Scattering microemulsion characterisation

Baker, R.C. Florence, A.T. Ottewill, R.H. Tadros, T.F. Investigations into the formation and characterisation of microemulsions 2. Light scattering, conductivity and viscosity studies of microemulsions. J. Colloid Interf. Sci. 1984, 100, 332-349. 

However, the structure and composition of microdroplets in which the reaction takes place are not the only parameters controlling polymerisation. We shall see later that particles in the initial microemulsion cannot be considered as independent reactors since interparticle interactions play an important role. Small angle light and neutron scattering experiments have shown that these interactions are attractive [6.20]. There is a clear increase in these attractive interparticle forces as the proportion of acrylamide is raised. In particular, this has two consequences the second virial coefficient of osmotic pressure takes negative values the peak in the structure factor which characterises a hard sphere system is no longer present. 

Microlatexes have been characterised by means of various techniques, including light scattering, viscosity, and electron microscopy. Unlike alcohol-based microemulsions, which raise many problems of dilution, microlatexes are easy to dilute, behaving like suspensions of hard spheres, without strong interaction between particles. After polymerisation, attractive forces due to the monomer-cosurfactant at the interface are considerably reduced (see above). 

Details are given of a number of indirect techniques for characterising droplet or particle sizes before and after PS polymerisation without diluting the system. Data from small angle neutron scattering on PS microemulsions are presented. 15 refs. 

Characterisation of Microemulsions Using Scattering Techniques 327 where K is the scattering vector,... 

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