Highly reproducible printable graphite strain gauges for flexible devices

• Graphite strain gauge is printed on flexible plastic foil.
• Xenon flash lamp appears to be efficient for curing the graphite ink.
• Printed strain sensor shows a large gauge factor and fast response.
• We report a highly reproducible sensor response under cyclic mechanical deformation.
• Temperature compensation for strain gauge is proposed.

A growing area for the electronics industry is the development of flexible components for novel devices. Controlling the flexibility of such devices requires the precise and reliable measurement of strains in a manner compatible with the form and function of the device. In this article, we demonstrate the fabrication and characterization of printed strain gauges with a gauge factor as high as 19.3 ± 1.4, fast signal response and high reproducibility. The device is made of graphite ink deposited by screen printing on a plastic substrate. The flexible printed sensor is capable of precisely measuring repetitive tensile and compressive bending strain changes. An approach for eliminating the temperature-induced errors of strain gauges based on neutral axis engineering is also described.