Scientists have developed a novel method of producing colored, modern threads that change color upon the detection of various gases. Woven into clothing, intelligent, gas-sensitive threads are reusable and provide an affordable safety measure in the medical, workplace, military and emergency environments.
Modern threads affect work safety
Researchers from TUFTS – an American university located in Medford, Massachusetts, have shown that visual changes in the color of woven threads can be seen with the naked eye. This seems extremely useful in places of higher risk – when working in chemical laboratories or in specialized rescue, where caution is extremely important, and the life and health of employees may be at risk. Intelligent threads are reusable, which makes them a very low-cost security measure.
The technology is to replace precision electronic devices that are commonly used to detect volatile gases. Extending the possibilities of textiles for gas detection enables reading, which does not require any additional equipment. Employees will also not need specialized training – all they need to do is notice a change in color in the strategic locations of overalls, in which modern threads will be sewn. This approach can make this technology widely available for the broadly understood workforce or poor communities that will be up to date with the information that modern textiles will give them.
How modern threads were made.
The studies used a manganese-based dye, mesotetrafenyl-morphine (MnTPP), methyl-red and bromotyl-blue dyes. The combination of MnTPP and bromotyl blue can detect ammonia, and methyl red can indicate the presence of hydrogen chloride – that is, gases commonly released from cleaning materials, plant fertilizers and chemical products. The three-stage production process stops the dye in the thread. The thread is first immersed in the dye and then treated with acetic acid, which causes the fiber to swell and the surface becomes rougher. Finally, the cord is treated with a polydimethylsiloxane (PDMS) that forms a flexible seal around the thread and dye.
– The dyes we use work in different ways, thanks to which we can detect gases with different properties – says Sameer Sonkusale, professor of electrical and computer engineering at TUFS.
Favorable research results and hope for the future.
During the tests, the dyes changed the color in a way that was dependent and proportional to the gas concentration, which was simultaneously measured by spectroscopic methods. Between the precision of the spectrometer and the human eye, it is possible to use a smartphone to read and quantify color changes or interpret color combinations using multiple threads and dyes. The threads worked even under water, detecting the presence of dissolved ammonia.
– While the PDMS sealant is hydrophobic and keeps water away from the thread itself, the dissolved gases can still reach the dye in the thread. This means that fabrics with sewn intelligent threads will be able to effectively warn against carbon dioxide when looking for oil and gas underwater – said Rachel Owyeung from the Department of Chemical and Biological Engineering of TUFTS.
Scientists say that repeatedly washing and use under water does not dilute the dyes used. This means that fabrics with modern threads will be suitable for washing, thus they will be reusable.