Advanced microscopy tests 60-year-old mechanism of ethylene polymerisation

For the first time, researchers have visualised the step-by-step formation of polyethylene from simple monomers. They achieved this thanks to scanning tunnelling microscopy (STM), which provides atomic resolution to follow the fate of propagating polymer chains on the catalyst surface. The experiments confirm a classic reaction mechanism proposed almost 60 years ago.

The discovery was serendipitous, explains lead author Kai Wu from Peking University, China. ‘We tried iron carbide because it had worked for similar reactions […] luckily it also catalysed ethylene polymerisation,’ he says. This very active solid surface was key to visualise the reaction, together with advanced STM techniques.