Emulsion-templated synthesis method Chem 750 Antony Han University of Waterloo

What is emulsion method? More than 50 years after being known Heterogeneous mixtures –At least one immiscible liquid is dispersed in another in the form of droplets. –At least one of the liquids will be water or an aqueous solution. –Oil-in-water (O/W) –Water-in-oil (W/O) Used in a wide range of common practical application

Ternary phase diagram Typical ternary phase diagram based on oil, surfactant, and water Soft Matter, 2005,1,

Polymerisation of an emulsion in the dispersed phase - colloids in continuous phase - porous materials both phases - composites Soft Matter, 2005, 1,

Emulsion preparation Soft Matter, 2005, 1, Size does matter – in nano world.

Nano-emulsion Non-equilibrium systems – cannot be formed spontaneously Need energy input –High-shear stirring –High-pressure homogenizers –Ultrasound generators

Temperature is critical Current Opinion in Colloid & Interface Science 10 (2005) At high temperature: - macro-emulsion (right) ~1μ m At around 40 ºC: - nano-emulsion (left) ~35 nm

Application TEM micrographs showing (A) SWNT bundles with an adsorbed polystyrene layer in a 8.5% weight SWNT-PS composite and (B) bare Carbolex SWNTs bundles. Nano Lett. Vol. 2, No. 8, 2002, 797

Application Pharmaceutical Research, Vol. 21, No. 8, August 2004, 1428