Microemulsions with Didodecyldimethylammonium Bromide Studied by Neutron Contrast Variation

摘要: Abstract The structure of water-in-oil microemulsion droplets, stabilized by didodecyldimethylammonium bromide (DDAB), has been investigated small-angle neutron scattering (SANS). Detailed information about the curved surfactant film obtained selectively deuterating water, DDAB, and cyclohexane components. For each surfactanth-DDAB andd-DDAB concentration, three sets complementary contrast data were analyzed together in terms a Schultz distribution core–shell particles. modeling was consistent with simple liquid-like layer, density 0.80 g cm−3, no evidence for any solvent penetration. This thickness found to be 11–12 A, 70% an all-transC12chain length. At water interface area per head 56–61 A2, while alkyl chains at outer surface it 90–125 A2(15–30% lower than that truncated cone molecular configuration). cyclohexane–water interfacial tensions γo/w, measured light scattering, used along droplet polydispersities find rigidity DDAB film, 2K+Kis close 1.0kBT. means rather acting as effective parameter SANS analysis, polydispersity is natural consequence rigidity. These results show bending energy model accounts well behavior such microemulsions.