Direct printing of surface-embedded stretchable graphene patterns with strong adhesion on viscous substrates

The graphene patterns with piezoresistance behaviors, originating from the structural deformation and band-structure shift under strain, represent an attractive characteristic for developing the small strain (< 10%) sensors for wearable devices. However, the insufficient adhesion between the patterns and sub-strates has significantly limited their utility and reliability. Here, the surface-embedded graphene pat-terns were directly deposited on polydimethylsiloxane (PDMS) surfaces without hydrophilic treatment via the embedded droplet printing (EDP). The viscous PDMS films instead of the solid ones were used as substrates, and the graphene patterns were partly embedded onto the viscous PDMS surfaces. To assess the adhesion performance, a series of tests were performed. In the bending and tensile tests, the patterns strongly adhered to the PDMS films. Further, the patterns had a favorable increase in resistance in the tensile strain range of 0-3.5%. The resistance of the surface-embedded graphene patterns exhibited a negligible change for over 3 min in the ultrasonic bath. Finally, the relative resistance R/R0 remained constant after the first two adhesion tests using a 3M tape. The surface-embedded graphene patterns exhibited a strong adhesion to the flexible/stretchable substrates, indicating the application pro-spect in the field of flexible devices. (C)& nbsp;2022 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.

Automated summary

Surface-embedded graphene patterns with piezoresistance behaviors are promising for developing small-strain sensors for wearable devices. However, the insufficient adhesion between the patterns and substrates has limited their utility. In this study, graphene patterns were directly deposited on PDMS surfaces using embedded droplet printing. The adhesion performance was evaluated through various tests, and the results demonstrate strong adhesion between the patterns and PDMS surfaces, indicating potential applications in flexible devices.