Feeling the heat

The speed at which heat moves between two materials touching each other is a potent indicator of how strongly they are bonded to each other, according to a study by researchers at the Rensselaer Polytechnic Institute.

To discover that fact, Prof Pawel Keblinski and Prof Shekhar Garde used extensive molecular dynamics simulations to measure the heat flow between a variety of solid surfaces and water.

They simulated a broad range of surface chemistries and showed that thermal conductance, or how fast heat is transferred between a liquid and a solid, is directly proportional to how strongly the liquid adheres to the solid.

'In the case of a mercury thermometer, thermal expansion correlates directly with temperature,' Keblinski said. 'What we have done, in a sense, is create a new thermometer to measure the interfacial bonding properties between liquids and solids.'

Garde added: 'We can use this new technique to characterise systems that are very difficult or impossible to characterise by other means.'

The discovery, which helps to better understand how water sticks to or flows past a surface, has implications for many different heat-transfer applications and processes, including boiling and condensation.

Of particular interest is how it might benefit new systems for cooling and displacing heat from computer chips - a critical issue currently facing the semiconductor industry, according to Garde.