Direct-Ink-Writing of Electroactive Polymers for Sensing and Energy Storage Applications

Considering the high levels of materials used in the fields of electronics and energy storage systems, it is increasingly necessary to take into consideration environmental impact. Thus, it is important to develop devices based on environmentally friendlier materials and/or processes, such as additive manufacturing techniques. In this work, poly(vinylidene fluoride) (PVDF) and poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) are prepared by direct-ink-writing (DIW) by varying solvent evaporation temperature and fill density percentage. Different morphologies for both polymers are obtained, including dense films and porous membranes, as well as different electroactive beta-phase content, thermal and mechanical properties. The dielectric constant and piezoelectric d(33) coefficient for dense films reaches up to 16 at 1 kHz and 4 pC N-1, respectively for PVDF-HFP with a fill density of 80 and a solvent evaporation temperature of 50 degrees C. Porous structures are developed for battery separator membranes in lithium-ion batteries, with a highest ionic conductivity value of 3.8 mS cm(-1) for the PVDF-HFP sample prepared with a fill density of 100 and a solvent evaporation temperature of 25 degrees C, the sample showing an excellent cycling performance. It is demonstrated that electroactive films and membranes can be prepared by direct-ink writing suitable for sensors/actuators and energy storage systems.

Automated summary

This study demonstrates the preparation of electroactive films and membranes using direct-ink writing technology for sensors/actuators and energy storage systems. By varying solvent evaporation temperature and fill density percentage, different morphologies and properties of PVDF and PVDF-HFP materials were obtained, showing potential for environmental-friendly device development in electronics and energy fields.