Preparation and characterization of poly(N‐isopropylacrylamide‐co‐iron(5‐acrylamido‐1,10‐phenanthroline)) based electro‐responsive hydrogel

Abstract

Poly(N‐isopropylacrylamide‐co‐iron(5‐acrylamido‐1,10‐phenanthroline)) based electro‐responsive hydrogel is prepared by the radical polymerization of N‐isopropylacrylamide (NIPAAm), iron (5‐acrylamido‐1,10‐phenanthroline) and bis (1,10‐phenanthroline) (ferroin monomer), using 2,2‐azobisisobutyronitrile (AIBN) as initiator and N,N′‐methylenebisacrylamide (BIS) as cross‐linker. The structure of the hydrogel is characterized by Fourier transform infrared spectroscopy (FTIR). The impact of different contents of ferroin and cross‐linker on swelling properties, crosslinking degree, mechanical properties, and deformation properties of hydrogels are investigated, which indicates that the hydrogels containing ferroin are low voltage responsive. The hydrogel exhibits a deformation rate of 71.56% and a deformation speed of 2%/s at a voltage of 10 V when the ferroin content is 2.67%. The deformation rate and deformation speed of hydrogels increase with increasing voltage. Therefore, the deformation rate can reach 80.69%, and the deformation speed can reach 15.56%/s. The crosslinking degree increases with increasing BIS content in hydrogels, while leading to a reduction in swelling degree and swelling rate. Moreover, the elongation at break decreases first and then increases, the tensile strength and compressive strength increase. Furthermore, the minimum responsive voltage of hydrogels for deformation decreases, the deformation rate and deformation speed increase first and then decrease.