The poly-2-hyroxyethyl methacrylate (PHEMA)/clay nanocomposite was synthesized by in Situ atom transfer radical polymerization (ATRP) from initiator moieties immobilized within the silicate galleries of the clay particles. To produce organically modified montmorillonite (MMT) that has ATRP initiator moiety, a new catalyst that consists of quaternary ammonium salt moiety and an initiator moiety was synthesized. This initiator was intercalated into the interlayer spacing of the MMT. The polymerization reaction was carried Out in a mixed solvent system consisting of methyl ethyl ketone and 1-propanol at 50 degrees C, using the initiator that has been already synthesized with a copper bromide catalyst. The 2, 2'-bipyridyl (bpy) complex was used as ligand. The products were characterized via Fourier transform infrared, nuclear magnetic resonance (H-1 NMR, C-12 NMR), transmission electron microscopy, x-ray diffraction. thermogravimetric analysis, and differential scanning calorimetry.