Covalently closed microemulsions in presence of triblock terpolymers

更新日期：2009-05-04 瀏覽次數(shù)：3035

Abstract：
This paper is focused on the influence of polystyrene （PS）–poly（1,4-butadiene）（PB）–poly（ethylene oxide）（PEO） triblock terpolymers on the w/o microemulsion of the pseudo-ternary system water/sodium dodecylsulfate （SDS）/xylene-pentanol. Despite the insolubility of the copolymer in
water as well as in the xylene–pentanol mixture, it can be incorporated into the w/o microemulsion and interactions between the triblock terpolymer molecules and the anionic surfactant headgroups can be detected by differential scanning calorimetry （DSC） measurements. Furthermore, dynamic
light scattering measurements were used to determine the aggregate diameter of the modified microemulsions. For lower polymer concentrations large aggregates between 100 and 500 nm can be observed. Surprisingly, at a higher terpolymer concentration of 5 wt%, significant smaller
aggregate diameters can be identified by dynamic light scattering and Cryo-SEM. One can conclude that the copolymers are incorporated in the inverse microemulsion droplets, where the PB blocks cover the water droplets. The thermally induced radical cross-linking of the butadiene units in the presence of azobisisobutyronitrile （AIBN） leads then to covalently closed nanocapsules with an average size of 10 nm.
Keywords：Triblock terpolymer; Microemulsion; Nanocapsules

上一篇：Thermophysical properties of 1-hexyl-3-methyl imidazolium based ionic liquids with tetrafluoroborate
下一篇：Effect of Permeability on Aqueous Biopolymer Interfaces in Spinning Drop Experiments