presence of copolymer shell. The optical properties of ZnO@PPEGMA nanocrystals were characterized by ultraviolet-visible (UV-vis) spectroscopy and photoluminescence (PL) spectroscopy. The results indicated that the absorption edge and PL emission in the UV region of ZnO@PPEGMA nanocrystals appeared obvious blue-shift, due to the smaller particle size. Incorporation of ZnO@PPEGMA nanocrystals into poly(3-hexylthiophene) (P3HT) matrix, the dispersion of P3HT/ZnO@PPEGMA nanocomposites was greatly improved and the nanocomposites possessed excellent photoluminescence stability. Meanwhile, it was observed that the PL emission of P3HT/ZnO@PPEGMA nanocomposites was enhanced significantly, due to the presence of copolymer shell and the improvement of compatibility of ZnO@PPEGMA in the P3HT matrix. The results showed that the P3HT/ZnO@PPEGMA nanocomposites could be potential candidates for optical applications.