The development of gustatory sensors is essential for the development of smart materials for use in robotics, and in the food, beverage, and pharmaceutical industries. We therefore designed a prototype of a rubber tongue embedded with a gustatory receptor mimicking a human tongue using our previously proposed hybrid fluid rubber (HF rubber) and an electrolytic polymerization technique. The fabricated gustatory receptor was composed of Pacinian corpuscles, which are well known and have already been elucidated as effective haptic and auditory receptors in previous studies. Moreover, the receptor has self-powered voltage generated as built-in electricity as a result of the ionized particles and molecules in the HF rubber. The utilization of a layered structure for the Pacinian corpuscles induced a typical response not only to normal and shear forces but to thermal variations. Typical gustatory characteristics, including the initial response voltage and the cyclic voltammogram form, were clearly varied by five tastes: saltiness, sourness, sweetness, bitterness, and umami. These results were due to ORP, pH, and conductivity.
Keywords: electrolytic polymerization; gustation; gustatory receptors; hybrid fluid (HF); mimesis; robotics; rubber; smart material; tongue.