Zhao, Qian, et al. Journal of Applied Polymer Science 115.5 (2010): 2940-2945.
This study examined the synthesis and properties of a poly(acrylamide-co-diallyl dimethyl ammonium chloride) [poly(AM-co-DADMAC)] hydrogel prepared in a water-ionic liquid (IL) binary mixture.
Synthesis Process:
The hydrogel was synthesized through free-radical copolymerization of acrylamide (AM) and diallyl dimethyl ammonium chloride (DADMAC) in the presence of the crosslinker N,N'-methylenebisacrylamide (BIS). The reaction was conducted in a binary solvent system consisting of the ionic liquid [emim]BF4 and deionized water. After adding initiators (APS and TEMED), polymerization proceeded at room temperature for 8 hours. The resulting hydrogel was purified by immersion in deionized water for one week, with water changes every 12 hours. Finally, the gel was cut into standardized pieces and dried at 40°C until a constant weight was achieved. Samples synthesized with varying IL contents were labelled IG0 to IG4.
Key Results:
Hydrogels synthesized in the IL-water system exhibited significantly higher equilibrium swelling ratios compared to those prepared in pure water, with swelling increasing proportionally with IL content. DSC revealed that dry hydrogels formed in the IL-water mixture had notably lower glass-transition temperatures. Mechanical testing demonstrated improved fracture toughness in gels synthesized with IL. Furthermore, the hydrogels showed electro-responsive behavior, shrinking under a direct-current electric field. Samples prepared in the IL-water system responded more rapidly to electric stimulation than their water-synthesized counterparts.
Liu, Fu, et al. Reactive and Functional Polymers 86 (2015): 191-198.