Self Assembly of 3D Nano Structures

This is another advance in nanoengineering from a two dimensional surface acting as a substrate.  The possibilities become countless as do thepotentialities.

In the past several years we havewitnessed nano capabilities steadily advance one neat trick at a time.  I can think of little more exciting thesedays than attending a conference with all the players doing presentations.  Everyone must be trying to advance newmethods and the level of intellectual speculation must be huge.

It is interesting that they choseto use C60 or buckyballs for this trick.

Self Assembly of three dimensional structures from molecular buildingblocks

NOVEMBER 23, 2010

Scientists at The University of Nottingham have made amajor breakthrough that could help shape the future of nanotechnology, bydemonstrating for the first time that 3-D molecular structures can be built ona surface.

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

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

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 acidmolecules. The spherical shape of the buckyballs means they sit above thesurface of the molecule and encourage other molecules to form around them. Itoffers scientists a completely new and controlled way of building up additionallayers on the surface of the molecule.

STM images of different regions of a single layer TPTC network, allscale bars are 23A. (23 Angstroms, 2.3 nanometers)

Self-assembly of planar molecules on a surface can result in theformation of a wide variety of close-packed or porous structures.Two-dimensional porous arrays provide host sites for trapping guest species ofsuitable size. Here we show that a non-planar guest species (C60) can play amore complex role by promoting the growth of a second layer of host molecules(p-terphenyl-3,5,3″,5″-tetracarboxylic acid) above and parallel to the surfaceso that self-assembly is extended into the third dimension. The addition ofguest molecules and the formation of the second layer are co-dependent. Addinga planar guest (coronene) can displace the C60 and cause reversion to amonolayer arrangement. The system provides an example of a reversibletransformation between a planar and a non-planar supramolecular network, animportant step towards the controlled self-assembly of functional,three-dimensional, surface-based supramolecular architectures.

The research paper is the second significant breakthrough to bereported by the team in recent weeks. In September, a paper in NatureCommunications revealed they had demonstrated for the first time the way inwhich an irregularly shaped molecule is adsorbed on a surface. It represents astep towards being able to harness the potential of these molecules, which haveextremely useful properties, by organising them to form structures. They could offera way of building new data storage devices that are orders of magnitude smallerthan their existing silicon-based counterparts.

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