Printed strain and stress sensors could be used in sports medicine

US - Smart textiles are expected to become an important family of products predicts researchers at the US National Textile Centre, University of Massachusetts Dartmouth.

 

The properties of conducting polymers deposited onto textiles were studied over 10 years ago by workers at Los Alamos and Milliken who also tested these materials as gas sensors. More recently, workers at Wollongong have demonstrated that elastic textiles impregnated with conducting polymers, by in situ chemical polymerization, can act as strain sensors that can be used to track the motion of human joints. A similar approach can be used to make pressure-sensing foams. Others have studied the strain sensing mechanism in more detail and have shown that two effects are important.

 

The researchers at NTC aimed to print stress and strain sensors on textiles to provide information about the actions of the body for the purposes of controlling and monitoring muscle action. They envisaged printing arrays of conductive piezoresistive sensors onto fabrics and using these to provide semi-quantitative information about the motion of a piece of clothing or other textile. The conducting polymer ink is a nanoparticulate suspension which dries to a conducting film. The conductivity is thought to involve quantum tunneling between particles.

 

The following findings were reported by Prabir K.Patra, leader; Paul D. Calvert, Chi Hau Chen, Qinguo Fan (UMass Dartmouth):

(1) inkjet print seed layers on fabric and

(2) convert these seed layers into metallic lines by electroless plating.

We printed a suspension of 1.3 % by weight poly- (3,4- ethylenedioxythiophene)-poly-(4-styrenesulfonate) {PEDOT