Preparation and characterization of rapid temperature responsive cationic comb-type grafted POE-POP based hydrogel as prospective excellent actuators/sensors

Abstract

In this study, novel temperature and pH–sensitive comb-type grafted (CH) poly(oxyethylene) (POE)- poly(oxypropylene) (POP) based hydrogels were prepared via epoxy ring-opening reactions. The prepared hydrogels were characterized using Fourier-transform infrared (FTIR) and differential scanning calorimetry (DSC) techniques. The thermo- and pH- responsiveness of the hydrogels was investigated by swelling experiments at the temperature of 4–50 °C and pH 5.0, 7.4 and 10.0, respectively. The desirable performance of the hydrogels was tested following swelling and deswelling kinetics at 4 and 37 °C, respectively, for all investigated pH values. According to the obtained results, the maximum equilibrium swelling of the prepared comb-type hydrogel was determined at 4 °C and pH 5.0. Comparatively to normal-type (NH) hydrogels that have same the oxypropylene ratio with CH, temperature dependence of the prepared CH hydrogels depicted faster deswelling rate than NH with no significant difference in pH dependency. The in-vitro drug-release study of the prepared POE-POP based hydrogels was performed with the model drug neomycin when the environmental temperature was changed. The findings indicated that neomycin was released even faster than the NH hydrogel from the CH hydrogels. The current finding reveals the rapid response rate properties possessed by the synthesized novel comb-typed POE-POP hydrogel, which can broaden the development of smart sensors/actuators in tissue engineering and drug delivery systems.