Photo catalytic degradation of odorous component

AREAS OF APPLICATION:

• Hospital garments
• Sports wears
• Military uniform

• Upholstery

LIMITATIONS OF SELF CLEANING FABRIC:

 

Breakthroughs in nanotechnology have made self-cleaning fabrics both practical and economical. With commercial production making the technology readily available to the masses, will washing machines and laundry detergent become obsolete?

There are several factors limiting how quickly current self cleaning fabric would be able to break down organic compounds. Sunlight is the best source of light for activating the self-cleaning process. A ketchup-stained shirt would have to be left outside in the sun for at least a day in order to remove the stain. However, for military persons or hikers, who are outside in the sun for long periods of time without the time or means to clean their clothes, self-cleaning fabric would be ideal. It's also important to note that the newly developed method for producing self-cleaning fabric has only been developed for cotton.

Further research would be required to test ways of applying titanium dioxide nanofilms to other textiles.

PROBLEMS WITH SELF-CLEANING FABRIC:

The main reasons that self-cleaning fabrics require a lot of time to break down stains is because titanium dioxide is very inefficient at using energy from sunlight. The titanium dioxide serves as a catalyst for the break down of dirt molecules by providing electrons that oxidize oxygen molecules in the surrounding air. The electrons are freed from the titanium dioxide via the photoelectric effect. But because of titanium dioxide's high band gap energy, only high energy blue and UV light photons have enough energy to excite electrons to the conduction band. High energy blue and UV light only make up 3% of the solar spectrum, so titanium dioxide can only use a very small portion of the sun's energy to break down stains.

Excitation of electrons to the conduction band is only the beginning of the cleaning process. These electrons must then react with oxygen atoms, which then react with the dirt particles. All of these reactions are limited by access to and the amount of freed electrons in the titanium dioxide. So for a large stain, a lot of light energy is needed before the fabric can fully break it down.