The aggregation behavior of meso-tetrakis(4-hydroxyphenyl) porphyrin (THPP) in hyperbranched poly(amide-ester)s (HBP) solution was investigated by UV-vis and fluorescence spectra. The absorption at 434 nm in THPP was blue-shifted to 425 nm, and the absorption intensity increased with the addition of HBP. The results showed that the J-type aggregation of THPP was effectively distacked by hyperbranched poly(amide-ester) in the neutral phosphate buffer solution. In acid solution, the hypsochromic shift from 447 nm to 424 nm exhibited the presence of H₂THPP with the addition of HBP, which showed the equilibrium H₂THPP H₄THPP^2＋. In basic solution, the hydroxy in THPP resulted into the oxide ions, which improved the solubility in water. The absorption and FL intensity of THPP increased with addition of HBP.

Key words: hyperbranched poly(amide-ester)s, meso-tetrakis(4-hydroxyphenyl) porphyrin, aggregation behavior