Prime Minister's Prize for Science - Boger Fluid(06/10/2005)
Just days after the announcement, Catalyst will profile this yearís recipient of the Prime Ministerís Prize for Science.
Karina Kelly, reporter: Itís one of lifeís great problems Ė getting the tomato sauce out of the bottle. So we end up whacking it out and Ė scientifically speaking Ė that changes it from a solid into a liquid.
Narration: Tomato sauce is one of whatís called non-Newtonian fluids and getting them to flow is also a problem facing many industries.
Up until the late 80ís Alcoaís alumina refineries had to water down 20,000 tonnes of sauce-like toxic slurry every day, just to get it through the pipes Ė but that was causing even more waste to dispose of.
Enter Professor David Boger. Heíd been playing with fluids since the 1970ís, when chemists believed that they were all simply either Newtonian or non-Newtonian Ė like the tomato sauce.
Professor David Boger: Ok, a Newtonian fluid is a simple fluid like this water here Ė it has a constant viscosity no matter what you do to it, like pouring.
But a non-Newtonian fluid does change its viscosity depending on what you do to it...
Take this old childhood favourite, Silly Putty. When you deform it slowly Ė like youíre doing - youíve got big molecules in there that have time to align with the flow and so they slide by one another and the result is stretching. (Now roll it up and do the same thing fast). So now when you deform it very rapidly, the molecules donít have the time to flow and the putty breaks instead. It behaves like a solid.
Narration: But could there be another class of fluids?
It was back in 1975 that David was experimenting with adding polymers to fluids, when he happened upon an extraordinary result.
Professor David Boger: We were working on fluid like materials, And it became very clear that there was a missing link in terms of - there were constant viscosity fluids but there were no constant viscosity elastic liquids. And we naively believed we could build one of these things. And that naivety was based in ignorance and it turns out we did. We were able to do that by adding parts of a big molecule to a very viscose material.
And low and behold these materials did have a constant viscosity and were very elastic.
Narration: David had discovered a new class of non-Newtonian fluids that was so significant, they named them after him.
Like most non-Newtonian fluids, Boger fluids are elastic but they differ in that they have a constant viscosity, meaning that you can predict and control what they do. And what they can do is pretty amazing.
Karina Kelly, reporter: So David this one is a normal fluid and itís got that little vortex in the middle of the mixer, what have you got over here?
Professor David Boger: Well over here we have a material that has the same viscosity Ö and as youíll see, this material will climb up the rod. Both have the same viscosity, but this one is elastic. So itís a constant viscosity elastic liquid.
Narration: And it just gets stranger...
Professor David Boger: In this type of material, it responds depending on what you do to it. If you lift it very slowly it will think itís a liquid ... And if you lift it really quickly it will behave like a solid.
Narration: Wow, itís as if itís become heavier! Thatís amazing.
Professor David Boger: And if you stretch it, it will think itís a solid too, if you pull it apart.
Karina Kelly, reporter: You get paid to do this stuff?
Professor David Boger: Yes, itís been a good career and weíve had a lot of fun for a long period of time.
Narration: Itís the serious work though thatís allowed many industries to solve countless sticky problems.
In the case of Alcoa, it was creating new ways of getting thick sludge through pipes without having to water it down.
It allowed the old lake-waste storage system to be replaced with a dry stacking method which halves the amount of land used and forms a firm, stable surface that can eventually be regenerated with vegetation.
The latest in fluid mechanics though, is moving from large-scale flow to small - microfluidics. Justin Cooper-White is one of its leading researchers.
Justin Cooper-White: One example is when youíre impacting water on to leaf surfaces for agricultural chemical dispersion. It will retrack because of its high energy and leave the surface. And thatís a big problem, because if youíre spraying you donít want to lose all the good chemicals and you certainly donít want to go on to the other crop.
So by the addition of a small amount of polymer weíre actually able to allow it to hit the surface, spread and stick.
So this allows us with huge applications in agricultural chemicals, new nozzle designs for inkjet printing Ė a multitude of applications.
Narration: So after nearly 30 years of pouring, mixing, squeezing and stretching, Boger fluids are continuing to give us a greater understanding of how all fluids behave.
Itís a journey thatís being recognised with this yearís Prime Ministers Prize for Science Ė making a total of 14 international awards for David.
Karina Kelly, reporter: But David are you going to do something about that big problem Ė making tomato sauce come out of the bottle easier?
Professor David Boger: Karina, thatís solved.
- Reporter: Karina Kelly
- Producer: Gabrielle Betteridge
- Researcher: Gabrielle Betteridge
- Camera: yes
Laureate Professor David Boger
University of Melbourne
Associate Professor Justin Cooper-White
University of Queensland
Comments for this story are closed. No new comments can be added.
25 Oct 2009 6:09:04am-
I am not sure how is this any relevant to biomedical problems?
it will be great if you can give me some clue on how is the boger fluid related?