Temperature anomalies of DEA-CuCl4 and TEA-CoCl2Br2/PMMA nanocomposites

Phase transitions were studied for the new synthesized ferroic (NH2(C2H5)2CuCl4 (DEA-CuCl4) and (NH2(C2H5)4CoCl2Br2 (TEA-CoCl2Br2) nanocrystallites (NC) incorporated into polymer matrices. Comparison with the bulk crystals is performed. A giant temperature shift (from 305.1°C to 360.3°C) of onset temperature for TEA-CoCl2Br2 nanoparticles after their incorporation into the PMMA matrix was found and is substantially larger compared to the DEA-CuCl4. The DSC analysis shows that the temperature of phase transition is crucially dependent on the thermocycling and temperature rate. The principal role of the nano-sized effects is shown. © 2007 Elsevier B.V. All rights reserved.