Multi-responsive hydrogel based on lotus root starch

• The lotus root starch-based hydrogel was successfully synthesized by free radical copolymerization.
• The morphology and pore structure of the hydrogel were clearly observed by Biomicroscope, which were different from the FESEM images.
• The swelling in CaCl2 and AlCl3 solutions/temperature (25 °C–65 °C) displayed the “overshooting effect” swelling-deswelling phenomenon.
• The hydrogel can rapidly response to various pH.
• The utilization of lotus root starch was enriched.

The lotus root starch-based hydrogel was synthesized by free radical copolymerization. Fourier Transform Infrared Spectroscopy (FTIR) demonstrated that the formation of target product. X-ray diffraction (XRD) analysis showed the change of the starch’s crystallization. The morphology and pore structure of the hydrogel were evaluated by Field Emission Scanning Electron Microscope (FESEM) and Biomicroscope. Thermogravimetric analysis revealed the better thermal stability of hydrogel. Furthermore, the swelling in CaCl2 and AlCl3 solutions/temperature (25 °C–65 °C) displayed the “overshooting effect” swelling-deswelling phenomenon with prolonging the swelling time. The hydrogel can rapidly response to various pH value as well.