Gamma Radiation-Initiated Miniemulsion Polymerization of Multifunctional Polymer Nanocapsule with Heat Storage, Antibacterial, and UV-Activated Coating Properties
Abstract
Multifunctional nanocapsules containing phase change materials for antibacterial and UV-activated coating were prepared by gamma radiation-initiated miniemulsion polymerization using polymerizable surfactant for the first time. Firstly, the polymerizable surfactant, poly(2-methacryloyloxy dodecyl dimethyl ammonium chloride-4-methacryloyloxy benzophenone)-block-polymethyl methacrylate-iodide (P(QAC12-BP)-b-PMMA-I), containing both quaternary ammonium and benzophenone groups, was synthesized by solution iodine transfer polymerization (solution ITP). After that, gamma irradiation-initiated miniemulsion polymerization of methyl methacrylate (MMA) and divinyl benzene (DVB) as a shell and octadecane as a core (P(MMA-DVB)/OD) was prepared using P(QAC12-BP)-b-PMMA-I as polymerizable surfactant. The hydroxy radicals in the continuous aqueous phase initiated from gramma radiation were added with monomer and grew to be surface-active or z-mer, which enters the monomer droplet stabilized by P(QAC12-BP)-b-PMMA-I chains. In the final, P(MMA-DVB)/OD nanocapsules, anchoring P(QAC12-BP)-b-PMMA-I chains on the surface were obtained. The polymerization smoothly proceeded and reached high conversion (≥ 90 %) within only 1.5 h. The obtained emulsion has high colloidal stability without coagulation. The polymer nanocapsules were spherical with a size of about 180 nm and a high positive charge (> +70 mV). Because of the particle surface containing QAC12 and BP segments, the polymer particles can be coated on fabrics with a covalent bond based on UV-activated via BP group, whereas they have a high potential for antibacterial activity due to presenting QAC12. The obtained polymer emulsion can be used as a spray-based heat storage coating with antibacterial properties.