A no-crosstalk multi-functional tactile sensor for precise physiological monitoring

Tactile sensors with multifunctional sensing characteristics enhance people’s perception of external stimuli and have become an indispensable part of human–computer interaction. However, constructing a multi-functional tactile sensor that is able to respond to multiple stimuli without signal crosstalk still remains challenging. Here, we proposed a temperature–pressure integrated multi-functional tactile sensor (TP-MTS) by coupling thermoresistive and contact-electrification effects, which can simultaneously detect human body temperature and physiological motion. A sensing electrode model was validated by using a PVDF/PEG/Gr (polyvinylidene difluoride/Polyethylene terephthalate/graphene) composite thermoresistive film instead of the traditional metal as the electrode of the pressure sensing unit. The multi-functional tactile sensor converts temperature and pressure stimuli into two independent output signals from different paths, realizing simultaneous detection of temperature and pressure without signal crosstalk. The TP-MTS can achieve real-time temperature monitoring with a minimum resolution of 0.1℃ and a sensitivity of 1.51 % ℃^-1 and it could also detect pressure in a wide pressure range (0.25 kPa ∼ 253.87 kPa) with the sensitivity of 3.73 kPa⁻¹. Through the structure design and the huge impedance difference between the thermosensitive film and the triboelectric unit, the real-time monitoring of temperature and pulse is realized simultaneously in a single device without crosstalk.