Micro-grooved anisotropic hydrophobic flexible and stretchable strain sensors

Abstract

Flexible and stretchable strain sensors are beneficial in health monitoring, human-robot interactions, soft robotics, etc. In this study, fabrication of anisotropic and hydrophobic flexible strain sensors is reported. The sensors were prepared by a replica molding process using polydimethylsiloxane+carbon nanotubes composite. Four micro-grooved textures were replicated with varying dimensions. They showed anisotropic wettability, Young’s modulus, and electrical conductivity, when measured parallel (∥), perpendicular (⊥) to grooves. Water contact angle increased from 104 ± 1° (untextured) to 118 ± 9° and to 110 ± 3° when measured parallel (∥), perpendicular (⊥) to grooves, respectively. Similarly, Young’s moduli are 2.16 MPa (∥), 1.69 MPa (⊥) to grooves and 1.39 MPa (untextured), while electrical conductivity are 7.61 ± 1.33 S/m (∥) and 4.88 ± 0.82 S/m (⊥) to grooves. Thus, the prepared sensors could be useful in multidimensional strain sensing.