Self-assembly of 6-O- and 6′-O-hexadecylsucroses mixture under aqueous conditions

In this paper, we report the self-assembly of 6-O- and 6′-O-hexadecylsucroses mixture under aqueous conditions. The mixture was synthesized by a five-step sequence from sucrose. The SEM image of a sample prepared by drying a dispersion of the mixture in water showed nanoparticles with the diameter of ∼50 nm and aggregates that were formed by further assembly of them. The XRD measurement of the sample exhibited the diffraction pattern assignable to face-centered cubic (FCC) structure and the diameter of a sphere, which took part in the FCC structure, was calculated to be 5.1 nm. This value was relatively close to that observed in the DLS measurement of a dispersion of the mixture in water and estimated for a spherical micelle based on the molecular sizes of the two sucrose ethers. On the basis of the above findings, the following self-assembly process of the mixture under aqueous conditions was proposed. The mixture formed the spherical micelles with the diameter of ∼5-7 nm in water. The micelles regularly organized according to the FCC structure during the drying process from the aqueous dispersion to construct the nanoparticles with the diameter of ∼50 nm. Several numbers of the nanoparticles further assembled to form the aggregates.