SPUR Project

2008 Winner (10 of 15)

Surface Profilometer Study of Evaporating Polymer Solutions
Supervisor: Dr David Fairhurst (Physics and Maths)

This project investigated a recently published phenomenon (Allain and Pauchard, Europhysics News (2005) Vol 36, no. 1) that has also been studied by NTU PhD student, David Willmer. The 2-dimensional profile of drying droplets placed on thin glass slides have been recorded using high quality video equipment. Typically, the height of a water droplet steadily decreases due to evaporation. However, intriguing behaviour occurs with complex liquids: for example, the height of an aqueous polymer solution (polyethylene glycol) initially decreases, before rapidly increasing and finally decreasing again. In addition, dextrose solutions have been seen to bend and even break the glass slide. The student studied this process using a variety of polymer solutions at different concentrations and in doing so contributed to the active research field of non-equilibrium complex fluids. Understanding the behaviour of complex fluids has applications in various industries, including paint, ink-jet printing, oil extraction, cosmetics and microfluidics.