Mechanics of Soft Aerosols

Soft matter science is a vast field; from liquid crystals to polymers, colloids to foams the research output is varied and often exciting. However, the intersection of soft matter systems and aerosol science has largely been unexplored. Many questions remain on the mechanics of soft matter aerosols interactions, namely how fundamental material properties of soft matter systems such as surface tension and viscoelasticity affect aerosols as they are created and interact with surfaces and each other. What conditions lead to soft matter aerosols adhering to a surface or breaking up or rebounding? And how do varying viscoelastic properties affect this? This project looks to answer these questions and more via probing the mechanics of soft aerosols via computational models of soft viscoelastic aerosol interactions as well as complimentary laboratory work with soft materials to test these models. Soft matter aerosols are particularly relevant given the Covid-19 pandemic, with soft respiratory droplets containing mucus, sputum and other soft materials being vectors for the SARS-CoV-2 virus. Research into the physics of soft aerosols could therefore give some input into several potential broader public health questions. For example, how valuable items such as masks and face shields are when faced with a soft aerosol containing Covid-19 and which materials are best to use for such items. Soft aerosols also crop up in engineering and industry problems, from efficient spray-painting processes to superheated sand impacting jet engines in deserts; knowledge of generic soft aerosol models may have applications in many places. Creating models of soft aerosols and testing these models from lab-created viscoelastic soft materials experimentally will be the main aims of this work.

Aerosol science has a significant impact on a broad range of disciplines, extending from inhaled drug delivery, to combustion science and its health impacts, aerosol assisted routes to materials, climate change, and the delivery of agricultural and consumer products. Estimates of the global aerosol market size suggest it will reach $84 billion/year by 2024 with products in the personal care, household, automotive, food, paints and medical sectors. Air pollution leads to an estimated 30-40,000 premature deaths each year in the UK, and aerosols transmit human and animal infections. More than 12 million people in the UK live with lung disease such as asthma, and the NHS spends ~£5 billion/year on respiratory therapies. Many of the technological, societal and health challenges central to these areas rely on core skills and knowledge of aerosol science. Despite this, an Industrial Workshop and online survey (held in preparation for this bid) highlighted the current doctoral skills gap in aerosol science in the UK. Participating industries reported that only 15% of their employees working with aerosol science at doctoral-level having received any formal training. A CDT in aerosol science, CAS, will fill this skills gap, impacting on all areas of science where core training in aerosol science is crucial.

Impact on the UK aerosol community: Aerosol scientists work across governmental policy, industrial research and innovation, and in academia. Despite the considerable overlap in training needs for researchers working in these diverse sectors, current doctoral training in aerosol science is fragmentary and ad hoc (e.g. the annual Fundamentals of Aerosol Science course delivered by the Aerosol Society). In addition, training occurs within the context of individual disciplines, reinforcing artificial subject boundaries. CAS will bring coherence to training in the core physical and engineering science of aerosols, catalysing new synergies in research, and providing a focal point for training a multidisciplinary community of researchers. Working with the Aerosol Society, we will establish a legacy by providing training resources for future researchers through an online training portal.

Impact on industry and public-sector partners: 45 organisations have indicated they will act as CAS partners with interests in respiratory therapies, public health, materials manufacturing, consumer and agricultural products, instrumentation, emissions and environment. Establishing CAS will deliver researchers with the necessary skills to ensure the UK establishes and sustains a scientific and technical lead in their sectors. Further, it will provide an ideal mechanism for delivering Continuing Professional Development for the existing workforce practitioners. The activity of CAS is aligned to the Industrial Strategy Challenge Fund (e.g. through developing new healthcare technologies and new materials) and the EPSRC Prosperity Outcomes of a productive, healthy (e.g. novel treatments for respiratory disease) and resilient (e.g. adaptations to climate change, air quality) nation, with both the skilled researchers and their science naturally translating to long-lasting impact. Additionally, rigorous training in responsible innovation and ethical standards will lead to aerosol researchers able to contribute to developing: regulatory standards for medicines; policy on air quality and climate geoengineering; and regulations on manufactured nano-materials.

Public engagement: CAS will provide a focal point for engaging the public on topics in aerosol science that affect our daily lives (consumer products, materials) through to our health (inhalation therapeutics, disease transmission and impacts of pollution) and the future of our planet (geoengineering). Supported by a rigorous doctoral level training in aerosol science, this next generation of researchers will be ideally positioned to lead debates on all of these societal and technological challenges.