3D Printable and Biocompatible Iongels for Body Sensor Applications

LUQUE, GISELA C.; PICCHIO, MATÍAS L.; MARTINS, ANA P. S.; DOMINGUEZ?ALFARO, ANTONIO; RAMOS, NICOLÁS; DEL AGUA, ISABEL; MARCHIORI, BASTIEN; MECERREYES, DAVID; MINARI, ROQUE J.; TOMÉ, LILIANA C.

Advanced Electronic Materials

Wiley

Año: 2021

2199-160X

Soft-ionic materials with biocompatibility and 3D printability are needed todevelop next-generation devices to interface between electronic and biologicalsignals. Herein, thermoreversible and biocompatible ionic liquid gels or iongels, which can be processed by direct ink writing are reported. The iongelsare designed by taking advantage of polyvinyl alcohol/phenol interactionsto gelify biocompatible cholinium carboxylate ionic liquids. The obtainediongels are stable, soft, and flexible materials (Young modulus between 14and 70 kPa) with high ionic conductivity (1.8 × 10?2 S cm?1). Interestingly, theypresented thermoreversible properties with gel?sol transitions ranging from85 and 110 °C, which allows the iongel processing via direct ink writing 3Dprinting by material extrusion at temperatures over its transition. These 3Dprintable iongels are integrated into a variety of body sensors applications,namely pressure sensors, motion sensors and electrodes for electrophysiological recordings. The iongels are used as pressure sensors with a sensitivityof 0.1 kPa?1, ten times higher than that of others similar materials reportedso far; showing its ability to detect human motion. Furthermore, the iongelsshowed excellent performance in electrodes for electrocardiography (ECG)recording, presenting good stability over time with electrocardiographicwaves maintained their typical shape even after weeks.