School of Physics and Astronomy

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Dr Hugo K Christenson

Molecular and Nanoscale Physics Group

Contact details

Room: 8.36
Tel: +44 (0)113 3433879
Email: h.k.christenson @ leeds.ac.uk

Keywords

Crystal growth
Capillary condensation
Biomineralisation
Adsorption
Nucleation
Phase behaviour
Surface forces
Wetting

Research interests

We have shown how amorphous calcium carbonate (ACC), the precursor phase to the biominerals calcite and aragonite, may be stabilised by confinement alone, without the need for specific interactions with biomolecules. In the presence of polymers like polyaspartic acid ACC will enter submicron pores via capillary action. When the ACC eventually crystallises to calcite, single-crystal nanowires of aspect ratios as high as 100 are produced.

We have identified for the first time an amorphous precursor phase to calcium sulphate (bassanite and gypsum). The former of these is an unusual biomineral found in the statoliths of certain jellyfish.

We have recently shown experimentally for the first time that crystal deposition from vapour may proceed without the need for any supersaturation via a two-step mechanism. Supercooled liquid capillary condenses in surface grooves or pits, and nucleation of crystals then occurs in these. Ongoing work is seeking to establish any connection btween capillary condensation and the enhanced nucleation rates often found on surfaces with topographical defects.

I retain an interest in wetting, and work yet to be published has shown how fascinating and beautiful two-dimensional dendritic structures and ordered arrays of crystals may be deposited as salt solutions dewet a smooth surface.

Useful links

personal website
nature
art
science