Scientists have invented an efficient way to coat cotton cloth with tiny particles of titanium dioxide. These nanoparticles are catalysts that help to break down carbon-based molecules, and require only sunlight to trigger the reaction. The inventors believe that these fabrics could be made into self-cleaning clothes that tackle dirt, environmental pollutants and harmful microorganisms.
Hong Kong Polytechnic University researchers Walid Daoud and John Xin baked 20 nanometer titanium dioxide particles into clothes for 15 minutes to create cloth that can be cleaned by standing in the sunlight. I like efforts to achieve better living through materials science. Not sure if this approach is wise though.
The first potential problem here is that when hit by photons the materials generate oxygen free radicals. Well, do you want to wear clothing that generates oxygen free radicals? It might accelerate the aging of your skin. Also, some of the oxygen radicals may react with O2 to form O3 ozone gas. It would be like walking around in a microenvironment that is like Los Angeles on a bad day (or Bakersfield or Fresno even more often). You wouldn't want to stand still too long since in order to avoid clothing pollution.
The other problem with this approach is that the oxygen radicals would probably damage the cotton fibers. Cotton is made from cellulose which is a polymer of glucose sugar. That polymer can be damaged by free radicals. So the clothing might wear out faster.
Self-cleaning clothes will be developed eventually. Though it is not clear that this approach is the one that will ultimately succeed.
|Share |||Randall Parker, 2004 June 14 12:17 PM Materials Advances|