Properties and Structures of Aerosols (IB, AY, MA, OT) in Water and Organic Solvents

The solution states and conformations of Aerosol IB, AY and MA were investigated by surface-tension measurements, heat-of-dilution measurements and a 1H- and 13C-NMR study, and compared with those of Aerosol OT. It was suggested that in water two hydrocarbonchains of Aerosol IB shorter than those of Aerosol OT aggregate with each other by hydrophobic interaction both in monomeric state and in micellar state as similarly as the chains of Aerosol OT. In chloroform, on the other hand, Aerosol IB has a different conformation from that of Aerosol OT. Aerosol IB has two steps in micellization or it forms the 1 st and 2 nd micelles (aggregates) . The 1 st micelle has an association number of 2 or 3. The 1 st CMC is about 0.2 mol.kg-1. For the 2 nd micelle, the association number could not be determined exactly at present but estimated as less than 10, and the CMC was evaluated as 1 mol.kg-1. The dynamic behaviors of Aerosol IB, AY and MA in monomeric state and micellar state were discussed on the basis of 13C-NMR spin-lattice relaxation time T1. The correlation time of micelles calculated from T1 and the time from the viscosity of solvent agreed well with each other for the micellar shapes approximated to be ellipsoidal.