For twenty years scientists have been searching for surfactants able to solubilise water nano-domains in supercritical carbon dioxide, scCO2 (as water-in-scCO2 microemulsions, W/scCO2 μE) into which larger polar molecules can be dissolved. To date the most successful CO2-phillic surfactants contain fluorocarbon chains as tail groups. However, these are expensive and environmentally unfavourable and so there is much interest in designing low fluorine/hydrocarbon replacements. A novel series of surfactants containing four hydrocarbon chains selected to be known CO2-philic groups have been synthesised and initial experiments show them to be promising candidates for water-in-CO2 microemulsion formation. The proposed experiment aims to elucidate the self-assembly of these surfactant in scCO2 using the only viable technique, small-angle neutron scattering.