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Molecular building blocks form three-dimensional structures on surfaces

Brian Wang at Nextbigfuture sends this news of “Self assembly of three dimensional structures using molecular building blocks by the University of Nottingham. The new process involved introducing a guest molecule — in this case a ‘buckyball’ or C60 — on to a surface patterned by an array of tetracarboxylic acid molecules.” Further details are provided by a University of Nottingham press release “World first to provide building blocks for new nano devices“:

Scientists at The University of Nottingham have made a major breakthrough that could help shape the future of nanotechnology, by demonstrating for the first time that 3-D molecular structures can be built on a surface.

The discovery could prove a significant step forward towards the development of new nano devices such as cutting-edge optical and electronic technologies and even molecular computers.

In a paper published in the prestigious journal Nature Chemistry, the team of chemists and physicists at Nottingham have shown that by introducing a ‘guest’ molecule they can build molecules upwards from a surface rather than just 2-D formations previously achieved.

A natural biological process known as ‘self-assembly’ meant that once the scientists introduced other molecules on to a surface their host then spontaneously arranged them into a rational 3-D structure.

Professor Neil Champness said: “It is the molecular equivalent of throwing a pile of bricks up into the air and then as they come down again they spontaneously build a house.

“Until now this has only been achievable in 2-D, so to continue the analogy the molecular ‘bricks’ would only form a path or a patio but our breakthrough now means that we can start to build in the third dimension. It’s a significant step forward to nanotechnology.”

Previously, scientists have employed a technique found in nature of using hydrogen bonds to hold DNA together to build two-dimensional molecular structure.

The new process involved introducing a guest molecule — in this case a ‘buckyball’ or C60 — on to a surface patterned by an array of tetracarboxylic acid molecules. The spherical shape of the buckyballs means they sit above the surface of the molecule and encourage other molecules to form around them. It offers scientists a completely new and controlled way of building up additional layers on the surface of the molecule.

The abstract of the Nature Chemistry paper notes that if the non-planar guest species (C60) is replaced by the planar guest coronene (six benzene molecules fused into a circle) then the 3-dimensional arrangement of two parallel layers reverts to a monolayer, allowing the authors to conclude:

The system provides an example of a reversible transformation between a planar and a non-planar supramolecular network, an important step towards the controlled self-assembly of functional, three-dimensional, surface-based supramolecular architectures.

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