This MSCA sought to develop to a solid contact sensor (or ion selective electrode) capable of detecting of different cations and anions for example lithium, sodium or chloride ions. The solid contact ion selective electrode is composed of a thin film membrane immobilised on an electrode surface such as carbon, Pt or Au. designed to make it capable of measuring the ion and its concentration. The membrane composition in this MSCA is usually made up of a polymer, plasticiser, ionophore, lipophillic salt and a ion to electron transducer for example an electron mediator based on osmium-containing complexes. In order to begin the evaluation of such a proposal, the Fellow had to develop an understanding of a new and different field of sensing previously unknown to the Fellow. Strict COVID-19 border rules within Australia resulting in a delayed start in the laboratory, it was essential that the Fellow developed a new skillset of creating of thin films for ion selective electrodes while garnering an understanding of the complex mechanisms. Within the Electrochemistry and Sensors group at Curtin University under the supervision of Professor Damien Arrigan, the Fellow developed significant expertise in the development and characterisation of thin film electrodes for use as ‘solid contact ion selective electrodes’.
Design and synthesis of osmium complexes was undertaken to target ideal characteristics such as hydrophobicity, reversibility and a given redox potentials between the reduction of oxygen present -0.4V and the oxidation of water above ~1.3V. Novel osmium complexes containing tetrazoles were synthesised. Novel osmium bound poymers were also targeted.
In order to test the suitability of the components within the membrane of the ion sensors, the Fellow investigated osmium-containing complexes and ubiquinone as potential ion to electron transducers within ion selective membranes. These membranes were then tested to determine their ability in sensing and measuring the concentration ions in aqueous solutions. Similar studies were undertaken where novel ion selective membranes made up of different polymers such as poly-ionic liquids and lipidure were used to determine their role to perform as the matrix and improve upon the biocompatibility. Solid contact sensors capable of detecting cations and anions were developed along with being to measure lithium in media similar to those at lithium brine deposit sites or perfluorooctanoic acid (PFOA), a "forever" chemical.
Results of this MSCA are reported in: (1) forthcoming papers on the study and research findings of different ion to electron transducers in ion selective membranes (2) forthcoming papers on the use different polymers as the matrix for ion selective electrodes (3) update of the project website and (4) presentations delivered at the 2022 Royal Australian Chemical Institute National Congress, 73rd Annual Meeting of the International Society of Electrochemistry, 35th Topical Meeting of the International Society of Electrochemistry and MLS Science Symposium held at Curtin University. The Fellow was invited by the Curtin Chemistry Club, the student union, to serve as a guest speaker. The purpose of this invitation was for the Fellow to deliver a talk and impart insights based on their career as a researcher and their experiences as a Marie Curie Fellow. Manuscripts that are currently under development using data collected during this fellowship will continue to achieve impact in coming years. Further discussions will be undertaken to determine the feasibility of the lithium-ion sensor and PFOA sensor developed in this MSCA.
The Fellow will maintain ongoing communication with both supervisors, Professor Leech and Professor Arrigan, concerning forthcoming publications. Manuscripts are presently in the drafting stage, with a plan to submit them to respected journals like Electrochimica Acta. In adherence to the 'open access' principles, all future publications will be made available on open access repositories, including ARAN(University of Galway), Zenodo, and/or Curtin University's espace. These publications will acknowledge their funding source, the EU MSCA (Marie Skłodowska-Curie Actions) Fellowship.
