Milk, ink or paint: you do not want these substances to form lumps. But why does this happen occasionally? And how can you prevent this? That's broadly speaking the topic of my research. I investigate colloids: small particles which you can find in many substances, for example in milk, mist and mud, but also in clay, paint and even in our human body.
Colloids influence the properties of all kinds of products
Colloids are spontaneously moving particles, less than one-thousandth of a millimetre. We can not see them with the naked eye, but they do influence the properties of all kinds of products. Without colloids there would be no good mayonnaise, wet look gel or photocopy, as colloids influence the “smoothness” of a product. There is a strong overlap between the colloid science and nanotechnology. Nanoparticles are actually another factor of a thousand smaller than colloids.
We focus on the fundamental understanding of these colloid particles. We study how to make them and how they can achieve a good stability. By stability I mean how you can ensure that these particles keep moving without clotting together. Consider paint for example. You don’t want the pigment particles in paint to stick together, because they will sink straight to the bottom. As a result the paint might become useless. But how can you prevent the particles from sticking together? One solution is to coat the pigment particles with a polymer layer - a kind of plastic film.
In our lab we create various model systems, so we do not actually study paint or milk. By using model systems, we can properly monitor and control the characteristics of colloidal particles. Paint and milk are actually very complex substances. We create a relatively simple model, which provides better understanding of practical substances like paint or milk.
Another important system, which we investigate, is composed of magnetic colloids. Imagine you have blood or urine and you want to extract certain proteins. You could add magnetic particles, which specifically bind these proteins. Next the colloids are collected with a magnet, so the colloids serve here as a separation tool. This tool is commonly used in biomedical research for diagnostic purposes. It can also serve to identify the presence of drugs or other substances in urine or blood.
Another achievement of colloid science was to explain the silting up of harbours. If you're in the garden and take a scoop of clay, there are a lot of colloid clay particles in it. These particles carry an electrical charge, so they will repel each other. However, if these particles come into contact with salt water, this repulsion disappears.
As a result, the clay particles will stick to each other. This is the case for example if fresh river clay particles flow into a salty sea, such as the North Sea. The clay particles suddenly experience a large salt system, will stick together and will sink to the bottom. Therefore, many harbours suffer from silting. It is important that you know the cause of such a phenomenon
I am Albert Philipse, head of the Van 't Hoff laboratory for Physical and Colloid Chemistry at Utrecht University. I investigate colloids. These are spontaneously moving particles, which we can not see with our naked eye, but nevertheless they strongly influence all kind of products. From milk and mud, to paint and even our human body. With my expertise I might be able to help you to improve for example food and paint. My dream? A collaboration between medicine and colloid science: that could contribute to understanding and preventing diseases.
Colloid science is very useful for the food industry. For example, no one knew exactly how cheese is being made. Of course: you've got milk, you add a certain enzyme, aggregation appears and suddenly you have cheese. But how does this work exactly? And how can you optimize this process? Insights from our laboratory provide a deeper understanding of such processes and ways to improve them.
What I would really like to see for the future is more collaboration between medical science, biology and colloid science. Human cells contain many colloids; therefore medicine might learn a lot from colloid science. In turn, medicine could inspire colloid science with urgent and interesting problems to work on. This collaboration is still in its infancy. Nevertheless, colloid scientists are investigating how some viruses are formed and how they function. But there are so many more biological topics to work on. All this research could contribute to understanding and preventing diseases. That would be wonderful. Currently there are no programs to finance this kind of crossover research. Government or industry should take the initiative to support this sort of cooperation.
Colloid science, colloids, nanomaterial’s, nanotechnology, ferro-fluids, magnetic colloids, magnetic fluids, medical diagnostics, biosensors, water purification, colloid chemistry, colloidal systems, colloid fluids, improving food, cheese, milk, paint, drug discovery, non-spherical colloids, rods, fibers, colloid dynamics