Abstract:

Objective As a natural material with good mechanical properties and piezoelectricity, silk is widely used in the field of intelligent textiles. However, the development of intelligent wearable textiles is limited due to its inability for normal machine washing. Therefore, it is necessary to study the washing resistance of silk-based intelligent textiles. In order to study the washing resistance and electric heating properties of silk-based wearable fabrics, this work explores the influences of screen-printing times and fabric structure on fabric conductivity, washing resistance and electric heating performance.

Method In this study, graphene oxide (GO) was repeatedly finished on the surface of silk fabrics with satin, twill and backed weaves by screen printing, and then reduced graphene oxide (RGO) modified silk fabrics were prepared by reducing agent. The apparent morphology and crystal structure of the prepared RGO modified silk fabric were analyzed by scanning electron microscope and X-ray diffractometer. The surface resistance of the sample was tested by VC890D digital multimeter, and the samples were washed according to the standard of GB/T 8629—2017. The electrical heating properties of samples were tested by infrared thermal imager.

Results The spacing between the yarns in the satin silk fabric is obvious, and the RGO sheet structure on the surface is easily interrupted. Although many RGO layers adhered on the surface of RGO modified twill silk fabric, it is prone to large voids in the warp direction. RGO modified backed weave silk fabric has a large area of RGO layer in both warp and weft directions. The untreated silk fabric and the prepared RGO modified silk fabric have basically the same characteristic peak positions in the X-ray diffraction pattern. The preparation method used in this paper has no obvious effect on the original crystal phase structure of silk. With the increase of screen-printing times, the resistance of the fabric surface gradually decreases. When the number of screen-printing times is the same, the backed weave fabric has the minimum fabric surface resistance, and which is 0.539 kΩ·cm when the fabric is screen-printed for 6 times. The minimum change in the surface resistance of the fabric after washing is achieved by screen printing for 5 times. After 9 cycles of washing, the fabric resistance of each of the three fabrics is 1.427 kΩ·cm (satin weave), 1.061 kΩ·cm (twill weave), 0.797 kΩ·cm (backed weave), respectively. Accordingly, the RGO modified satin silk fabric has good electrical heating properties, reaching a stable temperature of 96 ℃ at a current of 0.025 A, and the maximum heating rate is 10 ℃/s. When the input current value is the same, the saturation temperature of RGO modified twill silk fabric is greater than that of RGO modified backed weave silk fabric. When the input current is 0.03 A, the saturation temperatures of the RGO modified twill weave silk fabrics is 69 ℃, and RGO modified backed weave is 39.8 ℃, and the heating rates are 9.7 ℃/s (twill weave) and 4.5 ℃/s (backed weave).

Conclusion Under the same preparation conditions, the resistance of RGO modified backed weave fabric is the smallest. In addition, the resistance of RGO modified silk fabric with 6 screen-printing times is higher than that of RGO modified silk fabric with 5 screen printing times after washing. Among the RGO modified silk fabrics with three different structures, the satin weave showed better electrical heating properties. This paper shows that RGO modified silk fabric prepared by screen printing has good washing resistance and electrical heating properties, and has good application potential in the field of intelligent wearable textiles.

Key words: silk fabric, screen printing, fabric structure, reduced graphene oxide, conductivity, electrical heating property