3D Printing of Soft Strain Sensors
Increasing interest in wearable electronics, human/machine interaction, and soft robotics, among other areas, has motivated the development of electronic devices with conformal and extensible form factors – stretchable electronics. Due to the disparate mechanical properties of soft objects and conventional rigid electronics, combining electronic capability with high degrees of conformality and extensibility has proven to be a difficult problem from both a device fabrication and materials viewpoint. To mitigate many manufacturing problems associated with current stretchable electronics, we present a novel manufacturing technique – embedded three dimensional printing (e-3DP). e-3DP involves the deposition of a viscoelastic ink into a supporting liquid reservoir that is cured post printing to produce a monolithic structure. In this work, we employ e-3DP in conjunction with a conductive ink and an elastomeric reservoir to produce highly stretchable soft strain sensors. First, we produce 2D strain sensors with gauge factors similar to conventional metallic strain gauges for strains up to 100%. We then demonstrate e-3DP as a facile mechanism to produce sensors with complex form factors in a highly scalable manner. Finally, we use e-3DP to fabricate soft sensors within functional devices that exhibit the possible employment of similar sensors in devices for biomechanical sensing and/or human-machine interfaces.
Embedded 3D Printing of Strain Sensors with Highly Stretchable Elastomers, J.T. Muth, D.M. Vogt, R.L. Truby, Y. Menguc, D.B. Kolesky, R.J. Wood, and J.A. Lewis, Advanced Materials, vol. 26, no. 36, 2014.