Applying Long-lived Metastable States with Switchable Functionality via Kinetic Control of Molecular Assembly - a Programme in Functional Materials

One of the most important current areas in chemistry is developing new materials that are able to respond rapidly and
reliably to changes in local environment, and send out signals that let us know what is happening. These "smart" materials can be used as sensors in a wide range of situations and are used in many aspects of modern life, from press-on patches to take a patient's temperature to solid-state electronic components in modern televisions. The clever chemistry used to develop such materials can help make materials with just the right property for the right situation - they can be made tuneable. The chemist aims to produce new, smart, responsive materials to be manufactured into useful devices for real applications. To produce new, better, more energy efficient materials that can benefit UK manufacturing and keep the UK at the forefront of technological developments, we need to find new ways of controlling the properties and functions of molecules to produce "even smarter" materials. This proposal aims to do just this, using a new way of tuning the properties of materials.
Most smart materials operate in an equilibrium state, while most complex systems, such as animals and humans, operate
in non-equilibrium states that are much more responsive to small changes in environment and can thus function in more
complex ways; indeed, if the human race operated in equilibrium, life would cease to exist as we know it! We need stimuli
to keep us alive we wish to take inspiration from ourselves in developing a new generation of smart materials, by applying
the ideas of "non-equilibrium" states to the development and operation of new materials. These will operate in different
ways giving access to new properties and functions.
Our new approach to designing new materials that operate in non-equilibrium conditions, uses "metastable" or excited
states - this means that we stimulate the material, for example by a light pulse, and by doing so we change the way in
which the chemical structure of that material delivers its properties. Effectively using excited states we can change the
behaviour of the electrons and hence the effect of the chemistry of a material without apparently changing its chemistry at all! Many current switchable smart materials must include regions of a different chemical or physical composition - these defects are very important for giving a material its properties, but produce a heterogeneous material - a good example is the "metamaterials" which physicists are developing. We will be able to introduce the same tuneable function but in chemically homogeneous materials, with real advantages for controlling their stability and performance.
To achieve this, we have to make significant advances across a range of areas, including designing the chemistry of
metastable switchable materials, generating excited states that give the desired change of property, controlling these
"metastable-excited states" and eventually to build these into useful devices for applications. Our proposal will allow us to develop ways of controlling the properties and functions of these metastable materials in ways that are not possible
currently.
There are many possible applications for these new materials including more efficient conductors and more miniaturisation
of devices that rely on electronics. We can also envisage engineering thin films that will provide each of the colours of the spectrum by simply changing the input voltage, allowing smart paints or smart fabrics whose colour could be chosen to suit mood or environment. We can also develop "active membranes" whose mechanical properties can be actively tuned, which will be useful in medicine and energy applications. In the longer term there is the prospect of developing
materials with a negative refractive index, whose special properties would mean that by switching on and off an electric
current, objects will apparently disappear and reappear!

This Programme will develop the fundamental underpinning research for a new family of functional materials. Scientifically, we will tackle the challenges of designing and making such materials, for which we must fully understand and control the generation and lifetime of the required metastable states. This will be tackled by the assembled diverse team at Bath and augmented by our many collaborative and consortia links. We will develop enhanced methods in synthesis, self-assembly, modelling and characterisation, that will have impact across the community in both science and technology, in addition to the potential impact of the materials themselves.

Initial Impact will be within the academic community, for whom our development of new methodologies, advanced experimental and computational techniques and, in essence, a whole new class of potentially functional materials will be of high value and interest. Without a doubt our early stage development within the Programme are at the fundamental end of our proposed range of research investigations, so this academic impact is likely to accrue very early in the Programme. Conceptually and practically, our harnessing of the untapped potential of long-lived metastable states for the production of functional chemically-inspired materials is moving onto new ground, and we expect this to influence the thinking and approach across the science disciplines, moving beyond chemists to physicists working in related fields (particularly metamaterials and other defect materials), materials scientists interested in functionality, and engineers interested in building smart devices into a range of production environments. Our Programme maps heavily onto important signposted (Directed Assembly, Frontier Manufacturing) and Grand Challenge areas (Healthcare (sensing, optical switching, smart membranes), Energy (new materials types, smart functional membrane technology), Environment (remediation, gas separation), Manufacturing (new materials types for low energy devices, bottom-up approaches to manufacturing) and Global Security (sensing) and so will help the academic community in engaging with these Challenges and recognising the diversity of approach that can be rewarding in meeting them.

Harnessing the power of metastable states in the way proposed is unprecedented, and the creation of such a radical approach to functionality will have potentially massive applied impacts in the medium to longer term. The developed materials will have applications in optics (for example by allowing tuneable refractive index with applications such as the invisibility cloak), pigments (offering flexibly tuneable and switchable colours), active membranes (gas separation, environmental remediation), sensing, etc. We will make leading-edge developments in an area where the UK is the potential world-leader and deliver real applications that will cement this - making UK the port-of-call for potential investment in basic R&D in these metastable materials.

On the slightly longer timescale our links with self-assembly and manufacturing offers the potential for cost-effective, optimised, materials production, while those with device manufacturers offer the potential to produce real device spin-offs from the programme. We will engage fully with industrial partners as the Programme evolves, moving from our initial "Cloud" model to more concrete interactions as our discovery programme feeds into materials development. We have a strong track record of engagement with industry - from SMEs to multinationals - and will benefit also from routes enabled by the University of Bath including specific Knowledge Transfer funding, KTP opportunities and support from the Research Office in exploring IP protection and commercialisation options.

Our research workers will receive training in a highly interdisciplinary, outward-looking, collaborative environment with extensive external links.