Studying the growth of silica-surfactant architectures during the formation of mesoporous silicates is pivotal to understand how these materials may be used in catalysts, drug delivery, and nanotechnology. Small-angle neutron scattering (SANS) has been used to study the in-situ formation kinetics of these hierarchical structures. SANS can access a wide enough size range and has sufficient temporal resolution to follow how silica grows around the templating surfactant. Ultra-small-angle scattering and light scattering can access length scales larger than the hundreds of nanometres possible with SANS but, in this case, long data collection times and the turbidity of the solution prevent their use.
Recent developments in spin-echo-SANS techniques now allow studies of structures from hundreds to thousands of nanometres with a time resolution of a few minutes. We have used this approach on Offspec to monitor the condensation and aggregation of silica around surfactant micelles to form larger particles. The final structures were fitted to a sphere model with characteristic radii of approximately 2500 nm.
K J Edler, MJ Wasbrough (Bath University)
Research date: January 2010
Contact: Dr KJ Edler, K.Edler@bath.ac.uk
Further reading: KJ Edler, Soft Matter 2 (2006) 284