Determining the timescale of self-assembly of lyotropic phases in aerosols

Theme: Basic processes

Start date: Cohort 2: 2020

Supervisors: Dr Adam Squires, Prof. Jonathan Reid


We will design and develop a machine to obtain information about the timescales and processes behind the self-assembly of phases in aerosols. Once built, experiments will progress through increasing levels of complexity, starting with basic verification of the correct functionality of the apparatus through to detailed analysis of atmospherically, industrially, or pharmaceutically relevant applications making use of evolving, environment-dependent, aerosol phases. 

Aerosols are present in all walks of life and often contain molecules which are capable of forming complex phases through processes known as self-assembly. As solvents are taken up and released by the system, the molecules can adopt different shapes and conformations, known as lyotropic phases. The variation of these phases is a widely researched topic with various applications such as the development of smart materials. Similarly, aerosol science is a rapidly developing area of research, not only in the context of the current SARS-CoV-2 epidemic but also in fields such as industrial spray drying, atmospheric processes and inhaled drug delivery. However, rarely are these two domains considered simultaneously; the self-assembly of complex phases in aerosols is often overlooked, which is an unfortunate oversight caused by a lack of interdisciplinary communication. 

This project aims to link these two fields by developing a platform to study the self-assembly of amphiphiles in aerosols, both at equilibrium and during the formation of the phases. This platform will consist of a piezo-electric droplet-on-demand generator which will produce a droplet containing molecules which are known to self-assemble. This droplet will then go on to be trapped in an electrodynamic balance where the relative humidity in the levitation chamber will be controlled in real time. Small angle X-ray scattering data will be collected on the droplets as a function of suspension time and of relative humidity.  

Using the time-resolved scattering data, we will be able to elucidate the timescales over which self-assembly occurs in aerosols. In turn the timescales and changing structure as the system moves towards equilibrium will allow us to draw conclusions as to the processes by which they form. Understanding these processes and the timescale on which they act is key to determining the potential impact of these systems. For example, we will know which phase is deposited in the lung for an inhaled drug, or the morphology produced when spray drying a certain solution, provided we know the time allowed for equilibration and the conditions of the environment. This will improve the effectiveness of medical interventions and the reliability of industrial processes.