Abstract
Nanoparticle characterisation has been and continues to be integral in the engineering of novel nanomaterials. Nanoparticle dispersions, in particular, have found myriad uses in industry, notably in some of the current Covid-19 vaccines. As nanoscale properties of nanomaterials have an immediate effect on their bulk scale applications, fast and robust nanoparticle characterisation in dispersions is required to keep up with the rapidly evolving nature of nanoscience. Nanoparticle Tracking Analysis (NTA), also called Particle Tracking Analysis and Brownian Motion Microscopy, has emerged as a excellent candidate for the determination of a key property of nanomaterials: size. Plenty of work has been done toward improving the technique and making it robust and repeatable. In fact, this technique has been adopted in a wide variety of laboratories to characterise nanoparticle dispersion systems, showing promise for the development and usefulness of this technique.Light has a variety of properties which, when leveraged appropriately, can produce interesting data on nanoparticle properties. This thesis aims to explore the use of certain properties of light, namely irradiance, wavelength, and polarisation state, in the effort to improve upon the data collection capabilities of NTA and push its applicability into new frontiers. Three key experiments corresponding to each of these properties were performed and show the ever-growing possibilities of NTA. In Chapter 1, the current state of nanoparticle dispersion characterisation is set out, and past work which has sought to improve and develop Nanoparticle Tracking Analysis is collated. The experimental portion of the thesis is contained in the following four chapters, where work toward the development of Nanoparticle Tracking Analysis is performed. In the first study, it is shown that laser power needs to be used with care so as to not reduce the precision and accuracy of the output size distribution. In the next study, wavelength-dependent scattering behaviour of nanoparticles is interrogated to allow for a remarkable improvement in the size distribution output from NTA. The last study utilises the polarisation change of scattered light due to nanoparticle shape to determine nanorod dimensions. Chapter 5 investigates the unexpectedly large uncertainties in depolarisation ratio output from the technique presented in Chapter 4. In Chapter 6, future experiments are suggested which were considered and have significant potential to push NTA further, but which time did not allow. This thesis concludes with an examination of how the experimental work performed here impacts the literature surrounding NTA. The research contained within these chapters demonstrates that NTA shows promise in extracting increasingly complex nanoparticle properties with increasing precision and accuracy via innovations in technique development.
| Date of Award | 21 Jun 2022 |
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| Original language | English |
| Awarding Institution |
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| Supervisor | Simon R Hall (Supervisor) & Henkjan Gersen (Supervisor) |