Well defined poly (styrene-co-methylstyrene) grafted polyaniline/organo-modified MgAl layered double hydroxide (LDH) was produced through solution intercalation method. After LDH nanoparticles were modified by the anion exchange reaction of MgAl (Cl) LDH with sodium dodecyl benzene sulfonate, Poly (styrene-co-methylstyrene) copolymers were synthesized by "living'' free radical polymerization and then brominated with N-bromosuccinimide. Afterwards, 1,4-phenylenediamine was linked to brominated copolymers and prepared functionalized copolymer with amine. Poly (St-co-MSt)-g-PANI, has been synthesized by adding solution of ammonium persulfate and p-toluenesufonic acid in DMSO solvent. Finally, Poly (styrene-co-methylstyrene) grafted-Polyaniline/LDH nanocomposites were prepared by solution intercalation method. Characterization of these well-defined nanocomposites included FT-IR, gel permeation chromatography, thermogravimetric analysis, differential scanning calorimeter, transmission electron microscopy, and X-ray diffraction. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 122: 2573-2582, 2011