Synthesis of VO2/Poly(MMA-co-dMEMUABr) Antimicrobial/Thermochromic Dual-functional Coating and Reactivity Ratios Study

Yixian Liu, The University of Western Ontario

Abstract

Antimicrobial/thermochromic dual-functional coatings were successfully synthesized via UV-curing. The quaternary ammonium compound (QAC) N,N-dimethyl-N-{2-[(2-methylprop-2-enoyl)oxy]ethyl}undecane-1-aminium bromide (dMEMUABr) was synthesized and copolymerized with methyl methacrylate (MMA) for antimicrobial properties. Vanadium oxide (VO₂) nanoparticles were evenly dispersed within the coating, providing thermochromic properties. The dual-functional coating showed high luminous transmittance (T_lum(25°C) =36.1 %) and solar energy modulation ( T_sol=5.8 %). 90.3 % of bacteria reduction was observed against Escherichia coli within 24 h contact. To further understand the sequence distribution of the copolymer poly(MMA-co-dMEMUABr), the reactivity ratios of MMA and dMEMUABr monomer were studied and compared under thermal and UV initiation copolymerization. In the non-polar solvent chloroform-d, the reactivity ratio of MMA (r_MMA=0.06-0.46) was found lower than that of dMEMUABr (r_dMEMUABr=6.64-11.51) under thermal copolymerization, which was found consistent for reactivity ratios under UV copolymerization (r_MMA=0.73-0.76, r_dMEMUABr=4.42-4.48). However, in the polar solvent DMSO-d₆, it showed the opposite tendency (r_MMA=1.65-1.73, r_dMEMUABr=0.24-0.32) attributed to solvent-dMEMUABr monomer interactions.