Characterization of Nanoporous Polyvinylidene Fluoride (PVDF) Sensors Under Tensile Loading

A Polyvinylidene Fluoride (PVDF) sensor with integrating nanoporous structures was developed and fabricated to improve its piezoelectric effect. The sensor samples with different porosities ranging from 3.3% to 42.0% were made. The porosity effect on the piezoelectric coefficient d₃₁ of the sensors was studied under tensile loading. The results showed that the d₃₁ value increased from ∼21.3 pC/N to ∼51.3 pC/N as the porosity increased from 3.3% to 23.7%. With a further increase in porosity, the d₃₁ value had a considerable declining trend. The optimal porosity value was determined to be 23.7% as the sensor exhibited the strongest piezoelectric effect at this point. Meanwhile, a cyclic load was applied to the sensors to investigate their sensing effect and the results indicated that the sensors can properly detect a dynamic load ranging from 0 to 10 N. It was also found that the voltage output produced from the sensors significantly changed with the porosity and the sensor with 23.7% porosity showed the best sensing performance, which was in an agreement with the piezoelectric coefficient d₃₁.