February 26 2014
Scientists Modify Cotton and Polyester to Display Repellent Properties
By modifying cotton and polyester fabrics with a coating that repels almost any type of substance, a research team from the School of Engineering and Applied Sciences and the Wyss Institute for Biologically Inspired Engineering could be close to changing the nature of several consumer and industrial products—as well as the need for laundry.
The team, headed by materials science professor Joanna Aizenberg, has exhibited various applications of the award-winning SLIPS, or Slippery Liquid-Infused Porous Surfaces, a slick coating that repels water, oil, tomato juice, eggs, wax, and blood, among other substances, since 2011.
Then, as reported in the journal Nanotechnology last month, the team displayed the same resistant SLIPS behavior in cotton and polyester materials after scientifically modifying the fabrics. Although preventing stains in everyday clothing is one of the eventual desired uses of SLIPS technology, this most recent finding has tackled the problem of providing coating to specialty textiles exposed to extreme environments. By subjecting their SLIPS-fabrics to rigorous industrial tests specified in the technical manual of the American Association of Textile Chemists and Colorists, they found that these fabrics retained exceptional protective properties even after rubbing, twisting, or washing.
“SLIPS-fabrics may provide a unique solution as a stable, anti-fouling material for specialty suits in demanding applications in extreme, contaminated environments for which no alternatives exist," Aizenberg said.
The scientists suggested a broad range of applications of this latest modification, including tactical suits for military and firefighters, medical gowns and lab coats, and specialty garments for construction and manufacturing. Furthermore, certain properties such as anti-icing would provide an advantage in large awnings, tents, and open-air buildings such as sports stadiums.
“We believe that such SLIPS-fabric is a novel material that, for the first time, confers pressure- and damage-tolerant omniphobicity on fabric-based substrates,” said Philseok Kim, a senior research scientist on the project.
When designing the super-slick coating, the scientists found inspiration in nature—in particular, from the carnivorous pitcher plant. The plant utilizes a mixture of fluids and a mechanical trap to ensnare insects. By replicating these defense mechanisms, the scientists were able to develop a porous material which could hold the water in the same way a sponge holds water.
“We do a lot of innovative science and fundamental research but at the same time we wanted to fill the gap between what you can achieve in the lab on a small scale under very controlled conditions and real world applications, “ Kim said. “Academia usually focuses on fundamental research and industry usually focuses on the practical, but we need to bridge this, to fill in this gap—this is often called translational research because you are translating core technology into real world applications.”
In keeping with the theme of translational research, scientists working with SLIPS have experimented with coating other everyday objects. They found that a coat of SLIPS improved the efficiency of various appliances, such as refrigerators, by preventing the continual defrosting in the coils, ultimately reducing costs, freezerburns, and spoiled produce. They are also studying how SLIPS acts as an anti-corrosive barrier and works against marine-fouling, which could help increase the efficiency of ships by preventing barnacles from attaching, and thus slowing down, the ship.
Beyond efficiency, the material also has the potential to change lives. The scientists said that the material could protect patients against bacterial infections, a significant problem in hospitals throughout the country.
“SLIPS can help in reducing this risk, as it prevents bacteria from colonizing and forming biofilm in the first place,” said Kim. “SLIPS basically provides a non-sticking surface that intervenes at the very first step of the colonization…. If it works in the future, it could save a lot of lives,” said Kim.
Kim said that the research team has been closely working with the CEO of the startup company and talking with several larger corporations regarding applications of SLIPS.