Sarkar A, Kapoor S, Yashwant G, Salunke H G, Mukherjee T
Radiation Chemistry & Chemical Dynamics Division and Technical Physics and Prototype Engineering Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India.
J Phys Chem B. 2005 Apr 21;109(15):7203-7. doi: 10.1021/jp044521a.
A facile route for in situ synthesis of Co and Ni nanoparticles in a preorganized polyacrylamide gel is reported. Metal-polymer composites were prepared by gamma-irradiation at room temperature. The Co nanoparticles were roughly 3-5 nm in size and were stable in the polymer matrix in the presence of air. The presence of Co and Ni nanoparticles was established by their ability to transfer an electron to methyl viologen {paraquat: 1,1'-dimethyl 4,4'-dipyridinium dichloride; MV(2+) (Cl(-))(2)}. The Co and Ni nanoparticles were probed for their magnetic characteristics by a superconducting quantum interferometer device (SQUID) magnetometer and display a low superparamagnetic blocking temperature T(B) of about 13 and 10 K, respectively. The field-dependent magnetic behavior below T(B) displays the standard features corresponding to superparamagnetism, as expected for very small Co and Ni crystallites. This also suggests that particles are polycrystalline in nature.
报道了一种在预组织的聚丙烯酰胺凝胶中原位合成钴和镍纳米颗粒的简便方法。通过室温下的γ射线辐照制备金属-聚合物复合材料。钴纳米颗粒的尺寸约为3-5纳米，在空气中存在时在聚合物基质中稳定。钴和镍纳米颗粒通过将电子转移给甲基紫精（百草枯：1,1'-二甲基4,4'-二吡啶二氯化物；MV(2+)(Cl(-))(2)）的能力得以证实其存在。通过超导量子干涉仪装置（SQUID）磁力计探测钴和镍纳米颗粒的磁特性，它们分别显示出约13 K和10 K的低超顺磁阻挡温度T(B)。低于T(B)时的场依赖磁行为显示出对应超顺磁性的标准特征，这对于非常小的钴和镍微晶来说是预期的。这也表明颗粒本质上是多晶的。
