Ion pair self-assembly composed of polyamidoamine dendrimer and phenylthio acetic acid and its temperature and oxidation-responsive release property

Polyamidoamine (PAMAM) dendrimer/phenylthio acetic acid (PTA) ion pair could be generated when the amino/carboxyl group ratio was 3/7 to 1/9. The chemical shifts on 1H NMR and FT-IR spectra suggested that PTA interacted ionically with PAMAM. The PTA was oxidized to sulfoxide and sulfone by H2O2, evidenced by 1H NMR and FT-IR spectroscopy. The ion pair exhibited upper critical solution temperature (UCST) and air/water interface-active which could decrease upon PTA oxidation. When the medium temperature was higher than the UCST, the substantial release of dye loaded in IPSAM took place in the H2O2 solution.