Effect of natural dyes on the sensitivity of knitted strain sensors

Abstract

Soft gloves with incorporated strain sensors for wrist flexion monitoring have been proposed as an aid to the physiotherapists assisting stroke patients with their hand rehabilitation exercises. Most of the reported strain sensor testing methods only involve unidirectional fabric tensile tests, but in actual applications, when sensors are on a knitted glove, the fabric is subject to complex multidirectional stretching. The purpose of this study was to investigate how natural dyes affect the sensing performance of a knitted strain sensor seamlessly integrated into a fingerless glove, aimed at detecting wrist flexing motions.The results show that natural dyes improve the knit sensor performance by affecting its strain, except for the sensors made using 100% baby alpaca fibers. The fiber composition clearly influences the sensitivity after dyeing, and osage dye is less effective than the logwood dye, except for the sensors made with 100% bamboo yarn.