Slashdot Mirror
Researchers Develop Self-Cleaning Clothes
Ponca City, We Love You writes "Researchers at Monash University, in Australia, have found a process to coat natural fibers such as wool, silk, and hemp that will automatically remove food, grime, and even red-wine stains by coating their fibers with titanium dioxide nanocrystals, which break down food and dirt in sunlight. Titanium dioxide is a strong photocatalyst and in the presence of ultraviolet light and water vapor, it forms hydroxyl radicals, which oxidize, or decompose, organic matter. "These nanocrystals cannot decompose wool and are harmless to skin," says organic chemist and nanomaterials researcher Walid Daoud. Titanium dioxide can also destroy pathogens such as bacteria in the presence of sunlight by breaking down the cell walls of the microorganisms making self-cleaning fabrics especially useful in hospitals and other medical settings."
Sunlight?
This is some new kind of LED, right?
"...natural fibers such as wool, silk, and hemp..." So what if I'm sitting real close to someone who is wearing spandex or nylon or some other artificial fabric? Does it eat through those?
Obviously this would be the perfect clothing for many slashbots. However its requirement of sunlight to activate the self-cleaning enzymes makes it impractical for those basement dwellers among you.
Can they modify the fabric to react to the glow of a CRT?
...man wakes up to find a pile of goo wearing his wife's very clean titanium dioxide pajamas...
I guess the old "Spill something on her dress and act concerned by patting her chest with a napkin" plan just flew out the window. Now I gotta use other plans to act innocent while copping a feel.
I guess I could try the "Make a sudden stop at a light right before it turns red and stick my arm out to make sure she doesn't fly forward" plan.
Not only that, but your skin is crawling with "good" bacteria and how does it know the difference between the "bad" bacteria to break down and the "good" bacteria on your skin?
Beer is proof that God loves us and wants us to be happy.
Any very fine mineral dust you inhale in large quantities -- and 5.0 grams per cubic meter is unbelievably dusty, like blowing a whole pack of chalk to smithereens in your office -- will cause the symptoms described in both the OSHA document and the more problematic document you cite from people who want to scare you into buying their (more expensive) "natural" products.
All particles with sharp edges, i.e. that come from minerals, irritate the delicate tissue lining your lungs if you inhale it. TiO2 is no different in this regard than, say, SiO2 -- plain old sand -- that you might inhale if you were around blasting or power sanding operations all day. (Google "silicosis.")
Furthermore, your lungs are built like lobster traps from the point of view of inhaled superfine particles: it's easy to get in, but very difficult to get out. This is why in the upper region of the respiratory tract, you have mucus that traps inhaled larger particles and cilia that beat constantly to flush them up and out, plus a cough reflex to expel the scum. But you can't have these things in the deep tissue of the lungs, because that surface area is needed for gas exchange.
So if you inhale very fine dust, it just stays in your lungs pretty much forever, jiggling around and rubbing on things, irritating them. Your body may decide to wall it off with scar tissue if it's irritating enough, which is the "fibrosis" mentioned. It's even possible if it's sufficiently irritating, like the very sharp particles of asbestos fibers, that it can stimulate lung cancer. For all we know, the only reason people get lung cancer in the large numbers they do is because, sooner or later, everyone's lungs fill up with irritating particles of all manner and description and the chronic irritation causes tumors. Unfortunately, the only way to eliminate the threat of inhaled fine dust completely is to never breathe without a heavy fine-filtering face mask.
Insofar as these clothes are concerned, the primary question would be: how is this very fine dust going to be generated? I mean, inhaling very fine silica (SiO2) dust is dangerous in exactly the same way, but you don't refuse to go to the beach or rock-climbing because you know the rock and sand has no reason to suddenly pulverize itself and become superfine dangerous dust. So how would fibers coated with TiO2 get pulverized and generate super fine dust? Don't say the motion of wearing the clothes, either, because you need much more force than this. Walking on the sand at the beach doesn't pulverize the sand particles and generated dangerous superfine silica dust, after all.