Singapore

Automated, data-driven, and high-throughput experimentation is already revolutionising materials exploration and optimization. While great strides have been made in using this approach to optimize bulk properties of materials, functional nanomaterials remain poorly understood due to the complex and often non-linear relationship between material quality, geometry, and performance. In the first part of my fellowship, I have developed and demonstrated a unique experimental and statistical methodology to study individual nanomaterial performance at huge scale, with tens of thousands to millions of measurements. This has provided unique insight, robust statistical evidence, and industrially useful yield analysis. In the renewal period I will lead a world-class team to tackle urgent challenges in nanotechnology, namely scale-up for quantum photonic technologies, and ultra-high-throughput for novel materials. My program will draw on the expertise and capability of 10 international academic and industrial partners to maximise the impact of the research.

Wearable technologies such as smart watches, smart glasses or even smart pacemakers have caused a paradigm shift in consumer electronics with huge potential in areas such as healthcare, fashion and entertainment (e.g. augmented reality glasses). Currently these devices are still powered by batteries needing frequent replacement or recharging, a key challenge holding back wearable electronics. Thermoelectric generators (TEGs) are an attractive alternative to batteries as they can generate up to several 100 microwatts power from heat (e.g. radiated from the human body), are safe and long-lasting with zero emissions. Current TEGs however are plagued by low efficiencies, high manufacturing costs, and are fabricated onto rigid substrates which makes it difficult to integrate them into many applications that require conformal installation. There is therefore considerable interest in the fabrication of flexible TEGs that can harvest energy from body heat for wearable applications and other heat sources. This project seeks to develop a new generation of thermoelectric (TE) hybrid materials for flexible TE energy harvesting applications by combining inorganic materials with controlled 3D nanostructures and organic conducting polymers (OCPs). The materials have not been realized to date and will be optimized to yield enhanced TE power factors (PFs).

Liquid infused surfaces (LIS) are a novel class of surfaces inspired by nature (pitcher plants) that repel any kind of liquid. LIS are constructed by impregnating rough, porous or textured surfaces with wetting lubricants, thereby conferring them advantageous surface properties including self-cleaning, anti-fouling, and enhanced heat transfer. These functional surfaces have the potential to solve a wide range of societal, environmental and industrial challenges. Examples range from household food waste, where more than 20% is due to packaging and residues; to mitigating heat exchanger fouling, estimated to be responsible for 2.5% of worldwide CO2 emissions. Despite their significant potential, however, to date LIS coatings are not yet viable in practice for the vast majority of applications due to their lack of robustness and durability. At a fundamental level, the presence of the lubricant gives rise to a novel but poorly understood class of wetting phenomena due to the rich interplay between the thin lubricant film dynamics and the macroscopic drop dynamics, such as an effective long-range interaction between droplets and delayed coalescence. It also leads to numerous open challenges unique to LIS, such as performance degradation due to lubricant depletion. Integral to this EPSRC Fellowship project is an innovative numerical approach based on the Lattice Boltzmann method (LBM) to solve the equations of motion for the fluids. A key advantage of LBM is that key coarse-grained molecular information can be incorporated into the description of interfacial phenomena, while remaining computationally tractable to study the macroscopic flow dynamics relevant for LIS. LBM is also highly flexible to account for changes in the interface shape and topology, complex surface geometry, and it is well-suited for high performance computing. The developed simulation framework will be the first that can fully address the complexity of wetting dynamics on LIS, and the code will be made available open source through OpenLB. Harnessing the LBM simulations and supported by experimental data from four project partners, I will provide the much-needed step change in our understanding of LIS. The expected outcomes include: (i) design criteria that minimise lubricant depletion, considered the main weakness of LIS; (ii) new insights into droplet and lubricant meniscus dynamics on LIS across a wide range of lubricant availability and wettability conditions; and (iii) quantitative models for droplet interactions on LIS mediated by the lubricant. These key challenges are shared by the majority, if not all, of LIS applications. Addressing them is the only way forward to better engineer the design of LIS. Finally, the computational tools and fundamental insights developed in the project will be exploited to explore two potentially disruptive technologies based on LIS, which are highly relevant for the energy-water-environment nexus in sustainable development. First, I will investigate application in carbon capture, exploiting how liquids can be immobilised in LIS with a large surface to volume ratio, in collaboration with ExxonMobil. More specifically, liquid amine-based CO2 capture is an important and commercially practised method, but the costly infrastructure and operation prohibit its widespread implementation. Excitingly, LIS may provide a solution to a more economical carbon capture method using liquid amine. Second, motivated by the current gap of 47% in global water supply and demand, as well as environmental pressure to reduce the use of surfactants, I will examine new approaches to clean in collaboration with Procter & Gamble. The key idea is to induce dewetting of unwanted liquid droplets on solid surfaces using a thin film of formulation liquid, thus introducing wettability alteration more locally and using much reduced resources.

The greatest advance in magnetic technology in the last 20 years has been the development of "nanomagnetic" devices, magnetic systems with dimensions as small as ten billionths of a metre. The most common examples of this are found in computer hard-disk drives, where both the storage media and the sensors used to read data back are nanomagnetic in nature. The prevalence of modern personal computers means that the vast majority of homes and businesses in the United Kingdom, and indeed in much of the developed world, are now in some way dependent on nanomagnetic technology. Many other nanomagnetic devices are also being developed including magnetic memory devices, magnetic logic devices, microwave resonators, devices for medical diagnostics and magnetic sensors. These new technologies have the potential to be faster, cheaper and more efficient than their existing counterparts. For example, non-volatile magnetic memory chips will allow personal computers to be booted up into the exact state they were in prior to being shut down, removing the necessity of leaving systems switched on over extended periods. Similarly, magnetic bio-chips will soon allow complex medical tests to be performed at the doctor's surgery rather than in a laboratory, and at a faction of the price. In nanomagnetic systems understanding the effect of finite temperature is of critical importance, as thermal effects introduce disorder making it impossible to predict exactly how a device will behave. In hard-disks thermal excitations can cause data to be lost by reversing the individual "bits" that make up a file. This phenomenon is the primary factor that restricts the capacity of modern hard-disks. In other technologies the randomising effects of thermal perturbations make devices unreliable by making it impossible to predict the exact state a device will be in before and after an external operation is performed. Again, this lack of reliability is a leading factor in preventing new nanomagnetic technologies, and the social and environmental benefits they will bring, being available on the high street. Despite the huge technological importance of these "stochastic" effects they are poorly understood with most studies considering them only in a phenomenological or empirical fashion. To be able to understand and accurately predict stochastic behaviour in magnetic systems it is necessary to have a thorough knowledge of two parameters: the energy barrier, which determines how strongly a system is confined to a given state; and the attempt frequency, which determines how often thermal excitations try to alter the configuration of a system. Unfortunately neither of these parameters are accessible by standard measurement techniques, and hence they are neither well understood, nor characterised. In this fellowship I will use time, frequency and temperature resolved measurements, coupled with new numerical modelling techniques, to directly measure both attempt frequencies and energy barriers across a broad range of technologically relevant magnetic systems. These will include those for use in new hard-disk technologies, memory devices, information processing systems, novel sensors and microwave resonators. In doing this I will create the first comprehensive framework with which to a) understand, b) predict and c) mitigate the effects of stochastic behaviour in nanomagnetic devices. This will allow researchers and technologists to, at last, quantitatively predict how thermal perturbations will affect nanomagnetic devices, and understand how the problems they introduce can be overcome. There is currently an explosion of interest in developing new nanomagnetic technologies in both academia and in industry. This fellowship will be critical to ensuring that progress is not inhibited by a lack of understanding of stochastic magnetic behaviour, and that the great potential of nanomagnetic technology is brought to the high street.