摘要:
磁响应胶体光子晶体因其具有光子带隙可调、制备简便、响应速度快等特点,在彩色显示、光开关等领域有着重要的应用前景。本文首先采用溶剂热法制备出了Fe3O4/PVP胶体粒子,并利用正硅酸乙酯(TEOS)水解对其表面进行SiO2包覆,得到表面携带负电荷的Fe3O4/PVP/SiO2复合纳米胶体粒子。SEM和TEM测试结果表明,Fe3O4/PVP/SiO2具有单分散特征,平均粒径约为100 nm。VSM测试结果表明,胶体粒子具有超顺磁性,其饱和磁化强度约为26 emu/g。经进一步回流处理后,胶体粒子表面表现明显的负电荷属性,Zeta电势为−48.3 mV。所合成的Fe3O4/PVP/SiO2胶体粒子可在乙腈中均匀分散,所形成的胶体溶液在外加磁场的作用下表现出明亮的结构色,具有明显的磁场可调谐光子带隙特征。
Abstract:
Magnetic responsive colloidal photonic crystals have great potential to be used in color display, light swich etc. due to their performance of tunable photonic band-gap, fast response and easy preparation. In this paper, a solvothermal method was used to prepare Fe3O4/PVP colloidal particles and the particles were then coated with SiO2by TEOS hydrolysis to form Fe3O4/PVP/SiO2 composite particles. SEM and TEM results show that as-prepared Fe3O4/PVP/SiO2 particles possess monodisperse characteristics and the mean particle size is about 100 nm. VSM results show that Fe3O4/PVP/SiO2 particles have superparamagnetism and the saturation magnetization Ms is about 26 emu/g. After refluxing treatment in water, the surface of Fe3O4/PVP/SiO2 particles is negatively charged and the Zeta potential is −48.3 mv. As-prepared Fe3O4/PVP/SiO2 particles can be easily dispersed in acetonitrile to form stable suspensions. Under the magnetic field, the Fe3O4/PVP/SiO2 suspension in acetonitrile displays bright structural color and tunable band-gap features.