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From theory to application: the Bristol Colloid Centre

15 March 2003

What are colloids? An everyday experience, says Dr Paul Reynolds, manager of the Bristol Colloid Centre.

Have you every wondered why milk curdles, how your soluble aspirin dissolves, or why cement sets so hard? Maybe you are concerned about the environment and wondered why new aerosol sprays are better than the ones that ruined the ozone layer, or how we can make sure that our sewage and waste are effectively disposed of? It might not be obvious, but there's a common theme running through all of these areas - the link is 'colloid science'.

So what is colloid science? Well, colloidal materials are an everyday experience. Any product that consists of one material existing as particles or droplets within another relies on colloid science for its success. But these particles are extremely small - if one was the size of a football, the football would be the size of the Earth. The particles in a true colloid are so small that they remain in suspension indefinitely, unaffected by gravity.

Examples of colloidal systems include:

  • milk - liquid fat droplets emulsified in water
  • paints - small pigment particles dispersed in a carrier fluid
  • aerosols - liquid droplets dispersed in air
  • blood - the cells that flow through our veins are colloidal particles

It is hard to think of a manufacturing process that does not involve a dispersed state at some stage. So, given its industrial relevance, colloid science is an area where purely academic research has always run hand in hand with its application to industry.

The University's Department of Chemistry has a long history of working with industry: 125 years ago, experiments putting dyes onto wool were performed in order to support the needs of local industry. Wool and dyes are historically important to Bristol and both have played an important part in Bristol's industrial heritage. Indeed, 'Bristol Red', seen during graduation ceremonies, was originally made from a local dye product. This tradition of academic research being translated into industrial opportunity has been carried on into the present century in an unbroken period of research at Bristol University's Chemistry Department. Eventually, to meet the ever-increasing demands of industry, the Bristol Colloid Centre (BCC) was set up to transfer fundamental colloid science into a commercially viable technology. As a consequence, BCC now works with a wide variety of industries and technologies ranging from biomedicine and agrochemicals to printing inks and oil recovery.

But these particles are extremely small - if one was the size of a football, the football would be the size of the Earth

In the space of ten years, the BCC has developed from a small group to an integrated, multi-dimensional organisation with a turnover of £1 million a year. It has been so successful that it is now recognised as a centre of excellence by the government, the research councils and the Royal Society of Chemistry. Indeed, the BCC is acknowledged world-wide for its ability to service the needs of industry to industry standards. The work has involved over 500 companies in all sectors of industrial manufacturing, of which about half have been small- to medium-sized enterprises (SMEs) which traditionally have not accessed university research opportunities.

But what exactly does the BCC do? Well, take for example the local businessman who came to the BCC with an idea for an environmentally friendly paint stripper. What was needed was a water-based product. Given this condition, the product had to stay in place for more than 12 hours to be effective. A bit of a problem if it was painted on vertical surfaces and was as runny as water! However, the BCC was able to formulate a product that allowed the stripper to be painted on easily and then to form a gel that would keep the product on the surface. It worked. Home Strip is now a commercial success and won a millennium award for technology. While the businessman knew the requirements that were needed, it was the experience of the BCC that enabled the product to come to fruition.

A more recent project involves the additives in engine oils. The oil used in car engines is a miracle of technology. It cleans the engine from the inside, mopping up the acidic by-products of the combustion process, helping to keep carbon-based impurities from clogging up the inside of the engine. It is the colloidal additives that improve the oil's cleaning performance. The BCC has recently built a collaboration between two companies and the University of Hull to help develop the next generation of oil additives.

In the space of ten years, the BCC has developed from a small group to an integrated, multi-dimensional organisation with a turnover of £1 million a year

Other successes of the BCC include making insoluble pharmaceuticals such as asprin disperse easily in water; sprayable herbicides; consolidated clay suspensions in huge tanks for easier waste disposal; cements that are easier to work with; improved skin sunscreen; high-temperature inks for novel printers; mud for coating oil well walls so the oil does not penetrate into the rock; and formulating materials for surgical implants. This varied and interesting range of problems provides a real challenge to the scientists who work in the centre, many of who have gained a PhD from Bristol and have a variety of industrial experience.

But the BCC does not rest on its laurels. The government has been saying for years that British industry needs to take advantage of the world-class research that is undertaken in its universities. The latest model for making this work is The Faraday Partnership scheme, which brings researchers and businesses together. The BCC was instrumental in setting up IMPACT, a Faraday Partnership in colloid technology. An example project is the ACORN programme in nano-technology, reported in re:search (July 2002). This programme, which aims to transfer the latest nanoparticle technology research into the UK microelectronics, high performance materials and pharmaceutical industries, is worth £4.2 million, with much of the research money coming to Bristol. In addition, in April this year IMPACT will roll out its first training courses to be delivered completely over the internet, putting IMPACT and the BCC at the forefront of training provision for industry.

The challenge for the BCC over the coming years is to embrace nanotechnology, an area of fantastic potential which is inextricably linked to colloid science. The principles are the same since both disciplines are concerned with systems where surface effects will dominate over bulk effects. The technology is in its infancy but once mature we shall be able to build things from the atom up and rearrange matter with atomic precision. The Bristol Colloid Centre is ready and waiting.

Dr Paul Reynolds / The Bristol Colloid Centre

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