Scientists from Massachusetts Institute of Technology (MIT) have developed a new coating that can make natural fabrics such as cotton and silk water repellant. Water-resistant fabrics are effectively used for many things including rainwear to military tents, but the traditional water-repellent coatings are found to persist in the environment that accumulates in our body as well. And for safety, the conventional-repellent coating is on a verge to phase out.
The phasing out of the conventional coating results in a big gap that needs to be filled by some safe substitute. The research team from MIT shows up trying to fill the gap with its potential solution; an invention that not only affixes water-repellency to natural fabrics such as cotton and silk but rather more effectively than the existing coating.
The challenge has been driven by the environmental regulators because of the phase-out of the existing waterproofing chemicals – Kripa Varanasi, MIT professors
According to him most fabrics that say water-repellent are actually water resistant which means standing out in the rain will eventually let water in. The ultimate goal according to Varanasi is to find a repellent material that will make the water droplets bounce back.
Materials used to make the repellent fabrics, consist of long polymers with perfluorinated side- chain. The researchers combined the shorter-chain polymer that, by itself, confers some hydrophobic properties and has been enhanced with some extra chemical processing named as the initiated Chemical Vapor Depositor (iCVD).
The existing coatings are liquid-based, so the fabric has to be immersed in the liquid and then dried out. This might clog the pores of the fabric that leads to a second manufacturing step in which air is blown through the fabric to reopen those pores, adding to the manufacturing cost.
The iCVD coating method is used to fabricate a very thin, uniform coating that follows the outline of the fibers and does not lead to any clogging of the pores further thus, not requiring the second process to reopen the pores.
The coated fabrics have been subjected to a bombardment of tests in the lab, not only with water but with various other liquids including coffee, ketchup, sodium hydroxide, various other acids, etc. finally proving itself as a well waterproof natural fabric or water-repellent fabric coating to all of them.
Via: MIT News