Electrospinning poly(l-lactic acid) piezoelectric ordered porous nanofibers for strain sensing and energy harvesting

We reported ordered porous poly(l-lactic acid) (PLLA) piezoelectric nanofibers on comb electrode for both a stain sensing and human joint motion energy harvesting. The ordered porous PLLA piezoelectric nanofibers were fabricated using electrospinning equipment. The reason for choosing this equipment was that the electric dipole component along the main carbon chain of PLLA polymer nanofibers can be polarized along the direction of alignment during the process of a direct current electric field electrospinning. When the ordered porous PLLA piezoelectric nanofibers prototype is motioned with a bending deformation, the produced charges on PLLA piezoelectric nanofibers will flow out through comb electrode for a measurement. It demonstrated that an open-circuit voltage and short-circuit current with a strain deformation angle 28.9° could reach 0.55 V and 230 pA, respectively. It concluded that the prototype could be used as a stain sensor due to the good linearity of a short-circuit current and an open-circuit voltage. Finite element calculating software (COMSOL Multiphysics) was adopted to evaluate the bending deformation and electrical performance of PLLA nanofibers. At the end, we also proved that the produced prototype worked well for harvesting human joint motion energy with a maximum peak power 19.5 nW.