Combining reversible addition-fragmentation chain transfer polymerization and thiol-ene click reaction for application of core-shell structured VO2@polymer nanoparticles to smart window

Abstract

Vanadium dioxide (VO2) can be considered as one of the best candidates for thermochromic smart windows. However, there remain a few limitations that hinder its real application, such as poor stability, low solar modulation efficiency, and weak compatibility with organic polymer matrix. To solve the above-mentioned problems, core-shell structured VO2@PMMA-b-PHFBMA nanoparticles with excellent properties are prepared by a reversible addition-fragmentation chain transfer (RAFT) polymerization, combined with a thiol-ene click reaction. The F-containing polymer shell can effectively reduce the surface energy and stabilize the obtained VO2 nanoparticles. The durability and acid resistance of the VO2 nanoparticles are highly enhanced by the “shield protection” of CF chains, which also improves their compatibility with organic polymer matrix. In addition, PMMA-b-PHFBMA-b-PSPA copolymer chains with photochromic and hydrophobic properties are also prepared by the RAFT polymerization. Through a layer-by-layer coating technique, a PMMA-b-PHFBMA-b-PSPA thin layer can be coated onto a VO2@PMMA-b-PHFBMA/PVB thin layer as an energy-saving coating. The composite film is capable of modulating visible region and near-infrared region, achieving solar modulation efficiency (ΔTsol) up to 20.34%, which is highly promising application for smart windows.