Highly sensitive strain sensor from topological-structure modulated dielectric elastic nanocomposites

TL;DR

This paper introduces a topological-structure modulated dielectric nanocomposite for highly sensitive, flexible strain sensors with enhanced electromechanical performance, capable of real-time local strain measurement and soft actuator monitoring.

Contribution

It presents a novel design of elastic nanocomposites with topological structures that significantly improve dielectric permittivity and sensor performance over traditional materials.

Findings

Achieved ultrahigh dielectric permittivity of 113.4 at 1 kHz.

Sensor exhibits high sensitivity, wide linear range, and positive capacitance response.

Demonstrated real-time local strain measurement on complex surfaces.

Abstract

Flexible strain sensors are critical to several potential intelligent applications, such as human-machine interfaces, soft robotics, human motion detection, and safety monitoring of components. Stretchable functional materials are important components of strain sensors, and they are still major challenges for high performance strain sensors. Herein, we demonstrate a novel strategy of designing and optimizing flexible strain sensor by developing topological structure modulated high permittivity elastic nanocomposite. The topological structure with three-phase percolative nano-nanonetworks produces synergistic effects of space charge enhancement and local electric field modulation, and it gives rise to an ultrahigh dielectric permittivity (113.4, at 1 kHz, over 1500% enhancement than that of commercial elastic polyurethane matrix) and excellent comprehensive electromechanical performance, and the optimal comprehensive electromechanical performance reaches to 542.91 MPa-1, which is over 9-fold than that of commercial polyurethane elastic film. An interdigital capacitive strain sensor is designed using the topological structured elastic dielectric nanocomposite. It possesses high initial capacitance density and positive capacitance response with stain, achieving high signal-to-noise ratio, high capacitance response sensitivity, and wide linear range, and it breaks through disadvantages of negative sensitivity and narrow linear range for conventional interdigital strain sensors. The prepared integrated strain sensor arrays are able to measure local strain of convoluted surfaces and monitor the motion of soft actuators in real time, and they would make conditions for intelligent control systems and the study of morphological intelligence.