Enhancement of Fe(III) to electro-response of starch hydrogel

摘要

In order to prepare excellent electro-responsive natural hydrogels, in this paper, soluble starch with large amount of hydroxyl groups was selected as raw material. For exploring the enhancement to electro-response of starch hydrogel, starch-Fe(III) composite hydrogels were successfully obtained by a combination of Fe(III) into starch hydrogel in this paper. The composite hydrogels were prepared asA-hydrogels cured in the presence of electric field andB-hydrogels which cured without electric field. The storage modulus ofA-hydrogels andB-hydrogels was measured using a dynamic viscoelasticity spectrometer (DMA); the consequent modulus increment (Delta G = G(A)-G(B)) and modulus increment sensitivity (Delta G/G(B)) were analyzed for indicating electro-response of the hydrogels. The physical microstructure of the hydrogels was observed by scanning electron microscopy (SEM). Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA) were used to study the chemical constitution and structure. The results show that there is a coordinate bond between Fe(III) with -OH of starch which leads to a stronger three-dimensional network structure and higher thermal stability of the starch-Fe(III) hydrogel. What's more, the electro-response of the hydrogels can be affected according to the Fe(3+)concentration. When the Fe3+ concentration is 0.15 similar to 0.25 M under the electric field of 0.8 kV mm(-1), the starch-Fe(III) hydrogels have the strongest electro-response, the maximum value of modulus increment (Delta G) is 24 kPa, and the modulus increment sensitivity (Delta G/G(B)) is about 90%, far more than pure starch hydrogel.