Preparation of gold–poly(vinyl pyrrolidone) core–shell nanocomposites and their humidity‐sensing properties

Abstract The humidity‐sensing properties of gold (Au)–poly(vinyl pyrrolidone) (PVP) core–shell nanocomposites were investigated. Au–PVP nanocomposites were synthesized and then incorporated into a capacitive‐type humidity sensor as a dielectric. Because of the adsorption/desorption of water molecules, the variation of capacitance under different humidity levels was examined by the capacitance–frequency conversion circuit and recorded by a LabVIEW system in terms of the frequency shift. As the relative humidity (RH) increased from 11.3 to 93%, the output frequency decreased monotonically, with a sen sitivity of about −136 Hz/% RH. Also, the good reproducibility and stability, fast response, and low hysteresis made the pellet a suitable candidate for humidity sensing. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011