Nomex paper-based double-sided laser-induced graphene for multifunctional human-machine interfaces

Motivated by the inevitable trend of the Internet of Everything, human-machine interaction technology has gradually been permeated into people's daily life. Receptive devices that capture human behaviors and responsive devices that provide machine feedback are key components of human-machine interface. While it is a great challenge to integrate receptive and responsive devices in a well-organized way due to the limitations of material properties and device structures. In this work, we investigate the formation of laser-induced graphene on Nomex paper and propose an efficient interactive strategy based on its piezoresistive and thermoacoustic effects. Functional integration of receiving instructions (pressure-sensing capability) and providing feedback (sound-emitting capability) can be achieved by simply assembling three layers of Nomex paper that have been laser-customized on both sides. The integrated device not only has a sensitive response (∼12 relative current change and ∼50 ms response time) to the pressure similar to a gentle finger press (∼10 kPa), but also can emit a high-quality sound signal with larger sound pressure levels (∼70 dB at 1 W/cm2 power density). Furthermore, two proof-of-concept demonstrations, a press-to-audio pad and a command-responding thermo-earphone, are presented to substantiate the feasibility in information exchange activities. [Display omitted] •Laser-induced graphene layers with favorable electrical conductivity are formed on Nomex paper.•Different conductive properties between double-sided laser-induced graphene across Nomex substrate are obtained by regulating laser power.•Pressure-sensing and sound-emitting capabilities are realized taking advantage of piezoresistive and thermoacoustic effects of laser-induced graphene.•Multifunctional integration is implemented by assembling three-layer Nomex paper that feature double-sided laser-induced graphene.