Size dependent relative humidity sensing of Ag/PVP nanocomposites by direct optical transmission method

Ag particles having different sizes (A1 A2 A3 A4 and A5) were in situ synthesized by using chemical route in 0.01M PVP. Size dependent humidity sensing was studied by direct optical transmission method. Structural characterization and elemental analysis of the synthesized materials is carried out using UV-Visible, DLS and Impedance spectra. Change in impedance spectra with reaction time gave explanation about structural changes in polymer nanocomposite. Samples taken out after reaction time of 30 min show more sensitivity during wide humidity sensing range (2–94 % RH) i.e. 5.37 (78–94), 2.31 (77–59) and 0.32 (2–58) mv/% RH. A1samples have low hysteresis with response and recovery time of about 24 and 33 sec respectively. They have shown good repeatability over 7 cycles and reproducibility for two samples.