Enabling interfacial adhesion between conductive rubber and piezoelectric polymer for energy harvesting applications

The interest in energy harvesting technology is steadily growing in the field of self-powered wireless sensors for smart tires. In this work, the effect of the chemical adhesion between a piezoelectric material and an elastomeric electrode on the performance of the energy harvester for battery-less sensors has been experimentally investigated. A piezoelectric polymer PolyVinyliDene difluoride (PVDF) file and Natural Rubber (NR) filled with conductive carbon black were considered as energy harvester components. The adhesion between the interfaces was improved through surface modification of the PVDF film by introducing oxygen functional groups via a plasma treatment and further modification with a thiocyanate silane. The successful surface modification of the PVDF film was affirmed by x-ray photoelectron spectroscopy. T-peel and fatigue tests showed durable and stable adhesion between PVDF and conductive elastomer, confirming that the silane can effectively bridge the two components. Experimental results revealed also that the chemical bond between these two components significantly affects the amplitude of output voltage. The harvester is estimated to sufficiently power a reference tyre sensor, producing 28 μW cm−2.