A new tool for understanding how organic surfaces get dirty
Professor Jeffrey Reimers
School of Mathematical and Physical Sciences
A combination of organic synthesis, scanning tunneling microscopy (STM) imaging and density functional theory calculations has led to new ways for understanding how organic surfaces get dirty. The work is the result of an international collaboration between Jeffrey Reimers and Mike Ford from UTS Science and researchers at Shanghai University (China), the University of Sydney, the University of Melbourne and Radboud University in The Netherlands.
Professor Reimers says their paper, recently published in the National Academy of Sciences of the United States of America (PNAS) (opens an external site), focused on organic molecules sticking to graphite.
“State of the art chemistry and materials modelling based purely on the quantum interactions between nuclei and electrons hasn’t been able to treat organic surfaces before, as the interactions that cause things to stick are diffuse and involve many weak interactions between many atoms,” Professor Reimers explained.
“Such fundamental methods historically have poorly represented these weak interactions, and the system size has been too large”.
Professor Reimers said the graphite surface (akin to graphene) is highly ordered making both experiment and computation much easier, allowing key properties of the interactions to be both measured and calculated.
“That our methods work for this simple testable situation implies they will also work for the other structurally more complex scenarios,” he said. “Many people already model these other scenarios, especially in the polymer and drug design fields, and a lot of success has been achieved. We can do better now.”
The team’s paper provides fundamental insight into the factors that control how and why the surfaces become dirty. It also demonstrates how to get critical information from traditional experiments, which Professor Reimers said can be applied to a large range of existing data.
“We have taken methods from the small-molecule arena and introduced them into the nanotechnology and biotechnology domains.
“There is still much to be done but related fields include the three dimensional structures of polymers, proteins and DNA all of which are held together by the same widely distributed weak forces.”
This research was undertaken with the assistance of resources from Australia’s national research computing service, the National Computational Infrastructure (NCI).