Smart Clothes

Miniaturised biosensors in a textile patch that can analyse body fluids, and fabrics that create energy while you are jogging. Scientists develop even more and exiting uses of nanofibres and nanosensors in fabrics.

It is 7 o’clock in the morning. You check yourself in the mirror, adjust your collar, and consider the hectic day ahead. But at least you know that the stress won't damage your health, for this is no ordinary set of clothes you are wearing. Embedded within the fabric are numerous sensors, constantly monitoring your vital signs. If danger signs are detected, the garment is programmed to contact your doctor – and send a text message telling you to take it easy.
A cluster of EU research projects (SFIT Group) is supporting this burgeoning field of smart fabrics, interactive textiles and flexible wearable systems. Jean Luprano, a researcher at the Swiss Centre for Electronics and Microtechnology (CSEM), coordinates the BIOTEX project.
“One of the most obvious applications for smart fabrics is in the medical field,” he says. “There has been a good deal of progress with physiological measurements, body temperature or electro-cardiograms. But no-one has yet developed biochemical sensing techniques that can take measurements from fluids like sweat and blood.”

One of the main achievements of the project has been the development of a suite of prototype ionic biosensors, capable of measuring sodium, potassium and chloride in sweat samples. Another probe measures the conductivity of sweat and a miniaturised pH sensor uses colour changes to indicate the pH of sweat. read more

Piezoelectric nanofibres
Another smart application of fabrics is the use of piezoelectric nanofibres.Scientists in the US have developed novel brush-like fibres with a piezoelectric effect, that generate electrical energy from movemen

Weaving them into a material could allow designers to create smart clothes which harness body movement to power portable electronic gadgets. Writing in the journal Nature, the team say that the materials could also be used in tents or other structures to harness wind energy. Dr Dianne Jones, technical director of textile electronics firm Fibretronic, said that as the market for wearable electronics expands, technologies such as the nanofibres would become increasingly attractive. "Any new power source which could provide a more integrated and soft solution in place of conventional hard battery technology would be very attractive for clothing or other electronic textile-based applications," she said.

The nano-generators, as the technology is known, consist of pairs of fibres that look similar to tiny, bendable bottle-brushes. At the core of each fibre is a Kevlar stalk. "On the surface we grow crystals called nanowires," said Professor Wang of the Georgia Institute of Technolog

Each tiny wire is 30-50 nanometres (billionths of a metre) in length and is made of zinc oxide.One of the bristled fibres is also dipped in gold to act as an electrode. When the pair is scrubbed together they create a small amount of electrical energy. "The fibre has a piezoelectric effect," said Professor Wang. "This is an important effect that converts mechanical energy to electricity." Experiments with the prototypes showed that two 1cm-long fibres could generate a current of four nanoamperes and an output voltage of about four millivolts. "If we can optimise the design we can get up to 80 milliwatts per square metre of fabric - that could potentially power an iPod." read more