Abstract: “Microemulsion is the promising techniques that can be used to reduce vegetable oil viscosity. In this study, microemulsion-based biofuel consisting of vegetable oil/diesel blends, ethanol and surfactant/cosurfactant mixture were formulated. The goal of this work focuses on the effects of a numbers of ethylene oxide group, EOn (n =1, 5, and 9) in nonionic alcohol ethoxylate surfactant and the effect of cosurfactant structures, straight chain (1-octanol) and branch chain alcohols (2-ethyl-1-hexanol) to reverse micelle microemulsion fuel formation. In addition, biodiesel and bioethanol were used to replace diesel and ethanol, receptively with the aim to formulated microemulsion fuels with absolute bio-based product. The kinematic viscosity which was selected as a key parameter was determined at 40 oC (ASTM D445). The microemulsion aggregate size was investigated as a parameter affecting by numbers of EO groups in nonionic surfactant. The results show that, no observed trend in kinematic v”

Keywords: Biofuel, Microemulsion, Reverse micelles, Palm oil, Cosurfactant, Surfactant, Viscosity