Sustainable Collagen Blends with Different Ionic Liquids for Resistive Touch Sensing Applications

Abstract

Considering the sustainable development goals to reduce environmental impact, sustainable sensors based on natural polymers are a priority as the large im plementation of these materials is required considering the Internet of Things (IoT) paradigm. In this context, the present work reports on sustainable blends based on collagen and different ionic liquids (ILs), including ([Ch][DHP], [Ch][TSI], [Ch][Seri]) and ([Emim][TFSI]), processed with varying contents and types of ILs in order to tailor the electrical response. Varying IL types and contents leads to different interactions with the collagen polymer matrix and, therefore, to varying mechanical, thermal, and electrical properties. Collagen/[Ch][Seri] samples display the most pronounced decrease of the tensile strength (3.2 ± 0.4 MPa) and an increase of the elongation at break (50.6 ± 1.5%). The best ionic conductivity value of 0.023 mS cm-1 has been obtained for the sample with 40 wt % of the IL [Ch][Seri]. The functional response of the collagen-IL films has been demonstrated on a resistive touch sensor whose response depends on the ionic conductivity, being suitable for the next generation of sustainable touch sensing devices.