An angle-compensating colorimetric strain sensor with wide working range and its fabrication method

Abstract

The visual response is one of the most intuitive principles of sensors. Therefore, emission and change of the colors are widely studied for development of chemical, thermal and mechanical sensors. And it is still a challenging issue to fabricate them with a simple working mechanism, high sensitivity, good reliability, and a cost-effective fabrication process. In this study, we propose a mechanical strain sensor, which has 2D photonic crystal structures in nanoscale on stretchable polydimethylsiloxane (PDMS) substrate. Due to the periodic nanostructures, the surface of the sensor produces structural colors. And when it is stretched, the periodicity of the nanostructures changes, which results in the shift of the colors. Multiple nanostructures with different periodicities are integrated on the sensor in order to extend the working range up to 150% with high sensitivity. In addition, reusable and robust molds, which are fabricated by self-assembly of nanoparticles, are used for multiple replications of sensor substrates. Thus, the fabrication process of this study is believed to be potential for possible industrial manufacturing. This study is expected to contribute to strain sensors in the future for the applications of health care, infrastructure monitoring, soft robotics, and wearable devices.

Polymer-Based Guided-Mode Resonance Sensors: From Optical Theories to Sensing Applications

“…A study by Minh et al 89 attempted to construct a colorimetric strain sensor employing PDMS film with 2D structures. They employed submicrometer polystyrene particles with diameters of 780, 510, and 536 nm and different Cr layer thicknesses to produce these structures.…”

Topologically Engineered Strain Redistribution in Elastomeric Substrates for Dually Tunable Anisotropic Plasmomechanical Responses

“…Despite being tremendously developed, these strain sensors are highly uncomfortable, as they require external power sources, excessive wiring, flexible/stretchable electrodes, and signal-processing tools for visual data monitoring. Therefore, as an alternative to these conventional electronic strain sensors, researchers have suggested optical strain sensors with visually detectable color changes triggered by external stimuli. − …”