Effect of pH, temperature, and electrolytes on swelling and release behaviors of PVA/AAm/GO based hydrogel composites

Hydrogels have been used in variety of applications, ranging from tissue engineering to drug delivery as controlled release material. In this study, the effect of temperature, pH and electrolytes solution medium on swelling and release behavior of polyvinyl alcohol (PVA). Acrylamide (AAM) and graphene oxide (GO) based hydrogel composites (HC) has been carefully investigated. The HC film were successfully prepared by solution mixing method at optimum volume ratio of PVA/AAM/GO of 5:10:4, respectively. FTIR spectroscopy, X-ray diffraction, and scanning electron microscopy (SEM) were used to describe HC’s structural morphology. In particular, the impact of environmental conditions on HC’s swelling behavior was on the variation of pH (2, 7 and 9), NaCl concentration (1%, 4%, 10%, 25% and 28%) and temperature (4 °C, 26 °C and 40 °C). The FTIR spectra confirmed the chemical interaction in the HC matrix between PVA, AAm, and GO, which occurs mainly through hydrogen bonding. The insertion of GO into polymer matrices notably modified the morphological structure of superabsorbent hydrogel composites, as ascertained by FTIR, SEM images and XRD patterns. The environmental condition remarkably affected the swelling behavior of HC, where the swelling behavior notably increased at pH 9 and temperature of 40°C conditions. The addition of NaCl also significantly enhanced the swelling capacity of HC up to 604% at optimum concentration of 25%. This result inferred that HC exhibited a great sensitivity toward pH, temperature, and electrolyte concentration.