Newcastle University X-ray service looking a winner on the surface

JOHN HILL talks to a university professor involved with a new and specialised national X-ray service.

Professor Peter Cumpson with Newcastle University nanoLab's new X-ray Photoelectron Spectroscopy
Professor Peter Cumpson with Newcastle University nanoLab's new X-ray Photoelectron Spectroscopy

JOHN HILL talks to a university professor involved with a new and specialised national X-ray service.

THERE are times when Professor Peter Cumpson probably feels like the kid with his hand up at the back of the room, desperate to answer a question that has the rest of the class stumped.

“It can be very frustrating for people in our field,” he says.

“If an industry that’s facing a problem where two components that are glued together start falling apart, it often tries lots of different formulations to try to work out what’s happening.

“I often think that if they’d scraped off some of the material and come to me six months earlier, I could have done a quick analysis and probably told them what was going on.”

Prof Cumpson is part of Newcastle University’s team at the School of Mechanical and Systems Engineering.

He’s also set to oversee a new service that will see all sorts of state-of-the-art materials wing their way up to the North East.

Newcastle University has been selected as the UK provider of the Engineering and Physical Sciences Research Council’s National X-ray Photoelectron Spectroscopy (XPS) service, which will be located in the university’s nanoLAB.

The new centre will be opened today by Dave Delpy, the chief executive of the EPSRC, and is part-funded by outgoing regional development agency One North East.

Cumpson himself is excited about the potential for XPS, which has been in use for several decades but is only just bedding in to a number of new sectors.

“My enthusiasm for this is well-justified,” he says.

“There are so many academic and industrial areas that could benefit. Rather than spend half a year working on what may be going on, they can use this to say exactly what’s happening.”

But what exactly does XPS do, and why would this be of interest to people as diverse as UK academics, dishwashing liquid makers, healthcare providers and hard-drive manufacturers?

Basically, XPS is an unambiguous way of finding out exactly what’s on the surface of a material.

While what’s on the inside of a material is important, what’s right on the top will influence how it reacts with other materials, and that has repercussions in all sorts of areas.

Cumpson says: “Say you’re in the aerospace industry, and you’re joining pieces of aluminium together to make a wing, that could fail if you’ve got a single layer of oily material on the surface.

“You have to clean the surface efficiently, and XPS is a really good way of finding out if you’ve got something on the surface which could interfere with the cleaning.

“In other cases, you might need a very thin film of oil to ensure lubrication.

“The pick-up heads on a hard disk drive are flying on a thin layer of air microns over the surface, and gliding over it. You need some lubricant there, but it needs to be vanishingly thin to ensure performance, and that’s where XPS can come in.”

XPS enables experts to identify and analyse the composition of the surface layer at an atomic level.

The process involves cleaning the surface and then putting it in a very high vacuum, which slows down the rate at which molecules hit the surface to such an extent that collisions will not occur during the experiment itself.

Then the surface is hit with a beam of X-rays, which cause the ejection of electrons from the surface.

An analysis is then made of the electrons themselves.

Each element has its own distinctive energy reading, and by measuring the reading registered by every electron that escapes, it can be determined with certainty what type of element is on that surface.

The technology on offer also allows researchers to gradually erode surface layers by throwing ions at them, giving them a profile of individual layers of the material.

“The great thing about XPS is that it’s unambiguous, and it can give you analysis of what the surface actually is, as well as its thickness,” says Cumpson.

“People have made use of surface analysis in the past, including International Paint in Gateshead.

“It makes a lot of marine paints, and if you’re painting something you know what ends up on the surface can be entirely different to what’s in the bulk of it.

“If something is right on the surface, it changes the way the paint interacts with the environment.

“One of the things that made ICI a lot of money back in the day was the surface treatment you apply to plastics so you could print on them.

“Printing ink may be water-based and plastic is organic material, so if you try to print on it, the ink balls up. But they did special plasma treatment of the surface and that made it work.”

The project benefits from an ICI link, as it will also be run from a second site at the former ICI lab in Wilton by former ICI man Prof Ian Fletcher.

Fletcher’s experience with XPS includes a spell as part of Prof David Brigg’s ICI group which purchased the first ESCA300 spectrometer in 1988.

Cumpson also worked with XPS in as part of his 20-year spell at the National Physical Laboratory, and says the new Newcastle University facility will allow the region to push itself back to the front line of the research.

He says: “ICI in Wilton developed uses of XPS and applied them, and a lot of initial research was done at Durham University.

"By the 80s, there was a lot of work being done at Newcastle University. So this area has a very strong history with this.

“Twenty to 25 years ago we were at the cutting edge of instrumentation and this will give us instrumentation at the top end again.

“By the middle of next year we’ll have one of the most comprehensive XPS facilities in the UK.”

The process is already interesting companies in the pharmaceutical industry, who may want to check the properties of the outside of a pill that is designed to dissolve in the stomach after a certain time.

It’s also of use to companies who make dishwashing liquid, who are interested in ways to remove dirt on the surface of dishes with more efficiency or less water.

It could also be applied to solar cells, fuel cells, mobile phones and interactive computer games, and Cumpson is actively seeking companies that may be able to apply this process to their work.

He’s particularly interested in the potential of biological sectors, such as healthcare.

He says: “If you ever end up in hospital, there’s a chance they’ll stick a catheter in you at some point.

“The first reaction of the body is to deposit random proteins in the blood which will absorb into the surface of the catheter and form cells on that surface.

"In unpleasant cases bacterial infections will build up on the surface. We need to formulate the surface of these catheters to stop this happening.

“XPS could help engineer surfaces that could either discourage the depositing of cells or promote them, in the case of tooth implants, in which you want to get adhesion to the bone.

“As diagnostic tools they’re really powerful, and it could be of great benefit to the NHS in areas such as making sure the body’s reaction to replacement hip joints is better. The medical area is a real area of growth.”

While it will be a national facility for research, continuing the incremental progress that has taken place since the 1960s, it will also be available as a regional facility which can be accessed by local industry.

EPSRC’s Prof Dave Delpy says: “EPSRC’s new suite of mid-range facilities underpin the outstanding research being done across the UK in the engineering and physical sciences whilst providing an excellent level of service.

“XPS has a wide range of applications and the EPSRC National Centre at Newcastle has an exciting vision for the future of this cutting- edge technology and how to ensure the delivery of state-of-the-art XPS capabilities for UK users.

“The facility is working with existing users of XPS as well as bringing in new users from across a variety of scientific disciplines to expand the use of this technique to address a multitude of important scientific questions.”

 
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