Thermochromic Hybrid Nanoparticles Comprising a Tungsten-Doped Vanadium Dioxide Core and a Poly(N-isopropylacrylamide) Shell Structure

초록

Hybrid nanoparticles based on tungsten-doped vanadium dioxide (WxVO2) nanoparticles and poly(N-isopropylacrylamide) (PNIPAm) for thermochromic smart window applications were synthesized via silica layer formation using (3-mercaptopropyl)trimethoxysilane (MPTMS) followed by the surface-mediated free radical polymerization of PNIPAm, resulting in the aqueous dispersion of the hybrid nanoparticles. The metal-insulator transition of the WxVO2 core at around 28 °C and the lower critical solution temperature of PNIPAm at around 32 °C enable the aqueous dispersion of the hybrid nanoparticles to present an efficient thermochromicity depending on the temperature over a broad spectral range from visible to near-infrared light. The difference in the solar modulation was over 25%, while the luminous transmittance (Tlum) significantly decreased from 85% to 15% with increasing WxVO2 composition in the hybrids. Our results suggest that the hybridization of WxVO2 and PNIPAm is a potential methodology for preparing efficient thermochromic materials

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