Effect of 2-(dimethylamino) Ethyl Methacrylate on Nanostructure and Properties of pH and Temperature Sensitive Cellulose-Based Hydrogels.

The novel double responsive cellulose/poly 2-(dimethylamino) ethyl methacrylate (PDMAEMA) hydrogel was synthesized via in situ free radical polymerization. The results from light transmittance measurements, scanning electron microscopy (SEM), mechanical property testing as well as swelling experiments demonstrated that DMAEMA played a significant impact on in hydrogel's nanostructure.With increasing DMAEMA concentration, the transparency of hydrogels dropped and texture became softer. The incorporation of relatively hard cellulose and increase in crosslink density significantly enhanced 3D network structure of hydrogel. The tensile strength, compression and bending capabilities of the composite responsive hydrogels were fine with the DMAEMA in a certain range. When the DMAEMA concentration increased to 6 g/g(cellulose), the mechanical strength decreased noticeably. An increase in DMAEMA concentration resulted in a faster initial swelling rate and higher equilibrium swelling ratio. Further, three-dimensional structure and increase of DMAEMA concentration can also improve pH and temperature response sensitivity of hydrogels. Thus, the mechanical, swelling and responsive properties of hydrogel could be adjusted by the DMAEMA and polymerization modes.