All-organic shell-core PVDF/PMMA composite fiber films with enhanced piezoelectric performance for flexible sensing and energy harvesting

The demand for self-powered sensing technology and energy harvesting system necessitates high-performance and flexible piezoelectric materials. This paper presents a novel approach utilizing coaxial electrospinning to fabricate all-organic PVDF/PMMA piezoelectric fiber films with a shell-core structure. The resulting fiber films, cut into 2 x 2 cm(2) square pieces and hot-pressed every three pieces, demonstrate enhanced piezoelectric properties while retaining high flexibility. The interaction between the -C=O bonds in the PMMA polymer and the -CH2 in PVDF promotes the arrangement of F atoms in PVDF, enhancing the content of the piezoelectric active phase. Additionally, the coaxial electrospinning process fosters vertically oriented hydrogen bonds between PVDF and PMMA, augmenting cross-linking and improving mechanical properties. Notably, when the PVDF to PMMA layer volume ratio is 5:1, the piezoelectric coefficient (vertical bar d(33)vertical bar) of the composite fiber film exhibits a significant 60% increase from 10 pC N-1 in neat PVDF to 16 pC N-1. This research holds substantial promise for applications in self-powered sensing and energy harvesting piezoelectric materials.