Mathematical Modelling and Analysis of Industrially-Important Flows of Liquid Crystals: Spreading and Channel Filling

Lead Research Organisation: University of Strathclyde
Department Name: Mathematics and Statistics


Summary: This project is supported by an Engineering and Physical Sciences Research Council (EPSRC) Industrial CASE PhD studentship in conjunction with Merck Chemicals Ltd (Merck). The project will be supported by the Smith Institute for Industrial Mathematics and System Engineering.

Project Background: Liquid crystal displays are now ubiquitous as displays in modern electronic devices, such as flat large-screen televisions, laptops, mobile phones, digital cameras and electronic toys. However, as the number and scale of display technology applications continue to grow the technical demands grow alongside them, and with 40 years of experience in the field of liquid crystals Merck are at the cutting edge of developing new and more efficient displays and the techniques for manufacturing them more cheaply and efficiently (sometimes called "process intensification"). Liquid crystal display manufacturing is a multi-billion pound international industry, and so even relatively small scientific and technological improvements can have substantial economic benefits both to the companies involved (in terms of increased profits) and to wider society (in terms of more widespread access to more affordable and more reliable devices).

Strathclyde Context: The University of Strathclyde in Glasgow has a well-established track record in the theoretical analysis of liquid crystals, dating back to the pioneering work by Professor Frank Leslie FRS who, together with Professor Jerry Ericksen, formulated the famous and widely-studied Ericksen-Leslie equations for nematic liquid crystals. The Continuum Mechanics and Industrial Mathematics (CMIM) research group at Strathclyde (led by Professor Wilson) has particular expertise in studying the flow of complex fluids (and, in particular, liquid crystals) and a wide variety of thin-film flows.

Project Aims: The aim of the proposed project is to use a combination of analytical and numerical techniques to bring new insight and understanding to fundamental scientific problems associated with the manufacturing of liquid crystal display technologies, specifically the spreading of a liquid crystal over a physically and/or chemically heterogeneous substrate, and the filling of a narrow channel with a liquid crystal.

Supervision: The project will be supervised by Professors Stephen Wilson and Nigel Mottram in the Department of Mathematics and Statistics at the University of Strathclyde and Dr David Wilkes (Merck Germany) and Dr Rachel Tuffin (Merck UK). The student will be based at Strathclyde, with regular visits to Merck in Southampton and Germany.


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Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/P51066X/1 01/10/2016 30/09/2021
1795982 Studentship EP/P51066X/1 01/10/2016 31/12/2020 Joseph Cousins
Description This project aims to model industrially important flows of liquid crystal. Guided by collaborators at Merck KGaA we have modelled various aspects of liquid crystal device manufacture. This models have included; a model for the coalescence of liquid crystal droplets, a model for the squeeze flow of a droplet of liquid crystal and a model for the behaviour of liquid crystal near surfaces during squeezing.

Our key findings are that liquid crystal device manufacture is often done in a regime with very high flow speeds where damage to delicate parts of the device can be damaged. We have shown excellent qualitative results linking the flow speeds present in manufacturing to a common device defect known as the one-drop-filling mura.

More recently we have looked at a static thin ridge of liquid crystal with the aim of bringing further understanding to the interaction of surface tension, surface anchoring and elasticity in depositions of liquid crystal.
Exploitation Route Our findings provide liquid crystal manufacturers with evidence that defects caused during device manufacture could be caused by high flow speeds. Furthermore, these findings also show key ways to reduce the these high flow speeds and potentially reduce the occurrence of defects produced in manufacturing.

Understanding the role that surface anchoring treatment may play on the free surface and director structure in thin depositions of liquid crystal.
Sectors Chemicals,Electronics,Manufacturing, including Industrial Biotechology

Description A model for the coalescence of droplets during a popular liquid crystal device manufacturing method has been utilised by Merck KGaA.
First Year Of Impact 2018
Sector Electronics,Manufacturing, including Industrial Biotechology
Impact Types Economic