Unsymmetrical Alveolate PMMA/MWCNT Film as a Piezoresistive E-Skin with Four-Dimensional Resolution and Application for Detecting Motion Direction and Airflow Rate

Abstract

Flexible and piezoresistive electronic skins (E-skins) with high spatial resolution are highly desired in artificial intelligence and human–machine interactions. In this study, a simple method is developed to pattern a piezoresistive layer using lithography, which can realize real-time tactile sensing and spatial resolution. The piezoresistive layer with a honeycomb hole array based on polymethyl methacrylate (PMMA)/multiwalled carbon nanotubes (MWCNTs) was fabricated using a reverse mold with a ZnO nanorod array. The device exhibits an ultrahigh sensitivity of 88 kPa–1 in the low-pressure regime (<10 kPa) and a fast response time of 110 ms owing to the conductive honeycomb structure. The E-skin-based PMMA/MWCNT honeycomb array film can be applied to monitor bending and vibration by changing the contact area of the hole walls. A 4 × 4 piezoresistive matrix was fabricated by lithography for a 16-pixel tactile-sensing E-skin, which realizes a four-dimensional resolution including the space and time resolutions of pressure points. In addition, by using the unsymmetrical structure of an alveolate PMMA/MWCNT film, the detection of direction and velocity for the movement and gas flow were realized. The obtained piezoresistive and unsymmetrical tactile sensor realized a four-dimensional resolution, including a three-dimensional space and a fourth dimension of timeline, which enables future applications of human–machine interactions.

Emerging Internet of Things driven carbon nanotubes-based devices

“…The MWCNT-gelatin hydrogel, whose deformation is correlated to the electrical resistance, has ideal electronic skin performance [256]. The strain sensors of CNTs have been incorporated into a drone system for human-machine interaction [257].…”

Applications of 2D-Layered Palladium Diselenide and Its van der Waals Heterostructures in Electronics and Optoelectronics

“…Indeed, the PdSe 2 -based electronic devices could be integrated with the piezoelectric materials, i.e., PVDF for tactile sensors [ 75 ]. For the comfort of human beings, stretchable and wearable electronics become emerging with device development such as strain sensors and electronic skin [ 76 ]. Besides, the introduction of triboelectric nanogenerators, supercapacitors [ 77 ], and batteries [ 78 ] may lead to self-powered sensors [ 79 ].…”

Tactile and Vision Perception for Intelligent Humanoids

“…Another enhancement solution is patterning microstructures at the sensing layer. [ 43–45 ] For example, Chen et al [ 45 ] patterned a piezoresistive layer with a ZnO nanorod array, and obtained high sensitivity at 88 kPa −1 in a pressure regime of <10 kPa. Similar to the capacitive‐based tactile sensors, piezoresistive architectures are also capable of detecting force in different orientations.…”