Facile access to versatile N-vinylimidazole-based artificial tongue-like polymer gels

We report a facile approach to fabricate a type of N-vinylimidazole-based polymer gels which have tongue-like sensing behavior. With the use of urethane-acrylate macromonomer (UA) synthesized from a stepwise procedure as the cross-linking agent, poly(N-vinylimidazole/acrylic acid/urethane-acrylate) (G-1) polymer gels were facilely prepared via free radical polymerization. The swelling ratios, electro-sensitive behavior as well as fluorescence of the as-prepared G-1 polymer gels were systematically investigated in five aqueous solutions containing four kinds of basic tastes of sourness (citric acid and gluconic acid), sweetness (glucose), saltiness (sodium chloride) and umami (sodium glutamate), respectively. Interestingly, the G-1 polymer gels are capable of responding selectively to the aqueous solutions of different tastes, which suggests these polymer gels might be used as artificial tongue-like sensing materials.