Fully organic Aerosoljet printed piezoelectric sensor

People having diabetes (according to WHO these were 9 % of the adult world population in 2014) often suffer from foot ulcers caused by reduced blood flow and nerve damage. For those people it is extremely important to wear well-fitting shoes to avoid additional stress to their feet, and successive ulcers and amputation. The piezoelectric sensor presented here could be worn constantly and help to monitor changes in the patients feet and to adapt their footwear. We have produced a flexible piezoelectric sensor, completely based on polymers. The piezoactive material is poly[(vinylidenefluoride-co-trifluoroethylene] [P(VDF-TrFE)]. The electrodes and the conductive paths are made of PEDOT:PSS with the co-solvent DMSO. The sensor has been built up by maskless aerosoljet printing on an adhesive polyester foil substrate. This process allows the printing of very fine structures in the µm-range, enabling high lateral resolution. The sensor produced for demonstration has a surface area of 0.25 mm2 and a total thickness of ~170 µm. Taking processes and materials together, we obtain a flexible and robust piezo system that can be applied on a high variety of surface materials and shapes (including arbitrarily shaped 3D surfaces and textiles). These characteristics suggest the potential use of the system in medical applications as for example in specially designed footwear for diabetes patients.