Current Interests

Prof. Julian Eastoe

Photo-surfactants

If a surfactant molecule contains a suitable chromophore, thereby giving it isomer-dependent properties, illumination can be used to affect adsorption and aggregation.  We have developed highly optimised photo-surfactants, and some exciting new results are shown below.  These may be considered as the next generation of surfactants, with added functionality and tuneability. 

Photo-active systems revolutionise surfactants from mundane everyday molecules, into sophisticated additives, which can perform key functions in various areas, for example targeted delivery of drugs and carrier liquids, printing and surface coating.

CO₂-active surfactants

Owing to its accessible critical point (31.1 °C and 73.8 bar) CO₂ has significant environmental and economic advantages over currently used solvents. However, weak intermolecular forces in CO₂ result in very low solubility of polars.  Formation of a water-in-CO₂ (w/c) microemulsion or emulsion is one way of overcoming the problem, but this necessitates developing specialised CO₂-compatible surfactants.  Fluorocarbons are very effective_, but impractical for real applications owing to their high cost.  We have designed more economic hydrocarbons (A and B below) to be CO₂-active; these are analogues of the well-known AOT, which is insoluble.  The terminal t-butyl groups give the surfactants sufficiently low surface energies, making them CO₂-soluble.  This finding opens the door to new cost-effective surfactants for these applications.

Polymerisable surfactants

A central theme in materials chemistry is template-directed fabrication of nano-structured architectures.  We have developed new self-assembled organic phases, made from reactive surfactant monomers (surfmers).  These compounds bear polymerisable chains and/or counterions which can be used to “zip up” aggregates without destroying their initial nanostructure, providing optimised reaction templates.  Shown below are cylindrical nano-particles of BaSO₄, which have been grown in encapsulated rod-shaped microemulsion droplets, stabilised by a partially polymerised monolayer.  The ideas are quite general and can be applied in any region of the surfactant phase diagram.