The influences of the concentration and generation of polyamidoamine dendrimer, the ratio of dodecanoic acid to toluene, and pH in the water phase on the extraction yield of helianthine were systematically studied by selecting helianthine as the guest molecule and electrostatic self-assembled PAMAM as the host. The experimental results show that the extraction yield of helianthine increased with the increase of the generation and concentration of the polyamidoamine dendrimer. When the mass ratio of dodecanoic acid to toluene was 1∶10, pH value was 7.3, the extraction yield of helianthine was the maximum. When the concentrations of 1.0, 2.0 and 3.0 generations of polyamidoamine dendrimer were all 0.21 mmol/L, their self-assembled dendrimers of 1.0, 2.0 and 3.0 generations of polyamidoamine dendrimer with dodecanoic acid exhibited the corresponding maximal extraction yields of helianthine, i.e., 6.04%, 41.61% and 68.50%, respectively. The action mechanism of the host-guest molecule in the phase transfer system is analyzed.
Three polyamidoamine(PAMAM) dendrimers have been synthesized by divergence method with ethylenediamine as core. The surface tensions of aqueous solution of different generation PAMAM were determined by traditional surfactant method. The results showed that the whole PAMAM doesn′t have surface acti- vity and the half PAMAM have certain surface activity. Their critical micelle concentrations(CMC) were obtained from surface tension curves, and the hydrophile-lipophile balance number(HLB), saturated adsorption capacity, molecular cross section area and molecular diameter were calculated. The results revealed that the molecular diameter of 0.5G, 1.5G and 2.5G PAMAM were 0.743, 0.998 and 1.371 nanometer, respe- ctively. The dendrimer obtained was also proved to be of nanometer order.
