Wash Testing of Electronic Yarn

Abstract

Electronically active yarn (E-yarn) pioneered by the Advanced Textiles Research Group of Nottingham Trent University contains a fine conductive copper wire soldered onto a package die, micro-electro-mechanical systems device or flexible circuit. The die or circuit is then held within a protective polymer packaging (micro-pod) and the ensemble is inserted into a textile sheath, forming a flexible yarn with electronic functionality such as sensing or illumination. It is vital to be able to wash E-yarns, so that the textiles into which they are incorporated can be treated as normal consumer products. The wash durability of E-yarns is summarized in this publication. Wash tests followed a modified version of BS EN ISO 6330:2012 procedure 4N. It was observed that E-yarns containing only a fine multi-strand copper wire survived 25 cycles of machine washing and line drying; and between 5 and 15 cycles of machine washing followed by tumble-drying. Four out of five temperature sensing E-yarns (crafted with thermistors) and single pairs of LEDs within E-yarns functioned correctly after 25 cycles of machine washing and line drying. E-yarns that required larger micro-pods (i.e., 4 mm diameter or 9 mm length) were less resilient to washing. Only one out of five acoustic sensing E-yarns (4 mm diameter micro-pod) operated correctly after 20 cycles of washing with either line drying or tumble-drying. Creating an E-yarn with an embedded flexible circuit populated with components also required a relatively large micro-pod (diameter 0.93 mm, length 9.23 mm). Only one embedded circuit functioned after 25 cycles of washing and line drying. The tests showed that E-yarns are suitable for inclusion in textiles that require washing, with some limitations when larger micro-pods were used. Reduction in the circuit’s size and therefore the size of the micro-pod, may increase wash resilience.

An investigation of temperature-sensing textiles for temperature monitoring during sub-maximal cycling trials

“…The hardware module was removed before washing, however the Eyarns, which were incorporated onto the cycling suit's inner surface, were not. It has been shown in the literature that after 25 cycles of machine washing and line drying that 80 % of temperature sensing E-yarns continue to function correctly [24]; for the temperature sensing E-yarn that broke during this study a partial failure occurred, where readings at room temperature could be taken but not at 37 °C, which implied a partial breakage in the wire interconnections. When subjected to machine-washing and machine drying trials the only observed failure mechanism for the temperature sensing E-yarns was the physical breakage of the copper wire at the wire-micro-pod interface [24], this type of breakage should not result in erroneous temperature readings.…”

“…The temperature sensing E-yarns utilized in this work were similar to those previously described in the literature [20,22,23] and identical to the design described here [24]. Unless otherwise stated the E-yarns were produced using a four-stage, semi-automated production process [25,26].…”

Design of Electro-Thermal Glove with Sensor Function for Raynaud’s Phenomenon Patients

“…In the meantime, it is important to study the washability and the effect of water on the electro-thermal behaviors of the fabric, since this material is used mostly in a moist and watery environment. The water or detergents used to wash, and the washing cycle can affect the performance of a conductive fabric [ 40 ]. Yet, the purl fabric was able to maintain an even temperature distribution after several washing cycles.…”

Wearable Textile UHF-RFID Sensors: A Systematic Review

“…Currently, for textile UHF-RFID sensors, related reliability researches are constantly advancing with the development of textile UHF-RFID sensors. The reliability researches mainly focus on the impacts from sensitive features of textile UHF-RFID sensors, such as the washing reliability [71][72][73], corrosion-resisting reliability, strain and bending reliability.…”