Polymer chemistry is dominated by macromolecules with C-C, C-N and C-O backbones (for example: polyolefins, polyamines, polyesters). While these are both societally and technologically ubiquitous, they are also often persistent in the environment after they have been used. Polyolefins are particularly important in this regard as they are manufactured and used on an immense scale due to their exceptional chemical and mechanical stability. However, they are also very challenging to recycle back to the starting materials (alkenes) for the very reasons that make them so useful.
Replacing C–C polymer chains with B–N chains makes polyaminoboranes, –(H2BNHR)n–, that are isoelectronic with polyolefins but with potentially very different materials properties, due to electronegatively differences between C–C and B–N. However, the controlled synthesis of polyaminoboranes has, until very recently, been challenging. Very recent results from the Weller group (J. Am. Chem. Soc. 2021 in the press DOI: 10.1021/jacs.1c10888) has removed this bottle-neck through the development of simple, robust, and scalable catalyst systems to make polyaminoboranes on scale and with control from simple starting materials.
This now opens up an exciting opportunity to develop the materials chemistry aspects of these new polymers, for example as precursors to high performance main-group “BN”-type materials, and also investigate the upcycling (new materials) or recycling (making pristine polymer) of polyaminoboranes. This PhD project will do this, and is a joint one that brings together expertise in the Weller group (main group chemistry, catalysis, mechanism) with the Douthwaite group (materials processing, characterisation, and translation to use). This is a unique opportunity to be at the forefront of an emerging area of main-group polymer and materials science.
In this project you will use established catalytic systems, as well as developing your own, to synthesise a variety of targeted polyaminoboranes on a suitable scale for materials applications. You will then study how to use these to make new BN materials (thin films, fibres, aerogels, ordered porous materials, 3D-printable materials, precursors to hexagonal boron nitride, hydrophobic surfaces), and how these polymers can be chemically recycled or upcycled. The focus will be on scientific discovery and rigorous understanding, coupled with a strong trajectory to develop user friendly methods that are more widely applicable.
You will become an integral part of two research teams, who will help in supporting you in your challenging project. With the Weller group you will explore the catalytic synthesis, and recycling/upscaling, of polyaminoboranes. With the Douthwaite group you will explore materials processing and characterisation of the polymers made. A cycle of innovation will link the two, allowing for rapid progress to be made.
The ambitious objectives of this PhD are to develop robust routes to recyclable polyaminoboranes, and begin to realise their full materials exploitation. This would represent a breakthrough in the field, and you will be central to delivering this.
You will become expert in a wide range of techniques, that will allow you to develop skills in organometallic catalysis and materials chemistry for the synthesis of main-group polymers and materials, and their characterisation. At the end of the project you will have broad and deep expertise in a wide range of fundamental, and more applied, organometallic/inorganic materials chemistry techniques. There is also the opportunity to collaborate more widely with computational chemists (Stuart Macgregor, Heriot Watt), polymer chemists (David Haddleton, Warwick) and main-group materials chemists (Ian Manners, University of Victoria, Canada).
For more details about the research groups of Andrew Weller and Richard Douthwaite see:
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