TITLE: 'Electrospun PVDF Fibers: Brillouin studies and piezoelectric applications in Energy and Health'
AUTHOR: Didier Rouxel - Institut Jean Lamour-Université de Nancy (Francia).
WHEN: 2026-04-24. 12:00h
WHERE: Salón de Actos ICMM
ABSTRACT: Nowadays, alternatives to batteries are a growing topic of interest, related in particular to the environmental impact of electronic devices. For low power applications, energy harvesting through electroactive polymer based nanogenerators is one of the regarded routes. And among such polymers, Polyvinylidene fluoride (PVDF) is the most widely studied due to its good electro-mechanical coupling properties, high chemical stability, flexibility and biocompatibility. Electrospun film preparation allows for a variety of applications.
For the first time, micro-Brillouin spectroscopy was used for the mechanical characterisation of isolated PVDF electrospun fibres. A strong variation of mechanical properties was observed, depending of the ratio of solvent used for elaboration of the fibers, attributed to the presence of mesoporosities within the fibres, originating from the difference in solvent evaporation speed. Addition of fillers in the fibres lead to an slight increase of the c11 elastic constant, up to 4wt\% in content. Another important result was obtained by exploring the evolution as a function of temperature of the mechanical properties of electrospun PVDF fibres. An unexpected elastic anomaly was evidenced around 30°C, that we will discuss.
The piezoelectric performances of the materials were evaluated using a tapping-test bench conceived in the lab. Using this setup, it was possible to test the performances of the PVDF-composite fibres, and ensure its sensitivity to applied force and frequency changes. A sample device was chosen which achieved high output performance while maintaining good signal stability, reaching 60V of peak-to-peak voltage, and 60µA of peak-to-peak current. With an appropriate energy harvesting board, a demonstrator application of the device was proposed. The PVDF proved its practical ability to function both as a pulse sensor, and as a mechanical energy harvesting nanogenerator, showing a potential for integration into low-power, wireless health monitoring systems. Invited by: Rafael Jiménez.
