Stretchable and Skin-Mountable Temperature Sensor Array Using Reduction-Controlled Graphene Oxide for Dermatological Thermography

Abstract

Since thermometry of human skin is critical information that provides important aspects of human health and physiology, accurate and continuous temperature measurement is required for the observation of physical abnormalities. However, conventional thermometers are uncomfortable because of their bulky and heavy features. In this work, we fabricated a thin, stretchable array-type temperature sensor using graphene-based materials. Furthermore, we controlled the degree of graphene oxide reduction and enhanced the temperature sensitivity. The sensor exhibited an excellent sensitivity of 2.085% °C–1. The overall device was designed in a wavy meander shape to provide stretchability for the device so that precise detection of skin temperature could be performed. Furthermore, polyimide film was coated to secure the chemical and mechanical stabilities of the device. The array-type sensor enabled spatial heat mapping with high resolution. Finally, we introduced some practical applications of skin temperature sensing, suggesting the possibility of skin thermography and healthcare monitoring.

Recent advances in multimodal sensing integration and decoupling strategies for tactile perception

“…In addition, conductive nanoparticles [69] (Pt, Ni, Al), graphene [70], hydrogels [71], and ion liquid are commonly employed as resistive thermo-sensitive materials. The band gap structure and oxygen functional groups of reduced graphene oxide can be regulated by adjusting the degree of reduction, resulting in different temperature coefficients [72]. Jia et al have reported a serious of thermal sensors based on ion liquids, including 1-ethyl-3-methylimidazolium acetate ([EMIm][Ac]) [73], green electrolytes [28] and 1-Ethyl-3-methylimidazolium bis(trifluoromethyl sulfonyl)imide ([EMIm][Tf 2 N]) [74], which exhibit electrical conductivity increasement with temperature increasing.…”

Breathable and Durable Tactile e-Skin Based on S-Shaped Nanofiber Networks by Patterned Additive Manufacturing

“…The first is the field where the tactile e-skin is attached to the real human skin, − and the second is the field where the tactile e-skin is attached to the surface of bionic human skin. − In fact, the tactile e-skin used in both fields has a high demand for breathability. Currently, there are remarkable application cases of tactile e-skin attached to real skin, − which have different sensing principles, have flexible structures, and are made of functional materials. Moreover, tactile e-skin has broad application prospects in medical treatment, sports monitoring, and quantitative perception of tactile pressure on the body surface.…”

Solution-Processed Flexible Temperature Sensor Array for Highly Resolved Spatial Temperature and Tactile Mapping Using ESN-Based Data Interpolation

“…Flexible sensors present substantial technological opportunities, such as monitoring temperature distribution over a large surface area through tape-like attachment of sensors to target objects. , However, covering extended areas implies the requirement for numerous sensors, fueling the need for low-cost fabrication approaches such as printing or transfer methods. To date, various cost-effective flexible temperature sensors have been reported in the literature that use metal-, semiconductor-, and composite-based material systems, − each with distinct characteristics in terms of long-term stability and high sensitivity. ,, Graphene oxide mixed with poly­(ethylene oxide) and poly­(vinylidene fluoride) has been employed in sensing devices, exhibiting a high sensitivity of ∼11.2%/°C . Long-term stability was achieved by employing carbon nanotube and SnO 2 nanoparticles; however, the sensitivity (∼0.23%/°C) is sacrificed to realize high stability.…”