Sensor properties of filled polymer composites

Abstract

Polymer composite films are proposed as potential materials for use in sensing the gases and vapours of organic liquids. The basic principle of the operation of the sensor relies on a marked change in the electroconductivity of the polymer composite system when the filler concentration is near the percolation threshold. We propose a simple model that agrees with the experimental findings. The model assumes the formation of a hopping conductivity infinite cluster before the true percolation threshold of the system is reached. The conductivity response is determined by the dependence of the hopping probability on the relative permittivity of the polymer matrix. Humidity sensors, based on the proposed principles, are described.

Polyvinyl alcohol–In2O3 nanocomposite films: synthesis, characterization and gas sensing properties

“…44a Based on the investigations by various groups, it is generally accepted that the properties of the fillers, such as size, aspect ratio, and surface groups on the filler particles, the aggregate/agglomerate structure of the filler particles in the matrix before/during final processing, the properties of the matrix including viscosity and crystallinity, and the interfacial energy between matrix and filler determine the percolation threshold of a polymer conducting composite. 46 Godovsky and coworkers 47 have studied the sensor behavior of PVA-CuS (particle size 12 nm) nanocomposites towards water vapor. They stated that the dependence of resistivity of CuS-poly-vinylacetates (12 nm size of filler particles) on water pressure could be due to the variation in dielectric constant of the polymer upon adsorption of polar molecules, resulting in the formation of a chain-like conducting cluster.…”

Nanocomposites based on polyolefins and functional thermoplastic materials

“…An even more expanding area of nanoscience is devoted to the study and preparation of innovative nanocomposite structures in order to create optically functional materials 261, 262. Noble metal nanoparticles or semiconducting nanocrystals efficiently incorporated into several polymeric matrices enhance their optical properties (absorption, luminescence and nonlinearity) thanks to the size and growth stabilization provided by the macromolecular support 261, 263–272…”

Preliminary Study of the Interaction of Metal Nanoparticle-containing Poly-p-xylylene films With Ammonia

“…Another reason for the observed sharp change in resistivity was mentioned by Godovskii et al 8,9 They stated that the dependence of resistivity of CuS-poly-vinylacetates (12 nm size of filler particles) on water pressure could be due to the variation in dielectric constant of the polymer upon adsorption of polar molecules, resulting in the formation of a chain-like conducting cluster.…”