Multi-sensing properties of hybrid filled natural rubber nanocomposites using impedance spectroscopy

In this work, natural rubber nanocomposites filled with carbon black and carbon nanotubes were prepared via latex mixing, and their applicability as multisensory devices were analyzed through Electrochemical Impedance Spectroscopy (EIS). Static and cyclic strain sensing was performed until 300% strain and the piezoresistivity, piezo-impedance, and piezo-capacitance were evaluated. The results indicated that impedance magnitude could be used instead of calculated resistivity, especially in lower and medium strain ranges. In higher strains, the capacitive behavior turns predominant, and the piezo-capacitance becomes the ideal parameter to be measured providing higher sensitivities as the gage factor (GF) reaches similar to 41.82 in 300% strain. The solvent sensing also showed that piezo-capacitance is a better measure than piezo-impedance, with a quicker response time and greater sensibility. This study demonstrated that using EIS in strain and solvent sensing of rubber nanocomposites can offer more detailed information about complex transport mechanisms and improve the sensitivity, linearity, and response time of elastomeric sensors.