Self-Healable and Recyclable Tactile Force Sensors with Post-Tunable Sensitivity

It is challenging to post-tune the sensitivity of a tactile force sensor. Herein, a facile method is reported to tailor the sensing properties of conductive polymer composites by utilizing the liquid-like property of dynamic polymer matrix at low strain rates. The idea is demonstrated using dynamic polymer composites (CB/dPDMS) made via evaporation-induced gelation of the suspending toluene solution of carbon black (CB) and acid-catalyzed dynamic polydimethylsiloxane (dPDMS). The dPDMS matrices allow CB to redistribute to change the sensitivity of materials at the liquid-like state, but exhibit typical solid-like behavior and thus can be used as strain sensors at normal strain rates. It is shown that the gauge factor of the polymer composites can be easily post-tuned from 1.4 to 51.5. In addition, the dynamic polymer matrices also endow the composites with interesting self-healing ability and recyclability. Therefore, it is envisioned that this method can be useful in the design of various novel tactile sensing materials for many applications.