Scientists have created smart threads that can be woven into clothing and can detect gasses. Engineers created the new threads at Tufts University, and the threads can be read visually or more precisely using a smartphone camera. The threads can show color changes when exposed to gas concentrations as low as 50 parts per million.
The scientists say that when these threads are woven into clothing, they would become a reusable, washable, and affordable safety asset for use in medical, workplace, military, and rescue environments. The fabrication method used could be expanded to a wide range of dyes and detection of complex gas mixtures.
Scientists say that the threads won’t replace the precision of electronic devices commonly used for volatile gas detection, but the thread will enable detection of gases with no equipment needed. No special equipment means that no training will be required.
In the study, the team used a manganese-based dye called MnTPP, methyl red, and bromothymol blue to prove the concept works. The MnTPP and bromothymol blue detect ammonia with the methyl red detecting hydrogen chloride. All three of those gasses are commonly released from cleaning supplies and other processes.
A special three-step process traps the dye into the thread. The first step is a dip in dye and then a treatment with acetic acid. The thread is then treated with polydimethylsiloxane (PDMS) that creates a flexible seal around the thread and dye. That seal repels water and prevents the dye from fading in the wash. The PDMS material is gas permeable allowing gas to reach the thread for reaction. The research team notes that the threads also work underwater to detect dissolved ammonia.