Polymer synthesis paves way for more energy efficient electronics

In a paper published in the Proceedings of the National Academy of Sciences, a group of researchers from US Dept of Energy's Oak Ridge National Laboratory (ORNL) and two Canadian universities outlined their success in growing highly structured short chains of polymer poly(3,4-ethylenedioxythiophene), or PEDOT. Analysis and understanding of the polymerisation process and results were provided with the help of ORNL supercomputers. According to ORNL scientists, Bobby Sumpter and Vincent Meunier, synthesising the PEDOT polymer could potentially have an impact on everyday electronic products. PEDOT is valued in electronic applications for the transparency, ductility and stability of its conducting, or 'doped', state. Because of its role as conductive material in OLEDs, PEDOT is found in many electronic devices such as televisions and computer monitors. To create ordered arrays of the PEDOT polymer, the team placed a precursor molecule onto a copper crystalline surface, which helped to guide and initiate the polymerisation reaction. Sumpter explained: "The chemistry and resulting stereochemical structure on the surface are very unusual. Most attempts to synthesise polymers usually result in imperfect polymer arrays with a very different prominent structure." By analysing the results through a 'virtual microscope,' based on density functional theory calculations and simulations performed on ORNL supercomputers, the highly organised structure of the polymer arrays, was revealed. Examining the polymer formation with the conventional means of scanning tunnelling microscopy combined with the virtual microscopy, enabled the team to illustrate the construction and bonding of PEDOT arrays. Meunier added: "This experiment defines what nanoscience is about - a mixture of experimental techniques combined with theoretical knowledge. It was an excellent opportunity to interface directly with experimentalists and establish new international collaborations."