Acid form Surlyn(R)/titanate hybrid materials were achieved by polymer in situ sol-gel react,ions for a titanium alkoxide monomer. Atomic force microscopjc images revealed arrays of titania nanoparticles having diameters of 10-30 nm. Fourier transform infrared spectra verified the presence of an internally polymerized itanate phase although unhydrolyzed TiOR groups were present. Carboxylic acid dimerization was complete at room temperature, but,carboxylate anions appeared at higher titanate levels. The methylene rocking doublet persisted upon incorporation, of the inorganic component, which supported the idea of largely undisrupted crystallinity. Thermo- gravimetric analysis showed that the degradation onset-temperature of each hybrid is. largely unaffected by the presence of the inorganic filler, which is consistent with the concept of an isolated titanate phase. The first-scan differential scanning calorimetric thermogram for unfilled Surlyn(R) revealed the usual twin-melting endotherms. In contrast, the primary, high-temperature melting endotherm was seen on the first scan for the Surlyn(R)/titanate hybrids, but the lower temperature endotherm was either not present or weak. Primary melting persisted after several cycles of heating above the melting temperature followed by cooling, demonstrating that primary crystallinity persisted despite titanate phase incorporation.