Small Angle and Surface Scattering

IUCr Newsletter (1998). 6(4), 9.

Australian facilities for small angle X-ray (SAXS) and neutron (SANS) scattering and reflectometry are expanding. Forty scientists whose interests ranged from biology through chemistry, physics and materials science to engineering attended the first small angle and surface scattering meeting held at the Australian Nat'l U. (ANU) in April 1998. These techniques are used to examine the detailed structure of condensed matter on scales from about 1 to 100 nanometers in the supramolecular nanostructure range. By use of isotropic substitution or tuning the wavelength it is possible to selectively highlight different components in bulk materials and all types of surfaces and to follow chemical reactions and microstructure and texture formation at a scale inaccessible to ordinary microscopy or light scattering. New instruments now available include an X-ray reflectometer at the Research School of Chemistry; two more SAXS machines at ANU and the U. of South Australia; and a SAXS/Grazing incidence X-ray diffraction on "BigDiff" at the Australian Nat'l Beamline Facility, Tsukuba. Applications from the area of materials included studies of templated mesoparticles silicates, titania/zirconia nanoparticies, composite films of silica and organic surfactants, colloidal silica, and quantum well semiconductor devices. More direct applications to petroleum geology, domains in wood pulps, and activated carbons for water treatment were presented. The meeting left a clear impression that with the new apparatus these techniques can provide a new view of structure in a range in the past thought too large for chemistry but too small for engineering.

Philip Reynolds