EFFECTS OF SOLVENT AND TEMPERATURE ON THE SIZE OF NICKEL PARTICLES FORMED UNDER THE CONTROL OF POLYMER PSEUDOMATRIX

The effects of reaction medium and temperature on the size of nanopart icles of zero-valent nickel, formed by the reduction of divalent nicke l ions in solutions of poly(N-vinylpyrrolidone), was studied. The aver age size of nickel particles was found to grow both on increasing the temperature during the reduction in water (from 4-7 nm at 20 degrees C to 10-15 nm at 50 degrees C) and upon replacement of water by a water -isopropanol 1 : 1 mixture (up to 5-20 nm at 20 degrees C). The free e nergy, enthalpy and entropy of the polymer-particle interaction were c alculated [at 20 degrees C their values equal to -2.8 x 10(4) J/m(2), -2.5 x 10(-3) J/m(2), and 7.4 x 10(-6) J/(m(2) K), respectively].