作者：Jingli Yang,?ab Shuang Liu,?ab Ying Xiao,b Guorong Gao,b Yuanna Sun,b Qingzhong Guo,a Jiangyu Wu*a a
关键字：responsive, hydrogel, nanocomposite, strength, toughness
论文来源：期刊
具体来源：J Mater Chem B
发表时间：2016年

Multi-responsive hydrogels with high strength have great significance for potential applications in smart

soft devices. However, it remains a challenge to incorporate multiple responsive moieties with energy

dissipation mechanisms. Herein, multi-responsive nanocomposite hydrogels with high compressive

strength and toughness were synthesized via in situ copolymerization of N-isopropylacrylamide (NIPAM)

and acryloyloxyethyltrimethyl ammonium chloride (DAC) in an aqueous dispersion of exfoliated LAPONITEs

RDS with a minute amount of N,N0-methylenebisacrylamide (MBAA) as a crosslinker. The combined use

of clay and MBAA is demonstrated to be favorable for the high strength and toughness, and helped in

avoiding precipitation of clay nanosheets, which otherwise occurred upon addition of cationic DAC.

The effect of the NIPAM/DAC molar ratio, MBAA and clay contents on the properties of the

hydrogels has been systematically investigated. Compression tests showed a compressive strength

up to 6.2 MPa, with fracture strain higher than 90%. The presence of ionic DAC moieties in the

hydrogels rendered a very high swelling ratio up to 40 (g g1). These hydrogels were responsive to

temperature changes due to the presence of NIPAM units, with the transition temperature (Ttrans)

dependent on the molar ratio of NIPAM and DAC monomers. The internal electrostatic repulsion of

the NIPAM/DAC copolymer network changed upon exposure to solutions with different pH and/or

ion strength. Cyclic swelling–shrinking was demonstrated by shuttling the gels between pure water

and 0.1 mol L1 NaCl solution.