‘The Sir Eric Rideal award lecture honours individuals who have made sustained and distinguished contribution to colloid and interface science. This year’s awardee is Joseph Keddie, professor of soft matter physics at the University of Surrey.’
Keddie is known for his pioneering work on polymer colloids, soft matter physics, sustainable materials and living materials, with an academic career spanning more than three decades. The lecture is awarded jointly by SCI and the Royal Society of Chemistry.
Can you tell me a bit about your research and its impact?
For most of my career I’ve studied one type of system: polymer colloids. Most people know what a polymer is – a constitute of plastic. A colloid consists of small (sub-µm) particles of one phase dispersed in another. A lot of my work is on polymer particles, maybe a few hundred nanometres in size, in water. We usually study synthetic latex synthesised by emulsion polymerisation, made from monomers being emulsified in water.
When making a coating, you start with a liquid and end up with a solid that has some use or function. It could be strictly decorative, but quite often it’s a barrier to prevent corrosion, such as the rusting of a surface.
One thing we’ve often asked in our research is how do the colloids go from one state to another? There’s a water evaporation process, the colloidal particles will pack together, and then they’ll fuse or coalesce into a continuous phase.
It sounds easy and simple, but there’s lots of subtlety. This multi-step process is called ‘film formation’, and much of my team’s work is studying it using many different methods.
Normally, what people get more excited about is what we can do with these polymer colloids. For instance, you can mix the particles with other things to make a composite. We’ve mixed them with carbon nanotubes and graphene, for instance.
My more recent work has diverged a little bit. In a collaboration with a microbiologist at the University of Surrey, Dr Suzie Hingley-Wilson, we’ve been essentially taking bacteria and putting them in a polymer colloid to create a ‘living paint’. (See the cover story in the C&I January 2026 issue.) When we add bacteria inside a coating, any function the bacteria can do, the coatings can also do.
One of our first examples was waste-water treatment, where the bacteria in coatings can convert ammonium into nitrites and nitrates, and then other bacteria will convert that into nitrogen gas. Another application is when we used cyanobacteria that can take up a carbon source and give off oxygen, so it’s an oxygenating paint.
More recently, we’ve been looking at taking up air pollutants, breaking them down and giving off less harmful gases. In ongoing research, microbiologists at Surrey have been genetically modifying E. coli so that it produces a greater amount of hydrogen as a biofuel.
What makes bio-coatings so interesting, and why is this important?
Part of why it’s interesting is because it’s challenging to me personally: it’s a new direction and I think it does capture the imagination a little bit.
Bacteria have evolved over millennia; they’re one of the oldest organisms on Earth and they’ve really been optimised by Nature. Some species are quite efficient in chemical reactions or can withstand harsh environments. Bacteria are very good at things like chemical synthesis, so why not use them directly rather than trying to re-create what they do?
How has the field evolved since you’ve been working in it?
I think the field of polymer colloids has evolved somewhat: when I first started (in the 1990s) it was mainly adhesive and paint companies who were interested, because they wanted to remove Volatile Organic Compounds (VOCs) from their products. They were developing new water-based formulations. Early in this century, researchers in nanomaterials realised that polymer colloids could be really useful when combined with carbon nanotubes and graphene to create functional properties. The recent trend in moving polymer colloids into biology is definitely an evolution in the field.
Are there still discoveries to be made?
I think there are still some discoveries on the control of microstructures of the living paints (or biocoatings) and maybe other things we can do. It’s all about increasing the viability and the reactivity of the bacteria and keeping them alive for longer. There are certainly more discoveries in that direction to be made.
The other direction in biocoatings is in new applications. There are all sorts of bacteria out there that offer a range of useful functions, almost like microscopic engines or tiny reactors. There are extremophiles that can survive in extreme environments, such as high salt concentrations, in acids, or under radiation. On the chemistry side, biocoatings can be linked to green synthesis: rather than having huge reactors in factories making certain chemicals, maybe we can just use bacteria confined to coatings to make them.
How important is industry collaboration to you?
Historically, in my career, collaboration with industry has been absolutely essential. I learned a lot from industrialists, as they have knowledge that is not widely known in academia, and they quite often can pose interesting questions that I hadn’t thought of. More recently, I have been applying my knowledge of coatings as a Royal Society Industry Fellow, working with a sustainable materials company (Pulpex – see C&I, April 2025).
What impact does the award have?
It’s highly gratifying! The Rideal award is special because the nominations come from the colloids community. I think the award is also a chance for me to stop and reflect about what I’ve done over the last 30 years.
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