Ultrasensitive flexible strain sensors based on graphene nanoplatelets doped poly(ethylene glycol) diglycidyl ether: Mask breathing monitoring for the Internet of Things

Ultrasensitive and stretchable strain sensors based on graphene nanoplatelet (GNP) doped poly(ethylene glycol) diglycidyl ether (PEGDGE) for human motion monitoring purposes with remote tracking by using Internet of Things (IoT) technologies are synthesized. The quasi-static and cycling responses under both tensile and compression conditions of nanocomposites are studied in detail. On one hand, quasi-static analysis shows very high values of the gauge factor, reaching values around 50-100 at low strain levels (1-2%) and 1000-2500 at high strain levels (10%) in tensile mode, with increasing sensitivity with decreasing GNP content. In addition, electromechanical response under 500 tensile and compression load cycles up to 1%, 2.5%, and 5% strain levels proves their high stability and as a result, their high sensitivity to detect a low degree of strain levels. Three general proofs-of-concept demonstrate that these sensors can detect several types of deformations such as pressure, bending, and twisting. Finally, human breathing is monitored with the sensor attached to a conven-tional mask. Different breath rhythms combining the calm and excited states of a person walking are remotely sent and monitored on the internet by using different IoT platforms.