Poly(amino-amide) particles were prepared by reacting 4,4'-diphenyldicarbonyl chloride and 3,3'-diaminobenzidine using a precipitation polymerization method with ultrasonic irradiation. The resulting particles had a narrow size distribution with an average diameter of 334 nm and showed excellent dispersion stability in water. The particles obtained were then modified with silane coupling agents (GPES) by reacting the amino groups of the poly(amino-amide) particles with the epoxide rings of the GPES molecules in N,N-dimethylformamide or N-methylpyrrolidone using di-n-butyltin dilaurate as a catalyst. The amount of GPES covalently bonded to the poly(amino-amide) particles was found to depend strongly on the reaction solvent and catalyst used. The resulting particles showed a narrow size distribution and the connections among the particles were not observed. On the other hand, the particles before and after modification showed different thermal properties and dispersion stability in water. The GPES-modified aromatic polyamide particles were then complexed with ZnO particles with an average diameter of about 20 nm in aqueous acetic acid solution. It was found that the surface of the aromatic polyamide particles was covered with ZnO particles via hydrolysis reaction. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4908-4918, 2009