摘要
This chapter discusses that colloidal solutions are ideal systems to be studied by the small-angle neutron scattering (SANS) technique. This is especially true for the association colloids, such as micelles and microemulsions. The size range of these micellar systems ranges from 30 Å to about 100 Å that, in terms of the scattering experiment, translates into an intensity distribution in the Q range of 0.01 to 0.2 Å-1. This is the most easily accessible range of the SANS spectrometer for which the available neutron flux is also the highest. The resulting simple particle structure factor P(Q), in turn, allows an accurate determination of the interparticle structure factor S(Q) from the measurement. The internal structure of the micellar core, its water content, and its hydrocarbon conformations can also be addressed once the SANS data are properly analyzed. In microemulsions where one has an inverted micellar structure, the effective attractive interaction leads to the cloud point effect or the critical point phenomenon. SANS is a unique tool for simultaneously measuring the structure of the aggregates and their mutual correlations. An important aspect in recent developments of the application of the SANS technique in colloids is the ability to take into account the interaction realistically. An obvious direction to pursue in the future is to explore more of the phase transitions and the structure of the dense phases of these surfactant solutions. © 1987, Academic Press, Inc.