Toward Eco-friendly and Tunable Flexible Sensors: Effects of Ionic Liquid Structure on BC/PEDOT Composites as Mechanoelectrical Transducers

Flexible and sustainable materials for electronic devices are receiving growing attention, particularly in applications requiring biodegradability, low environmental impact, and compatibility with unconventional substrates. Bacterial cellulose (BC) has emerged as a promising candidate due to its nanofibrous structure, mechanical robustness, and hydrophilic character. When modified with ionic liquids (ILs) and conductive polymers, BC-based membranes can beengineered to serve as functional components in devices such as sensors, transducers, and actuators. In this work, we investigate hybrid membranes composed of BC, one of four selected ionic liquids-l-ethyl-3-methylimidazolium tetrafluoroborate (EMIM BF 4), 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM BF 4), 1-ethyl-3-methylimidazolium bis( trifluoromethylsulfonyl)imide (EMIM TFSI), and 1-butyl-3-methylimidazolium bis(trifluoromethyl-sulfonyl)imide (BMIM TFSI)-and a surface coating of PEDOT:PSS. The aim is to explore the suitability of these materials for vibration sensing, with a particular focus on their thermal behavior and electrical response. Here, we present the results of a comparative thermogravimetric analysis (TGA) to evaluate the thermal stability of the individual components and their combinations. In addition, preliminary mechanoelectrical tests are performed to assess the feasibility of the composites as functional sensor layers. While no complete sensor device is characterized in this study, the results provide useful insight into material interactions and guide further development of BC-IL-polymer systems for biodegradable electronics.