缩合法合成磁性荧光高分子CdTe@Fe_3O_4/P(NIPAM-co-AA)复合微球及其表征

具有超顺磁性和荧光特性的CdTe@Fe_3O_4/P(NIPAM-co-AA)多功能复合微球是以P(NIPAMco-AA)为模板制备而成.首先,采用溶胀法使模板微球带有磁性;其次,辅助TEOS和APTES两种化学试剂实现对Fe_3O_4/P(NIPAM-co-AA)微球表面的氨基功能化;最后,携带氨基的磁性微球与巯基乙酸修饰的CdTe量子点通过酰胺缩合反应,将量子点键合到磁性微球表面上,最终获得单分散的磁性荧光高分子复合微球.分别采用扫描电子显微镜、透射电子显微镜、倒置荧光显微成像系统、荧光分光光度计以及振动样品磁强计等方法对所获复合材料的结构与性能进行了表征.结果表明:复合微球单分散性良好,平均粒径约为30μm,饱和磁化强度可达5.4emu/g,具有良好的超顺磁性和较高的荧光发光效率.该材料将磁性、荧光结合到微米级高分子共聚物上,不仅解决了纳米粒子分离和处理的困难,而且奠定了多功能材料在生物标记、荧光成像等诸多领域潜在的应用基础.

Synthesis of Magnetic Fluorescent CdTe@Fe3O4/P(NIPAM-co-AA) Polymeric Composite Microsphere by Amide Condensation Reaction

This work synthesizes a large class of multifunctional CdTe@Fe3O4/P(NIPAM-co-AA) composite microspheres with superparamagnetic and fluorescent properties by using the polymer template method.The P(NIPAM-co-AA) microspores are obtained by inverse suspension emulsion polymerization.Magnetic nanoparticles were doped into the networks of the polymer template microspheres by a simple swelling method.TEOS and APTES were chosen to achieve amino-functionalization of the magnetic microsphere surface.Furthermore, mercaptoacetic acid modified-CdTe quantum dots reacted with amino functional microsphere, which finally resulted in the mono-dispersed magnetic fluorescent polymeric microspheres.Several techniques, e.g.scanning electron microscope, transmission electron microscopy, fluorescence microscopy and fluorescence spectrophotometer, etc.were used to examine structures and properties of the resulting composites.In summary, the resulting composite microspheres are as large as about 30 μm and exhibit excellent superparamagnetism and high efficient fluorescence quantum yield.The saturation magnetization reaches 5.4 emu/g.This approach to generating multifunctional composite microspheres by combining the magnetism and fluorescence onto micrometer copolymers could not only avoid difficulties in separation of nano-particles, but also lay bases for many potential applications in various fields.