Many used materials are recycled and made intofabrics. It would be surprising to know that fabrics, even those that are old,lying in the back of our wardrobes can be transformed into batteries!

We might hear energetic people saying, "I am fully charged".How about if our costume is also charged? This is one more wonder resultingfrom the advancements in technical textiles. Researchers from the University ofStanford have used the carbon nanotube ink which turns ordinary fabrics intowearable batteries. Innovations of wearable electronics have made fabrics thatcan act as batteries.

A successful method has come up wherein a special ink madeof carbon nanotubes are used to change ordinary cotton or polyester fabric intobatteries. These start functioning when they are folded and twisted. The ink ismade from single walled carbon nanotubes. When the fabric is dipped in the ink,carbon nanotubes get aligned on the existing fibres in the fabric. When thefabric dries, it still retains its flexibility and stretchability while becomesconductive. Researches also proved that loading the fabric with psuedocapacitormaterials increased the areal capacitance of the fabric 24 times more.

The special ink used in this process is made of carbonnanotubes, cylinders of carbon just billionths of a metre across. It can serveas a dye and just turn a simple' t-shirt' into an 'e-shirt'. The fabric issimply dipped into a batch of nanotube dye, pressed to thin and even out thecoating. This treatment given a conductivity of 5 S/cm to the fabrics. A simplemechanical pressing gives the fabric a conductivity of 125 S/cm creating ahighly conductive material. The conductivity can be further increased byincreasing the number of dipping and drying cycles. Stretching also increasesthe conductance which is believed to be, due to the mechanical contacts betweenthe fabric fibres.

The process is very simple and scalable as dyeing fibres andfabrics. The interwoven fibres of fabrics are similar to those of paper and aresuited to absorb the nanotube ink thereby maintaining an electrical connectionacross the whole area of the apparel. The fabric does not lose their conductiveproperties even after washing and wringing. Water does not affect the carbonnanotubes residing in the fibres. It maintains its properties even whenstretched or folded. This gives a positive implication that this technology canbe applicable for everyday use.

Applications that were previously considered as 'impossible'with conservative electronics technologies are made possible through theprocess of wearable electronics. But the field of wearable electronics wheredevices are integrated into clothing is still at the nascent field and needs tobe developed further.

References:

1. "Stretchable, Porous, and Conductive Energy Textiles", American Chemical Society Publications, Jan 5, 2010, http://pubs.acs.org
2. http://www.digitaltrends.com
3. &sec=article&uinfo=<%=server.URLEncode(2346)%>" target="_blank">http://news.bbc.co.uk