Scientists invent smart, color-changing threads capable of detecting toxic gases

Using devices to detect toxic gases present around us could be expensive and require training to use. Scientists have found a cheap alternative to it by creating smart threads woven into clothing and change color when such gases are present.

A team from Tufts University recently created new color-changing smart threads able to detect hazardous gases present. The team infused regular pieces of thread with three types of dye: MnTPP, bromothymol blue, and methyl red. The first two change color when exposed to ammonia gas, whereas the third reacts to hydrogen chloride.

New Atlas reported, each thread was first dipped in one of the dyes after which it was treated with acetic acid, which caused the fiber to swell and made its surface coarser, which may have allowed for better binding of the dye to the thread. Finally, an organic polymer called polydimethylsiloxane (PDMS) was applied to the thread, which created a flexible and water-repellent yet as-permeable seal around the dyed fiber.

Upon testing, the treated threads responded to gas concentration as low as 50 parts per million, by reliably and consistently changing color. Even the threads were reactive underwater where the fibers detected the dissolved ammonia. Even after repeated washing, the PDMS coating kept the dye from wearing out of the gas-sensing thread.

Though the thread can be detected easily by naked eye, experts suggested to use a smartphone for more precise reading which would allow the detection of multiple gases as once, as per Science Daily. These threads are reusable, washable, and affordable safety asset in medical, workplace, military and rescue environments.

Moreover, this ‘smart thread’, as per researchers, won’t be a replacement for electronic detectors, but would help cut down the barrier of training and expertise. Researchers hope to develop the technology more by utilizing more dyes, and enabling it to detect a wider range of gases.