Can self-assembly based technologies offer advantages beyond conventional top-down lithography approaches?
To ensure the survival of Moore’s law and the success of the nanoelectronics
industry, alternative patterning techniques that offer advantages beyond
conventional top-down patterning are aggressively being explored.
A joint effort of the Aalto University of Helsinki, the Politecnico di Milano,
and VTT Technical Research Centre of Finland has now demonstrated that it is
possible to align molecular self-assemblies from nanometers to millimeters
without the intervention of external stimuli.
Molecular self-assembly is a concept derived from Nature that leads to the
spontaneous organization of molecules into more complex and functional
supramolecular structures. The recipe is “encoded” in the chemical structure
of the self-assembling molecules. Molecular self-assembly has been exploited
for “templating” functional devices, molecular wires, memory elements, etc.
However, it has typically required additional processing steps to achieve
extended alignment of the structures.
The new finding showed that by engineering recognition elements between
polymers and fluorinated small molecules, it has been possible to drive their
spontaneous self-assembly from nanometers to millimeters, thanks to the
judicious use of noncovalent interactions. After the processing,
fluoromolecules can optionally be removed upon thermal treatment.
This concept opens up new avenues in large area nanoconstruction, for example
in templating nanowires, which is currently under investigation.
Caption: Schematics and
electron microscopy picture of millimeters aligned self-assembled polymeric
Nature Communications article: “Halogen-bonded
mesogens direct polymer self-assemblies over millimetre length scale” N.
Houbenov, R. Milani, M. Poutanen, J. Haataja, V. Dichiarante, J. Sainio, J.
Ruokolainen, G. Resnati, P. Metrangolo, and O. Ikkala, , Nature Communications
5:4043, doi: 10.1038/ncomms5043 (2014).