Polymer-metal nanocomposites with 2-dimensional Au nanoparticle arrays for sensoric applications

Sensors for volatile organic compounds (VOC) are of increasing interest for various applications ever since. Here we present a novel method to achieve a fast and reversible response by employing a polymer-metal nanocomposite film with 2-dimensional Au nanoparticle arrays. Our sensors are made out of spin-coated polymer substrates on which we deposit gold clusters with a cluster density near the percolation threshold via thermal evaporation. The sensor operates on the principle of swelling of polymers in the presence of VOC. This leads to a change in the interparticle distance and therefore the conductivity of the composites. The method is fast, easy, precisely to control and the sensor fabrication process produces only a minimum amount of waste (like organic solvents). The degree of swelling primarily depends on the type of polymer and the organic solvent, i.e. solubility parameters of the polymer and the vapor. Therefore, the pattern leads to fingerprints of particular polymers towards different vapors. These fingerprints can be employed as a parameter for detecting different VOCs.