Stretchable and Compliant Sensing of Strain, Pressure and Vibration of Soft Deformable Structures

Abstract

Soft robotic and medical devices will greatly benefit from stretchable and compliant pressure sensors that can detect deformation and contact forces for control and task safety. In addition to traditional 2D buckling via planar substrates, 3D buckling via curved substrates has emerged as an alternative approach to generate tunable and highly convoluted hierarchical wrinkle morphologies. Such wrinkles may provide advantages in pressure sensing, such as increased sensitivity, ultra-stretchability, and detecting changing curvatures. In this work, we fabricated stretchable sensors using wrinkled MXene electrodes obtained from 3D buckling. We then characterized the sensors’ performance in detecting strain, pressure, and vibrations. The fabricated wrinkled MXene electrode exhibited high stretchability of up to 250% and has a strain sensitivity of 0.1 between 0 and 80%. The fabricated bilayer MXene pressure sensor exhibited a pressure sensitivity of 0.935 kPa−1 and 0.188 kPa−1 at the lower (<0.25 kPa) and higher-pressure regimes (0.25 kPa–2.0 kPa), respectively. The recovery and response timing of the wrinkled MXene pressure sensor was found to be 250 ms and 400 ms, respectively. The sensor was also capable of detecting changing curvatures upon mounting onto an inflating balloon.

Transfer‐Free Creation of Hierarchical Wrinkle Patterns for Stretchable and Compliant Strain and Contact Sensing

“…In this work, we use a long balloon made from latex as the substrate, as we can modulate its stiffness by exploiting its thermalelastic properties. While several works in current literature have created wrinkled thin films using balloon substrates, [8,[12][13][14][15][16] none to our knowledge have exploited the thermal-elastic properties of the balloon substrate to create hierarchical wrinkle patterns. In their work, the authors demonstrated generating two wrinkle patterns (2D and 1D1D) on reduced graphene oxide thin films using balloons.…”