Smart Skins Based on Assembled Piezoresistive Networks of Sustainable Graphene Microcapsules for High Precision Health Diagnostics

Abstract

The environmental impact of plastic waste has had a profound effect on our livelihoods and there is a need for future plastic‐based epidermal electronics to trend toward more sustainable approaches. Infusing graphene into the culinary process of seaweed spherification produces core‐shell, food‐based nanocomposites with properties exhibiting a remarkably high degree of tunability. Unusually, mechanical, electrical, and electromechanical metrics all became decoupled from one another, allowing for each to be individually tuned. This leads to the formation of a general electromechanical model which presents a universal electronic blueprint for enhanced performances. Through this model, performance optimization and system miniaturization are enabled, with gauge factors (G) >108 for capsule diameters (D) ≈290 µm and produced at a record rate of >100 samples per second. When coalesced into quasi‐2D planar networks, microcapsules form the basis of discrete, recyclable electronic smart skins with areal independent sensitives for muscular, breathing, pulse, and blood pressure measurements in real‐time.

High‐Resolution Printed Ethylene Vinyl Acetate Based Strain Sensor for Impact Sensing

“…[32] However, over the whole strain range the response of a stretchable sensor based on an elastomer-filler composite to applied strain is exponential (Equation 1), and a simplified equation to describe the strain sensitivity (G) can be defined as Equation (2). [33,34]…”

“…As shown in Figure 5d, based on fitting Equation ( 2) to the linear range of R/R 0 in a semilogarithmic plot, the estimated strain sensitivity of our sensor is 7. The threshold after which the resistance change becomes nonlinear (in the semilogarithmic plot), i.e., the working factor, [32,33] is estimated to be 0.067. We examine the durability of the strain sensor response by applying 1000 cycles of 1% strain.…”