Group Members: James Day

Photo of James Day


Bain Group History

Part II Undergraduate Student, University of Oxford, 2003–2004
D.Phil. Student, University of Oxford, 2004–2005
Ph.D. Student, Durham University, 2005–present

Project Title

Understanding the Properties and Stability of Food Emulsions

Research – Outline

The aim of my research is to study the underlying chemical behaviour and properties of the oil–water interface under the influence of dairy proteins and emulsifiers. Although the macroscopic properties of these emulsions have been well-characterised, our knowledge of the molecular properties has mostly been derived by inference from TENSIOMETRY experiments and so I intend to use and develop ELLIPSOMETRY and evanescent wave RAMAN SPECTROSCOPY to investigate this ubiquitous interface.

Research – A Closer Look

Understanding the properties of the oil–water interface is crucial to the design and development of food emulsions, such as ice-cream, spreads and sauces. Surface-active milk proteins, including ß-casein and ß-lactoglobulin, and small organic surfactants, such as lecithins and tweens, are typically used to stabilise these emulsions, although the use of non-dairy proteins such as soy, lupin and pea has become more widespread in recent years for economic and health reasons. A more detailed understanding of the underlying chemical behaviour of dairy protein emulsions will enable us to relate these properties to the alternative non-dairy proteins.

The oil–water interface is a buried surface and hence the application of laser-based experimental probes poses a number of technical challenges. To investigate this surface using ellipsometry, I use light guides and a specially-designed cell to introduce the laser beam and to generate a planar interface. Both of these techniques are based on work done by the Nylander group in Sweden. Ellipsometry is extremely sensitive to thin films at an interface and has good kinetic resolution. These properties should enable me to study variations in protein film thickness with time in the absence and presence of competing surfactant. However, ellipsometry only gives limited structural information and I intend to develop evanescent wave Raman spectroscopy at the oil–water interface to investigate the structure of emulsifier and protein films.

Project Funding

This project is sponsored by the BBSRC in conjunction with an industrial CASE award from Unilever (Colworth).


J. P. R. Day, C. D. Bain "Ellipsometric Study of Depletion at Oil–Water Interfaces" Phys. Rev. E 2007, 76, 041601 (DOI).

J. P. R. Day, R. A. Campbell, O. P. Russell, C. D. Bain "Adsorption Kinetics in Binary Surfactant Mixtures Studied with External Reflection FTIR Spectroscopy" Journal of Physical Chemistry C 2007, 111, 8757-8774 (DOI).

R. A. Campbell, J. P. R. Day and C. D. Bain "External Reflection Fourier Transform Infrared Spectroscopy of Surfactants at the Air–Water Interface: Separation of Bulk and Adsorbed Surfactant Signals" Applied Spectroscopy 2005, 59, 993–1001 (DOI).

M. Sekine, R. A. Campbell, D. S. Valkovska, J. P. R. Day, T. D. Curwen, L. J. Martin, S. A. Holt, J. Eastoe and C. D. Bain "Adsorption Kinetics of Ammonium Perfluorononanoate at the Air–Water Interface" Physical Chemistry Chemical Physics 2004, 6, 5061–5065 (DOI).

R. A. Campbell, S. R. W. Parker, J. P. R. Day and C. D. Bain "External Reflection FTIR Spectroscopy of the Cationic Surfactant Hexadecyltrimethylammonium Bromide (CTAB) on an Overflowing Cylinder" Langmuir 2004, 20, 8740–8753 (DOI).

Note: you can check out other publications by Colin Bain SORTED BY YEAR or SORTED BY TOPIC.


I am interested in watersports in general and windsurfing in particular – whilst at Oxford I was heavily involved in the windsurfing club and have spent numerous summers teaching windsurfing and sailing in the Mediterranean. I also enjoy swimming and walking.