Most natural organisms show fascinating mechanical versatility when interacting with their environments. Stiffness tuning in nature is used as a powerful tool to combine the load carrying functionality of rigid structures with compliance and adaptability. A remarkable example of stiffness tuning can be seen in echinoderms, such as sea cucumbers, where the mechanical stiffness can change by a factor of 10 in less than 1s. Human-made structures are normally designed to meet a specific load carrying requirement. To add other functionalities, additional components are often required; these increase the total weight and cost of the structure and consequently cause limitations in performance, efficiency and safety. Therefore, embedding sensing, actuation and control within a structure is highly desirable. Inspired by stiffness tuning in natural organisms, various synthetic materials have been developed in recent years for active structural control. However, achieving significant stiffness reduction in a short time frame with minimum power requirements but without undermining the load carrying capacity of the structure remain as some of main challenges. In this proposal, we aim to tackle these challenges by exploiting recent advances in optoelectronics and nanotechnology to design, manufacture and evaluate a nano-structured interconnected metallic network embedded in a thermoplastic layer. This layer will be then employed, as an active interface, in a conventional multi-layered structure. Upon activation, it will provide rapid structural control and impact protection capabilities. We will use a combined experimental and numerical approach to investigate the electro-thermo-mechanical response of this interface. Understanding the main physical obstacles that limit the response time and the fundamental parameters controlling the stability and the failure of this interface under harsh electro-thermal loading will help us to better engineer this interface at the micro level to meet the fast response and low power requirements. This new understanding will accelerate the technology readiness level of active structural control technology to be used in future multi-functional and smart structures. This technology has a wide range of application in robotics, morphing and deployable structures, active damping and active impact protection. As a potential representative technology, we aim to employ this active interlayer in laminated glass windscreens for automotive vehicles. Application of this transparent active interface in windscreens will help protect vulnerable road users against head-related injuries and is believed to be a step change toward designing more pedestrian/cyclist-friendly vehicles. To motivate the development of this technology, the University of Surrey is partnering with Pilkington, a member of the NSG group, which is one of the world's largest manufactures of glass and glazing products for architectural, automotive and technical glass sectors to manufacture and test this active transparent interlayer for application in automotive windscreens.

It has been shown that large office buildings waste 20-40% of their energy on air-conditioning to cool down the building as a result of the sun. This is highly inefficient and has an impact on the environment. One way that has been proposed to tackle this problem is the use of Smart Windows. These windows are comprised of chromic materials that change to a dark colour upon the application an external stimulus. The change in colour results in high energy UV light that heats up the building being filtered out, thus reducing the need for air-conditioning. It is predicted that these technologies will save 20% on their energy bills, as the buildings will not heat up as much from the sunlight. However, so far this transparent-to-dark colour has been difficult to achieve. Suitable materials for Smart Glass that can change colour can be metal-based, organic-based or a hybrid of the two. Metal-based chromics are already used in displays and diagnostic tests. However, precious metals (Au and Ag) used in these high-end technologies is a rapidly running out resource, and are often difficult and dangerous to mine, and their use relies on countries cooperating well with each other. The processing of metals such as Cd, Lb, U and Cs has huge environmental consequences and the disposal of them leads to toxic and nuclear waste which has devastating effects on the workers, neighbouring villages and wildlife. Any metals that can be replaced with organic alternatives have a huge benefit to health, the economy and the environment. Organic materials are generally easier to process and can be synthesised on a larger scale. We have found a molecule based on a functionalised naphthalene diimide that when self-assembled in water shows great promise to be used in such applications. From proof of principle data we have collected, the assembled material can undergo a reversible transparent to black transition by applying a small voltage to the sample. This transition is quick and can be cycled at least 100 times without loss of colour intensity or response time. However, this system needs optimising to be able to fulfil industry standards, for example stability over 1000 cycles, reducing the speed of response of both transitions and the uniformity of colour across the device. We aim to do this with this proposal to make the organic alternative to metal systems competitive to use in the Smart Window technology.

Material architectures with pores on the 5 - 50 nm length scale offer distinct opportunities for chemo- and biosensing applications. Capillary condensation, i.e. the filling of pores with condensed liquid from the vapour phase, is highly dependent on the pore size and relative humidity. Efficient trapping of target analytes relates to a combination of adequate surface interaction and control over spatial confinement. The aim of this research proposal is to build porous materials with unprecedented functioning in humidity and biomedical sensing through the structural control offered by the use of block copolymer (BCP) co-assembly. BCPs are macromolecules that are composed of chemically dissimilar building blocks, which are linked by covalent bonds. Solvent evaporation leads to phase separation into nanoscale morphologies, which can be controlled by the molecular design of the BCPs. In a co-assembly approach, BCPs are used as sacrificial host to structure direct inorganic guest material. After structure formation, the organic material is removed to reveal a porous inorganic network. Conceptually, this approach allows to systematically vary and control key parameters of porous thin films, such as porosity, pore size and dispersity as well as the pore architecture, by modifications to the molecular building blocks and processing conditions. In the course of the proposed study, parameters that govern the pore size and dispersity will be elucidated and general effectiveness of BCP-derived porous materials evaluated on two different sensing platforms, namely humidity and biomedical sensing. In humidity sensing, the fabrication of transparent material architectures will be pursued that allow accurate determination over the full humidity range via capacitative means, offering an integrated route to responsive glazing components for automotive and building applications. Findings will be implemented in a windscreen prototype with responsive anti-fogging control. In the light of the gradual extinction of the internal combustion engine towards electrified mobility where heat is no longer abundant and thus a significant burden to the energy consumption, such technology will offer widespread impact. For biomedical sensing, the trapping of target analytes in porous networks will be studied for a number of candidates whose quantification is important in therapy, e.g. viruses, therapeutic antibodies, exosomes or microRNA. Applicability of effective trapping and the envisioned superior pore size control will be implemented in novel types of biosensors that allow detection by changes in electrochemical currents associated to a blockage of the pores. Successful proof-of-principle will stimulate the development of low-cost handheld diagnostic devices in point-of-care applications to improve therapeutic outcomes at minimal side-effects.

Dye-sensitized solar cells (DSC) can be described as a form of "artificial photosynthesis" because, in both cases, light is harvested by a pigment (chlorophyll in photosynthesis or a synthetic dye in DSC). This is interesting because photosynthesis is ~5% efficient in terms of the incident light energy (i.e. photons) captured to the energy in the photosynthetic by-products. Despite this apparently low efficiency, photosynthesis has supported the planet's biosphere for aeons. One reason for this is the huge amount of sunlight which reaches the Earth's surface every day. This has been estimated to be ~6,000x more than annual global energy consumption despite the growing global population using huge amounts of energy. Given that the sun will last for billions more years, sunlight is vastly more abundant than any other energy source currently available. In this context, if we use 10% efficient PV, using only 0.2% of the Earth's surface would meet energy demands whilst releasing only trace greenhouse gases during production and none during operation. This will slow the accelerating pace of fossil fuel related climate change. Whilst PV uptake has increased hugely recently (~11GW in UK and >225GW globally), this still represents a tiny fraction of current energy demand; the question is why? Crystalline Si PV currently dominates the market (~90%) but is heavy, rigid and is usually made from batch-like processes into limited product forms (rectangular, encapsulated, glass panels). And despite these products being available for many years, they are still bolted onto frames attached onto existing roofs with wires often running across open roof-space. They do not fit, they are a "bolt-on" solution. This research will develop PV which can be printed by continuous (roll-to-roll, R2R) processing. Because R2R is faster than batch processing, it will reduce manufacturing costs but increase the amount of product which can be made. R2R product can also be made to any length or width which will revolutionise PV product form. Perhaps most importantly, by varying the PV substrate, this will enable PV to be fully integrated into roof/wall panels or windows. This will drastically reduce installation and balance of systems costs (i.e. PV panel mounting system, DC/AC power inverters, wiring, switches, battery storage) which make up almost half of the cost of most PV installations. DSC technology is already in commercial production (www.gcell.co.uk) and is already known to be suitable for R2R processing. In addition, DSC raw materials are non-toxic and abundant. Whilst DSC device lifetimes >25,000h have been reported (equivalent to ~25y operation), the liquid electrolytes used can leak and are corrosive to some metals which increases substrate costs. This proposal will exchange this liquid electrolyte for a solid, charge carrier to make solid state DSC (ssDSC) devices to avoid these issues. Whilst ssDSC have been made before, it has been difficult to control their construction because this involves depositing 2 thin layers of different chemicals onto porous metal oxide particles in a porous film. The resulting inconsistent layer coverage causes energy losses which limits device efficiency. To overcome this, we will use self-assembling molecules and computer modelling to explore surface chemistry/structure to speed-up the research. Thus, we will design dyes and charge carriers to behave like "self-parking cars in a car park" and move to the correct position before fixing themselves in place. Then, by controlling the self-assembly process, we will add multiple dyes into the device to increase light harvesting to improve device efficiency to reduce pay-back times; i.e. the time when the customer has saved enough money on their energy bills to pay off the system purchase costs. By combining computer modelling and experiment, we will cut design to manufacture times up to 10-fold by reducing the number of material modification cycles required.

The FINESSE NanoBio team is proposing a new UK capability in imaging, cross-sectioning and patterning materials that are traditionally very difficult to examine at the nano and sub-nanometre scale without seriously effecting their structure or behaviour. It is important that the UK is placed at the forefront of this research, enabling start-ups, SMEs and large companies to drive innovation and growth with stronger underpinning scientific understanding. To address this, the team is requesting funding for a customised Zeiss NanoFab tool that consists of: 1. An ultra-high precision imaging capability (sub 0.5 nm) of conductive and non-conductive samples 2. An ultra-high precision patterning and TEM sample preparation capability (2 nm) of the same range of samples 3. A cryogenic sample handling system to enable imaging of biological materials and biological or fluid interfaces with materials and structures. The tool achieves this revolutionary performance by focusing a stream of helium ions onto the surface and measuring the subsequently released secondary electrons. Ions can also be used to remove material in their path for patterning or cross-sectioning materials. This system has three ion options, gallium for bulk removal, neon for additional polishing and cutting and helium for very careful polishing. This difference in behaviour is due to the lower mass of the ions. Direct writing of metals in 10nm feature sizes is also feasible with this system, which will enable electrical contacts to be fabricated to advanced functional materials to test, for example, their conductivity or electrochemical behaviour when making sensors. The requested support will have far-reaching impact through the projects and industrial partners of almost 50 research groups actively supporting this proposal in Cambridge, across 10 different Departments and 4 different Schools. This sphere of scientific influence is amplified by the strong support from 5 universities, 2 catapult organisations and 3 industrial network organisations, who represent an estimated 1500 companies. This incredible response by academics and industrial researchers means the facility will also drive new engagement and collaborations between these partiers and will foster collaboration, through for example the planned symposium and engagement events. The commissioning, access, outreach and management will be delivered by a small committee of experienced researchers and microscopy suite managers, with review and guidance from a larger steering group of EPSRC, industrial and academic partners to ensure fair access, an environment that fosters collaborations and postgraduate education.