Synthesis and Characterization of Conductive Polyvinyl Alcohol/Gelatin Hydrogel

Hydrogels are being increasingly used in biomedical applications, such as biosensors and wearable skin sensors. However, conventional sensors made from metals and semiconductors are expensive and uncomfortable for patients due to their rigid shape. This research aimed to develop a cost-effective and flexible conductive hydrogel by synthesizing polyvinyl-alcohol (PVA) and gelatin hydrogel immersed in different concentrations of ammonium sulfate. The study examined the chemical functionalities, morphology, conductivity, and wettability of hydrogel. Physical crosslinking through freeze–thaw cycles was employed to synthesize the hydrogels, and different concentrations of ammonium sulfate (20 wt.%, 30 wt.%, and 40 wt.%) were used to achieve conductivity. The Fourier transform infrared spectroscopy (FTIR) analysis showed the interaction of O–H stretching at the range 3531–3008 cm−1 which referred to gelatin-based composition of O–H groups of glycerol. Furthermore, the peak at 1410 cm−1 stretching vibration indicates the presence of the crystalline region in PVA. From scanning electron microscopy (SEM) analysis the hydrogels appeared wrinkled and dense surfaces which affect the rate of absorbance. The hydrogel immersed in 30 wt.% ammonium sulfate exhibited the best conductivity with an average of 0.03μS/cm. The wettability analysis showed all samples possess hydrophilic properties as the average value of contact angles is less than 90° which is crucial for wound healing process. In conclusion, PVA/gelatin hydrogels with excellent conductivity possess significant potential for various biomedical applications.