pH-Sensitive Hydrogel from Polyethylene Oxide and Acrylic acid by Gamma Radiation

Hydrogel as a good water absorbent has attracted great research interest. A series of hydrogel based on polyethylene oxide (PEO) and acrylic acid (AAc) was prepared by applying gamma radiation with variation in the concentration of acrylic acid. Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) were used to characterize the PEO/ AAc hydrogel. The properties of the prepared hydrogels such as gel content, swelling behavior, tensile strength, and pH sensitivity were evaluated. The formation of the hydrogels was confirmed from FTIR spectra. SEM images showed the inner porous structure of the hydrogels. The dose of gamma radiation was optimized to get a hydrogel with good swelling property and mechanical strength. The swelling ratio and gel content of the hydrogels were increased with increasing acrylic acid content. The pH of the solutions affected the swelling which indicated the pH-responsive property of the prepared hydrogels. Swelling of the prepared hydrogels in sodium chloride salt solutions decreased with increasing the ionic strength.