Cotton fabric cleans itself when exposed to ordinary sunlight

Dec 14, 2011
Cotton fabric cleans itself when exposed to ordinary sunlight

Imagine jeans, sweats or socks that clean and de-odorize themselves when hung on a clothesline in the sun or draped on a balcony railing. Scientists are reporting development of a new cotton fabric that does clean itself of stains and bacteria when exposed to ordinary sunlight. Their report appears in ACS Applied Materials & Interfaces.

Mingce Long and Deyong Wu say their fabric uses a coating made from a compound of titanium dioxide, the white material used in everything from white paint to foods to sunscreen lotions. Titanium dioxide breaks down dirt and kills microbes when exposed to some types of light. It already has found uses in self-cleaning windows, kitchen and bathroom tiles, odor-free and other products.

Self-cleaning cotton fabrics have been made in the past, the authors note, but they self-clean thoroughly only when exposed to ultraviolet rays. So they set out to develop a new cotton fabric that cleans itself when exposed to ordinary sunlight.

Their report describes coated with nanoparticles made from a compound of titanium dioxide and nitrogen. They show that fabric coated with the material removes an orange dye stain when exposed to sunlight. Further dispersing nanoparticles composed of silver and iodine accelerates the discoloration process. The coating remains intact after washing and drying.

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More information: Realizing Visible-Light-Induced Self-Cleaning Property of Cotton through Coating N-TiO2 Film and Loading AgI Particles, ACS Appl. Mater. Interfaces, Article ASAP. DOI: 10.1021/am201251d

Abstract
The visible-light-induced self-cleaning property of cotton has been realized by coating N-TiO2 film and loading AgI particles simultaneously. The physical properties were characterized by means of XRD, SEM, TEM, XPS, and DRS techniques. The visible light photocatalytic activities of the materials were evaluated using the degradation of methyl orange. In comparison with TiO2–cotton, the dramatic enhancement in the visible light photocatalytic performance of the AgI–N–TiO2–cotton could be attributed to the synergistic effect of AgI and N–TiO2, including generation of visible light photocatalytic activity and the effective electron–hole separations at the interfaces of the two semiconductors. The photocatalytic activity of the AgI–N–TiO2–cotton was fully maintained upon several numbers of photodegradation cycles. In addition, according to the XRD patterns of the AgI–N–TiO2–cotton before and after reaction, AgI was stable in the composites under visible light irradiation. Moreover, a possible mechanism for the excellent and stable photocatalytic activity of AgI–N–TiO2–cotton under visible light irradiation was also proposed.

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NotAsleep
not rated yet Dec 14, 2011
I was about to question the merit of using a fairly precious resource like Titanium to make self-cleaning clothes when I remembered the plethora of chemicals we essentially pour down the drain every time we do a load of laundry.

Maybe we should just wear titanium chain mail instead of clothes...
barakn
3.7 / 5 (3) Dec 14, 2011
Titanium metal may be precious, but only because of the effort it takes to strip oxygen from titanium dioxide, which is fairly abundant.
SemiNerd
not rated yet Dec 14, 2011
Titanium dioxide is used in vast quantities for making paint. Its cheap and abundant.

Making the metal is expensive.
eachus
not rated yet Dec 14, 2011
And note that this coating also uses AgI (silver iodide). So the cost of the treatment is probably gated by the cost of silver.
antialias_physorg
not rated yet Dec 14, 2011
So the cost of the treatment is probably gated by the cost of silver.

Silver Iodide is also not expensive. It's used in every deodorant.
Graeme
not rated yet Dec 14, 2011
@antialias_physorg : Where can you buy Silver Iodide for under $1000 a kilogram?
Guy_Underbridge
5 / 5 (2) Dec 15, 2011
yay! i can then walk around in clothes covered with inert dust and dead microbes
Isaacsname
not rated yet Dec 15, 2011
Well, I really don't need help not doing my laundry any more than I don't do it already..
antialias_physorg
not rated yet Dec 15, 2011
@antialias_physorg : Where can you buy Silver Iodide for under $1000 a kilogram?

You probably only need very little of it. Silver idodide causes pores to close (thereby exuding less sweat - thereby giving bacteria less to feed on, which in turn causes less smell).

I'm not sure whether, with thse types of clothes, a 24/7 (or rather a 12/7) exposure of silver iodide to large parts of your skin is such a great idea. Sweating does have a function. Artificially repressing it - which would be a side effect of weraing these clothes on a constant basis - can't be healthy (Not even mentioning the allergy risk of constant exposure to a chemical of this sort)
kaasinees
1 / 5 (4) Dec 15, 2011
yay! i can then walk around in clothes covered with inert dust and dead microbes

But you can rinse them off instead of using chemicals that destroy your clothes. This saves a lot of resources and energy.
rawa1
1 / 5 (6) Dec 15, 2011
I'm afraid, this coating will decrease the stability of the fabric too, not just the dirt on it.
FroguetteMiNote
1 / 5 (6) Dec 19, 2011
Too bad they used two very toxic products. Now we can be dead but with always clean clothes. (Search google scholar for "titanium dioxide toxicity", and check out Particle and Fibre Toxicology 2009, 6:35 / doi:10.1186/1743-8977-6-35)