This combination provides a route to incredibly inexpensive, routine analysis of a vast array of analytes.  Recently, this group has developed a novel method for producing 3D printed optical sensors², which lowers the cost of such sensors even further and allows for their ready mass production.

This approach to optical sensor production is the focus of this PhD, in which existing optical sensors, such for CO₂ and O₂, will developed further and new optical sensors, for toxic gases (such as CO), fruit ripeness (such as aldehydes) and pH will be created.  The student will receive training in a wide range of techniques including: UV/Vis spectrophotometry, luminescence spectroscopy, digital photography and colour analysis, as well more traditional analytical and material characterisation techniques such as HPLC, GC, FT-IR, NMR, SEM, XRD, XPS and AFM. The successful candidate will interact with external collaborators, such as those from the environmental monitoring, healthcare and packaging industries. 

Professor Mills is the 2019 recipient of the RSC 2019 The Materials for Industry - Derek Birchall Award for his pioneering work on smart inks, pigments and extruded plastic technologies, with widespread applications across many industrial sectors.

For further information relating to this project, please contact Professor Andrew Mills via email.

References:

[1] Spectrophotometric and Digital Colour Colourimetric (DCC) analysis of colour-based indicators, Dilidaer Yusufu, Andrew Mills, Sensors and Actuators: B. Chemical, 2018, 273, 1187-1194.

[2] 3D printed O2 indicators, Dilidaer Yusufu, Ri Han and Andrew Mills, Analyst, 2020, 145, 4125-4129.

Frustrated Lewis pairs (FLPs) are combinations of Lewis acids and Lewis bases, prevented from the adduct formation by steric hindrance. Solutions of FLPs in non-coordinating organic solvents have been shown to contain low concentration of FLP encounter complexes, held together by weak interactions. In these encounter complexes, the proximity of Lewis acidic and basic sites leads to unusual reactivity: FLPs can activate hydrogen, in a manner similar to transition metal catalysis, but in the absence of transition metal. Other small molecules may also be activated, notably, recently reported was nitrogen activation.

Recently we discovered that the dissolution of FLPs in ionic liquids leads to enhanced encounter complex formation (Chem. Commun., 2018, 54, 8689) and to more elegant hydrogenation systems due to the absence of volatile organic solvent components. In this project, the student will study activation of small molecules, in particular activation of ammonia boranes to support a hydrogen economy, by FLP complexes generated in ionic liquids, and – more ambitiously – by designing and synthesising new ionic liquids materials that function as intrinsic FLPs.

For further information relating to this project, please contact Dr Gosia Swadźba-Kwaśny or Professor John Holbrey via email.

Mass-produced polymers, colloquially called plastics, have transformed our civilisation enabling the construction of light-weight, functional high performance materials and devices, in addition to ubiquitous, abundant and inexpensive single use items (such as cutlery and packaging). While we can (and should) strive to minimise single-use plastic and promote direct recycling and reuse to reduce the environmental impact (Fig 1) and promote sustainability, there are many areas where this is impractical or unfeasible, and alternative approaches including chemical recycling or repurposing are required.

Plastic waste can be recycled via several routes: depolymerisation to regenerate monomers, pyrolysis to low molecular weight chemical feedstocks, and gasification to syngas. In all cases, the most significant challenges related to the effects of contamination which can inhibit or deactivate traditional catalysts requiring redesign of catalysts. In this project, chemical recycling of waste plastics feedstocks will be investigated, developing novel, inexpensive, and robust acidic ionic liquid catalysts that can withstand the presence of inadvertent contamination and so overcome the major technical barrier to utilisation of waste plastics as chemical resources.

For further information relating to this project, please contact Dr Gosia Swadźba-Kwaśny or Professor John Holbrey via email.

Here the main drawbacks are the cost of electricity to run the process and the capital cost of the electrolyser. Use of renewable energy, such as wind power, which may be intermittent in nature and not easily added to the grid, can be used as a cheaper electricity supply and this can then be used to split water leaving the capital cost of the electrolyser to be considered. In certain cases, the membrane which separates the H₂ and O₂ in the electrolyser, is the most expensive component. One option is to use a membraneless electrolyser but then the H₂ and O₂ need to be separated separately.

Porous liquids are materials which contain soluble, permanent cavities in a solvent which is sufficiently large that it cannot access the cavities (Nature 2015, 527, 216-221; Chem. Sci. 2020, 11, 2077). The cavities (or pores) can then be tailored to selectively entrap a range of gas molecules.

This project aims to use these porous liquids in an electrolyser to separate out the O₂ in the electrolyser system, allowing the H₂ to be removed and stored at high pressures. The work will include the design and synthesis of porous liquids, analysis of their gas storage capacity and stability over repeated charging and discharging cycles and an evaluation of the porous liquid systems for efficiency, ease of application and cost.

For further information relating to this project, please contact Dr Jillian Thompson via email.