A tough and fluorescent dual nanocomposite hydrogel based on SiO2@TiO2 core-shell nanoparticles

Abstract

A tough and fluorescent NC hydrogel was fabricated by introduction of SiO2@TiO2 core-shell structure nanoparticles (NPs) into polyacrylamide (PAAm)/Laponite nanocomposite (NC) hydrogel. The photoluminescent and mechanical properties of the resultant PAAm/Laponite/SiO2@TiO2 dual NC hydrogel were explored with respect to the shell thickness of SiO2@TiO2. The dual NC hydrogel emitted stable and bright blue photoluminescence (PL), when radiated at 350 nm. The emission wavelength was slightly shifted from 423 to 428 nm with the increasing of the shell thickness due to the surface interaction of SiO2@TiO2 NPs and polymers. Besides, the compressive strength and compressive fracture energy of the PAAm/Laponite/SiO2@TiO2 dual NC hydrogels were 7535.8 kPa and 5740.3 J/m2 which increased by 19 and 21%, respectively, relative to the MLS@T0 dual NC hydrogel. The tensile strength was 207.2 kPa at a strain of 730%. The dual crosslinking of SiO2@TiO2 NPs and Laponite, as well as the dual nanocomposite structure were responsible for the enhanced mechanical properties.