|Mesoporous Membranes Templated by a Polymeric Bicontinuous Microemulsion
Tim Lodge, Frank Bates, and their co-advised student Ning Zhou have demonstrated
a new and versatile route to porous materials, with typical channel dimensions
between 50 and 200 nanometers. This work has just appeared in Nano Letters 6, 2354-2357 (2006).
In this work a bicontinuous microemulsion was prepared from a mixture of
polystyrene, polyisoprene, and a poly(styrene-b-isoprene) diblock copolymer
surfactant. At room temperature the glassy polystyrene maintained the structure,
while gaseous sulfur chloride was used to cross-link the polyisoprene domains.
The polystyrene phase was then removed simply by solvent extraction. The
porosity was characterized by SAXS and by BET analysis. After backfilling
the pores with an ionic liquid, the resulting ionic conductivity proved the
continuity of the pore structure through a 1 mm thick sample. A scanning
electron micrograph of the material is shown in the figure.