Authors: E. Laukhina, R. Pfattner, L.R. Ferreras, M. Mas-Torrent, V. Laukhin, C. Rovira, J. Veciana
Affilation: Institut Ciencia de Materials de Barcelona (CSIC)/CIBER-BBN, Spain
Pages: 80 - 83
Keywords: thin films, strain sensors
The development of intelligent materials that respond to the application of external stimuli is of major interest for the fabrication of artificial sensing devices able to sense and transmit information about the external changes produced in our environment. If these materials can be integrated on flexible and transparent substrates and processed employing low-cost techniques their appeal is greatly increased. Here, we show that by using soft organic bi-layered thin films, composed of a polymeric matrix with a top-layer formed by a nanocrystalline network of a conducting molecular charge-transfer salt, it is possible to translate micron-scale elastic elongations of the film into reversible deformations of the soft organic charge-transfer salt crystals at the nanoscale. These multiple length scale movements are responsible of the ultra sensitive piezoresistive properties of the thin films that are extremely sensitive to strain changes with durable, fast and completely reversible responses. Advantageously some of such thin films show a sensitivity one order of magnitude larger than commercial electromechanical sensors and can be incorporated on many materials, like fabrics, showing any temperature dependence that simplify their incorporation on devices. A few proof-of-concept experiments with simple prototypes based on such soft nanocomposite polymeric materials will be also presented.