Competitive Supramolecular Encapsulation of Amphiphilic Hyper- branched Polymers Made from A2 and BB’2 Type Monomers. 1. Polyaddi- tion of 1-(2-aminoethyl)piperazine to Divinyl Sulfone

The competitive host-guest encapsulations of palmityl chloride-modified amphiphilic hyperbranched poly(amido-amine) (HPAMAM-PC) and poly(sulfone-amine) (HPSA-PC) to selected pairs of dyes are reported. Watersoluble and chloroform-insoluble dyes, such as methyl orange (MO), methyl blue (MB), rose bengal (RB), fluorescein sodium (FSS), eosin Y (EY) and phloxine B (PB), can be transferred from aqueous phase into chloroform phase by the HPAMAM-PC and HPSA-PC. UV/Vis spectra were used to determine the loading capabilities (Cloads) of different dyes in the case of single-dye encapsulations (Exp I). Four pairs of dyes: (1) MO and RB, (2) MO and PB, (3) MO and EY, (4) MO and FSS, were chosen to perform comparative experiments to investigate the influence of competitive interactions on the Cloads of dye pairs. As a result, in the cases of one-step double-dye encapsulations (Exp II) and gradual double-dye encapsulations (Exp III), we found three kinds of competitive relationships: (1) The Cload of MO decreased significantly in the presence of either RB or PB, compared with the Cload in the single-dye encapsulation, while the existence of MO did not affect the encapsulations to RB and PB greatly, (2) the Cloads of both dyes decreased if they were encapsulated simultaneously by HPAMAM-PC or HPSA-PC (MO & EY), (3) FSS can hardly be encapsulated by the hyperbranched polymers with the existence of MO in the aqueous solution. 1 H NMR, FTIR and thermogravimetric analysis (TGA) were used to confirm the resulting competitive encapsulations. Relatively selective constant to MO (Rdye/MO) was defined to measure the competitive ability of each dye to MO quantitatively. The competitive abilities of RB, PB were larger than that of MO, while EY almost equal to MO and FSS lower than MO. The size of the dye molecules, electrostatic acid-base interactions between the dye molecules and the polymers, the interaction between different dyes were considered to be the main causes of the results.