Printable Ionic Liquid-Polymer Hybrid Materials for Sensors and Bending Actuators

The rapid digitalization of the society and the economy, associated to concepts like Internet of Things and Industry 4.0 is boosting the increasing implementation of sensors and actuators. Printing technologies are called to play a major role in this field, as it allows the necessary steps towards sustainable digitalization.<br/>In recent years, printable smart materials incorporating ionic Liquids (ILs) [1] have garnered significant attention due to their ability to develop smart flexible and conformable devices, including sensors, actuators and energy harvesting devices, among others. Those approaches rely on properly tunning the functional properties of the ionic liquid by adequate selection of anion and cation, on the compatibility between IL and polymer and the printability of the developed inks.<br/>In this work, different IL have been used for the development of functional inks and have been applied for the development of force and deformation sensors, bending actuators and optically responsive systems.<br/>[Bmim][N(CN)₂] has been use to optimize the piezoionic response of different polymer matrices, including electroactive (PVDF) and biobased (e.g. sodium alginate) ones; [C₄mim] [FeCl₄] Has been used to induced magnetoelectric sensing and bending actuation response and [Bmim]₂[NiCl₄] for thermochromic, thermoelectric and humidity sensing, response within a PVDF polymer matrix. Finally, optically responsive materials are obtained based on [Bmim][Eu(tta)₄] and Na[Eu(tta)₄].<br/>The design rules and processing strategies will be discussed together with a complete physical-chemical characterization of the printed materials, their functional response and device demonstration.<br/><br/>Acknowledgments<br/><br/>Portuguese Foundation for Science and Technology (FCT): UID/FIS/04650/2020, UID/QUI/00686/2020, UIDB/50006/2020, UIDP/50006/2020, 2022.05932.PTDC, PTDC/FIS-MAC/28157/2017, NORTE-01-0145-FEDER-000084, PTDC/CTM/4304/2020, UIDB/00616/2020 and UIDP/00616/2020, and Investigator FCT Contract 2020.02915.CEECIND (D.M.C.). B.D.D. Cruz, for PhD grant 2022.13287.BD. Basque Government Industry Department under the ELKARTEK program. Advanced Materials program, supported by MCIN with funding from European Union NextGenerationEU (PRTR-C17.I1) and by The Basque Government under the IKUR program.<br/><br/>[1] Ionic Liquid–Polymer Composites: A New Platform for Multifunctional Applications; D. M. Correia, et al, 30, 24, 2020, 1909736