An ultraviolet shielding hydrogel of P(NaSS-co-MPTC)/TiO2 was prepared by introducing TiO2 nanoparticles (TiO2 NPS) into polyampholyte matrix through photo-initiated radical copolymerization of cationic monomer of 3-(methacrylamide) propyltrimethylammonium chloride (MPTC) and anionic monomer of sodium 4-vinylbenzenesulfonate (NaSS) in the aqueous solution of sodium chloride (NaCl). FTIR, XPS, TEM, XRD, and SEM were used to characterize the morphology and structure of hydrogel of P(NaSS-co-MPTC)/TiO2. The result showed that anatase TiO2 NPS with the size about 15 ~ 20 nm were not just acted as ultraviolet shielding agent and general photo-initiator, they also could be crosslinked in polyampholyte matrix by hydrogen bonding between hydroxyl groups on the surface of TiO2 NPS and sulfonate groups on the polymer chains. Based on two kinds of reversible weak bonds of hydrogen bond and ionic bond, the P(NaSS-co-MPTC)/TiO2 hydrogel exhibited excellent mechanical properties and self-healing ability at ambient conditions, which will greatly increase its service life being a UV inhibitor.

A new polymeric hydrogel P(PVIS–AA) based on zwitterionic liquids (1-propyl-3-vinyl imidazole sulfonate) (PVIS) and acrylic acid (AA) was prepared by free-radical polymerization. The resulting three-dimensional (3D) networks can serve as nano-reactors for the production of small size and highly stable palladium nanoparticles by in situ reduction of PdCl62− with sodium borohydride (NaBH4) as a reducing agent. To get enough mechanical strength, ferric (Fe3+) was used to form the second crosslinking. The as-prepared hybrid hydrogel (P(PVIS–AA)/Pd@Fe3+) was successfully confirmed by means of Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), field emission scanning electron microscopy (FESEM), an electrical universal material testing machine, transmission electron microscopy (TEM) and thermogravimetric analysis (TGA), and then tested to catalyze the reduction of 4-nitrophenol. The catalytic results indicate that within 6 min, 4-nitrophenol with an initial concentration of 5 mM can be reduced completely, in addition, the mechanically strengthened P(PVIS–AA)/Pd@Fe3+ hydrogel shows excellent reusability for five successive cycles, with no appreciable decrease in the catalytic effects.