Washability of E-Textiles

Ever since e-textile technology came onto the scene, one question has lingered in the minds of the curious: Can e-textiles be washed? The short answer? Yes. However, there are some conditions that can change the answer to “sometimes.”

E-textiles vs. standard textiles

Most fabrics, such as cotton and polyester, degrade with each cycle. Elasticity changes, dye fades, and overall resilience is diminished. E-textile materials consist of electronics and conductive components in addition to fibers. So, washing an e-textile will result in some degree of degradation. There is also a different impact on e-textile functionality in wearable devices and smart garments. Conductivity and electrical resistance can both be determined with a multimeter. For many garments, we would expect them to last for anywhere from 50 to 100 washes. This standard is often too high for e-textile solutions, which can last closer to 10 to 50 wash cycles, depending on the technology.

Washability of e-textiles

Degradation is a main factor when discussing the washability of e-textiles—no matter how many washes we are talking about. However, if you are going to wash an e-textile, it is advised you do so on a delicate cycle. For reference, the LEL shows acceptable amounts of degradation with 50 cycles in cold water. However, the number of washes it takes to show degradation is highly dependent on the construction of the e-textile. To simplify this explanation, here are a few common combinations of conductive materials that can make up an e-textile material, and how they may respond to anywhere from ten to fifteen washes.

• Conductive Ink Embedded in Polyester: Conductive inks are typically made of graphite or other metal nanoparticles. When integrated directly into a textile substrate to create for example, a smart garment, conductive ink can withstand more washes with little resistance change (up to 50 washes). Greater change in resistance is seen when the ink is printed directly on to the surface of the fabric. Now, does anything change when it is placed on top of polyester fabric? If the conductive ink is waterproof, it may hold up better than if it were not. If it is integrated directly into the textile substrate, it may degrade after the ten or so washes it takes for polyester fabric to show degradation. If placed on top, it may only last for one to five washes.

• Conductive Elements Bonded to Fabric: Liquid Wire is a good example of electronics bonded to the surface of fabric. Liquid Wire produces metal gel circuitry that is bonded into plastic and textile substrates. Liquid Wire passed a wash test for performance fabrics.

Do’s and don'ts for washing e-textiles

Do:

• Use gentle detergents

• Wash on a low, delicate cycle

• Use cold water

• Wash in a garment bag

Don’t:

• Dry clean

• Use heavy bleach

• Use hot or warm water (will speed up degradation process)

• Use additional laundry products (such as fabric softeners)

• Wash loose in machine bin

For testing, make sure to follow existing standards, like those from AATCC. Or, modify a traditional standard, like AATCC 135 test to test for electrical resistance.

What the research says

In a study conducted by researchers at Georgia Institute of Technology, the washability of conductive materials was tested. A wash test was performed on samples of conductive traces to test the resistivity and resilience of the traces after being washed. The wash tests were conducted in warm water on a regular cycle, and one ounce of detergent was used. It was found that the answer may not just be in the equipment or products used to wash the conductive materials, but the conductive materials themselves and the durability of the traces. It was concluded by the researchers that the traces held up better when there was a combination of conductive thread and ink. For example, when ink was printed on top of the conductive thread and then cured. Also, the more conductive the thread, the better it survived the six washes. Another point of interest made in the study is how washability can be improved overall, and that is by encapsulating the e-textile components; which are most susceptible to water damage.

In conclusion

A very good point was made by the researchers at Georgia Institute of Technology: “If washable electronics were to make it to the consumer market, and were to be sold as garments, it is important to note that federal regulations require specific care instructions for clothes that have to be cleaned in a specific way.” This is correct. As e-textile wearables become more common, the proper way to wash them will need to be more clearly defined; what settings to use, what detergent to use, and any other laundry instructions. The everyday consumer will not have access to the kinds of machines to use in these tests, so it will be important to keep this in mind when designing and creating these products.