To start this project, we focused on the development of poly(ionic liquid)s combining cationic polyesters backbones. Then, and in addition to what was initially projected, alternative synthetic pathways were proposed in order to obtain other poly(ionic liquid)s and ionic liquids having biodegradability and biocompatibility potential. In particular, novel ionic liquids and poly(ionic liquid)s combining neurotransmitters were proposed, considering their great interest for ion pump applications. On the other hand, new functional polymers and biocompatible/biodegradable ionic liquids were also synthesized to be used as precursors in the preparation of semi-solid iongels for bioelectronic devices. Although the small deviations and additional work performed, the key objectives were achieved and optimized protocols for the reproducible synthesis of several monomers and polymers were obtained.
The structural characterization of all the prepared materials was mainly investigated by NMR and FTIR. In order to better understand different structure-property relationships, complete characterization data was obtained by investigating the thermal behaviour, mechanical stability, rheological behaviour and morphology of the prepared materials. Biocompatibility tests and degradation studies were also carried out.
The use of the prepared ionic liquid-based materials in bioelectronic devices was investigated, particularly in electrodes for cutaneous electrophysiological recordings. Free standing conductive iongel materials were prepared and their ionic conductivity with temperature and time were studied. Furthermore, a pressure and strain sensor platform was fabricated to demonstrate the sensory capability of the materials. Artificial skin devices with the ability to sensitively detect stimuli, such as mechanical force and temperature changes, have been intensively investigated for applications in soft robotics and bioelectronics.
Finally, ionic liquids and poly(ionic liquid)s combining neurotransmitters were used to develop a new method to significantly limit drug leakage from electrophoretic drug delivery devices, which is one of the major challenges these bioelectronic devices are facing. It is worth mentioning that this novel approach can be universally applied to any device architecture to extend the lifetime of drug delivery implants while making them safer for chronic implantation.
During this project, the ER published 8 research articles (Membranes 2018, 8, 124; Ind. Eng. Chem. Res. 2019, 58, 2017-2016; Sep. Purif. Technol. 2019, 222, 168-176; Ind. Eng. Chem. Res. 2020, 59, 308-317 in I&EC Research 2019 Class of Influential Researchers Special Issue; Membranes 2020, 10, 46; ACS Sustain. Chem. Eng. 2020, 8, 5954−5965; Macromol. Biosci. 2020, 2000119; ACS Sustainable Chem. Eng. 2020, 8, 7087−7096) and 1 review article (J. Phys. Chem. B 2020, DOI: 10.1021/acs.jpcb.0c04769). In addition, 1 research article (Advanced Science) and 1 review (Prog. Mat. Sci.) were submitted and are under review. Two more manuscripts with the remaining results of the project are under preparation.
The ER attended two international conferences to present 2 posters and 1 invited lecture. The ER also gave an invited seminar and participated in 2 outreach activities.
