Electrical and Apparent Compressive Response of Silver-Loaded Honey–Gelatin Soft Composite Membranes

Abstract

Honey–gelatin–water composite membranes containing silver microparticles (SmPs) are investigated as soft pressure-responsive materials with potential applications in low-pressure sensing, including biomedical monitoring, and in tunable capacitive components. Three compositions, with nominal volumes of loose SmP powder of up to 3cm3, are prepared to determine how silver loading affects their electrical and apparent compressive response. The membranes are characterized by optical microscopy, XRD, and SEM and are placed between electrodes in a parallel-plate configuration. Capacitance and parallel resistance are measured at 1kHz under applied pressures up to 2.25kPa, and the corresponding admittance components and apparent compressive parameters are calculated from these measurements. It is shown that SmP loading increases the capacitance and reduces the resistance. Between the SmP-free and most highly loaded membranes, the zero-pressure capacitance increases by more than four orders of magnitude, whereas the resistance decreases by approximately a factor of 40. Applied pressure further increases the capacitance and decreases the parallel resistance of all membranes. The apparent strain increases approximately linearly with pressure and is greater in the SmP-loaded membranes, whereas the apparent modulus decreases as the SmP content is increased. The structural and electrical results show that SmP content and the associated heterogeneous microstructure influence both the electrical and apparent compressive response.