Glow discharge electrolysis plasma induced synthesis of cellulose-based ionic hydrogels and their multiple response behaviors

Abstract

Novel ionic hydrogels were prepared successfully from cellulose in the NaOH/urea aqueous system by a glow discharge electrolysis plasma (GDEP) technique. The structure and morphology of the ionic hydrogels were characterized by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM), as well as by determination of swelling and stimuli responses to pH and salts. The results showed that the swelling behavior and the network structure of the ionic hydrogels could be controlled by changing discharge voltage or discharge time, whereas we obtained the maximum absorbency of 898 g g⁻¹ for distilled water at 570 V and 90 s. Shrinkage of the network hydrogels took place at higher or lower pH. Relative to the Na⁺ buffer solution, hydrogels were more sensitive to Zn²⁺ and Fe³⁺ buffer solutions and showed network shrinkage and lower swelling ratio. This work provided a new pathway for preparation of cellulose-based hydrogels with environmental friendliness, high water absorption capacity, and rapid and multiple responses to pH and ions, which may allow their use in the biomaterials area.