Precision synthesis using nanoscale electrochemistry

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The emergence of nanoscience and technology is regarded as a modern day industrial revolution, stimulating significant scientific, economic, and social development. The revolution is driven by the fabrication of functional nanomaterials which are materials with length scales on the order of billionths of a metre (1 - 100 nm = 10-9 - 10-7 m) in at least one lateral dimension. At surfaces/interfaces, these are typically achieved using probe-based methods to print materials in 2D/3D. However, in priority research areas such as healthcare (e.g. drug delivery, diagnostics, etc.), and energy-related technologies (Li-ion batteries, supercapacitors, etc), there is sustained demand for smaller dimensions, higher resolution and better properties, which will be met through the development of probe-directed organic, macromolecular and supramolecular synthesis at surfaces. When chemical reactions proceed with the exchange of electrons between reagents/reactants, i.e. oxidation and reduction, the reaction progress can be controlled using an electrochemical stimulus i.e. by applying a voltage or current to switch reactions on and off. Electrochemical nanoprobes have been developed that can precisely control their position relative to a surface by monitoring perturbations in electrochemical signals and surface activity. Furthermore, they can be loaded with molecules the flux of which can be precisely controlled using an electric field. In this project we will initiate the combination of this frontier in the electrochemistry with frontiers in synthesis (nanoscale, spatial and temporal control, external stimulus) by investigating the use of electrochemical nanoprobes as reaction vessels to simultaneously control the location and progress of specific reactions at surfaces ranging from conducting (electrodes) to biological (cells) substrates. Specifically, chemical reactions that lend themselves to electrochemical control on a macroscopic scale such as electrochemically mediated/triggered radical, cationic and ring-opening polymerisation will be translated to the nanoscale. The concept of controlling 3D surface topography will be elaborated by combining electrochemically mediated synthesis with electrochemically assisted self-assembly (EASA), which when confined to the meniscus of an SECCM nanopipette will enable precise control over surface morphology and topography. Compared to existing technologies this will enhance 3D resolution and expand the structural, morphological and functional diversity of accessible nanomaterials. Long-term, the outcomes of this research will reach a broad scientific, industrial and socio-economic audience finding impact in areas such as nanotechnology and healthcare. The nanoscale dimensions, high resolution and broad chemical/functional scope allude to a possible bottom-up, direct-write approach to nanolithography, a method widely used to fabricate micro- and nano-electronic components that power the electronic devices that dominate our daily lives. Whilst, in healthcare there are potential applications in micro-/nano-array diagnostics, personalised wearable technologies, tissue engineering and cell therapy. It is expected that these applications will sustain the programme of research in the long-term, well beyond the tenure of this fellowship.