The structures of emulsions formed from mixed oil-soluble and water-soluble amphiphiles (respectively derivatives of polyisobutylene, PIBSA, and polyacrylamide, PAM) will be investigated at three temperatures. Scattering contrasts of three of the four components (oil, aqueous, PAM) are available by deuteration to give eight contrasts. This will allow the independent determination of the structure and content of the aqueous-oil interface, and the micelle compositions in the oil and aqueous phases. The results from these measurements will shed light on the competition between the oil-soluble and water-soluble surfactants at the common interface, and how the co-surfactancy impacts on emulsion stability.