Reversible Photochromic Nanofiber Membrane Containing Comb-Like Poly(octadecyl acrylate) Nanoparticles Used for Ultraviolet Intensity Indicator

A novel reversible photo-responsive polyvinyl alcohol (PVA)/polyethylenimine (PEI) electrospinning nanofiber membrane (NFM), assembled with photochromic nanoparticles containing spiropyran, is herein presented and the water resistance, mechanical properties as well as photochromic properties are investigated systematically. Here, glutaraldehyde, which can undergo a cross-linking reaction with PVA/PEI, is selected as a cross-linker to enhance water resistance and mechanical behavior of the NFM. Photochromic polymer nanoparticles are prepared using octadecyl acrylate as polymer matrix monomer through miniemulsion polymerization. Effect factors of the whole preparation process such as the PVA/PEI mass ratio, the amount of emulsifier, and the amount of photochromic nanoparticles added are regulated to obtain the optimal experimental parameters. The surface morphology and microstructure, water resistance, and mechanical properties of NFMs are studied by thermal field emission scanning electron microscopy, static water contact angle tester, and tensile universal testing machine, respectively. Furthermore, UV-vis spectrophotometer is employed to investigate the photochromic performance and fatigue resistance of NFMs. Overall, analyses reveal that the reversible photo-responsive electrospinning NFM exhibit excellent photoresponsivity, photoreversibility, and fatigue resistance upon UV irradiation, thus showing promising application in the field of ultraviolet intensity indicator.