Hydroplastic foaming of graphene aerogels and artificially intelligent tactile sensors

Abstract

Direct foaming from solids is the most efficient method to fabricate porous materials. However, the ideal foaming fails to prepare aerogel of nanoparticles because the plasticity of their solids is denied by the overwhelming interface interactions. Here, we invent a hydroplastic foaming method to directly convert graphene oxide solids into aerogel bulks and microarrays, replacing the prevalent freezing method. The water intercalation plasticizes graphene oxide solids and enables direct foaming instead of catastrophic fragmentation. The bubble formation follows a general crystallization rule and allows nanometer-precision control of cellular wall thickness down to 8 nm. Bubble clustering generates hyperboloid structures with seamless basal connection and renders graphene aerogels with ultrarobust mechanical stability against extreme deformations. We exploit graphene aerogel to fabricate tactile microarray sensors with ultrasensitivity and ultrastability, achieving a high accuracy (80%) in artificially intelligent touch identification that outperforms human fingers (30%).

Hyperbolic graphene framework with optimum efficiency for conductive composites

“…High enhancement e ciency of PGCs Hyperbolic graphene aerogel (HGA) was prepared by our hydroplastic foaming method 30 from graphene oxide (GO) solid papers that consist of GO with average size of ~50 µm (Supplementary Fig. exceeds the e ciency ever-achieved in functional nanocomposites of diversely topologic nano llers, as shown in Fig.…”

New technologies for robotic tactile sensing and navigation

“…Being piezoresistive, they are well suited to tactile sensing. An example of the former is work at Zhejiang University which involves tactile sensors based on graphene aerogels (GAs) (Pang et al , 2020). The group has developed a hydroplastic foaming method to convert laminated graphene oxide into GAs and fabricated a microarray comprising 64 GA sensors on a 7 x 8 mm substrate.…”

Rational Design of Soft Yet Elastic Lamellar Graphene Aerogels via Bidirectional Freezing for Ultrasensitive Pressure and Bending Sensors

“…Elastic graphene aerogels can be readily fabricated by hydrothermal synthesis, [ 13 ] chemical reduction, [ 14 ] ice‐templating method, [ 15 ] liquid crystal self‐assembly, [ 16 ] emulsion‐assisted assembly [ 5a,17 ] and hydroplastic foaming [ 18 ] while their mechanical performances can be tuned by designing specific structures. Among these methods, ice‐templating method is widely used to construct both isotropic and anisotropic graphene aerogels by controlling the orientation of ice crystals during their growth process.…”