磁性石墨烯的制备初探

Preparation of Magnetic Graphene

目的制备磁性石墨烯,实现其定向排列,为进一步制备性能良好的热界面材料提供定向导热相。方法采用聚合物包覆和层层组装技术,在石墨烯表面均匀包覆带负电荷的聚磺苯乙烯(PSS)聚电解质层,然后在静电力作用下包覆一层带正电荷的聚二烯丙基二甲基氯化铵(PDDA)聚电解质。最后,借助静电力使带负电荷的磁性Fe3O4纳米粒子在附着有PDDA层的石墨烯表面形成均匀的致密覆盖层,得到磁性石墨烯,并在外磁场作用下使磁性石墨烯进行定向排列。结果采用聚电解质层层组装技术可有效地对石墨烯进行磁性化处理;粉状石墨烯比片状石墨烯定向排列效果明显;以片状石墨烯为原材料的实验条件下,加入聚电解PSS、PDDA的量越多,磁性化效果更佳。结论通过聚电解质层层组装技术可有效地对石墨烯进行磁性化处理,并在磁场作用下实现定向排列。

The work aims to prepare magnetic graphene and achieve its alignment, in order to provide a directional thermal phase for further preparation of well-formed thermal interface materials. By means of polymer cladding and layer-by-layer assembly technique, the graphene surface uniformly was coated with a negatively charged polystyrene sulronate（PSS） polyelectrolyte layer firstly, and then under the action of electrostatic force, it was coated with a layer of positively charged poly diallyldimethyl ammonium chloride（PDDA） polyelectrolyte, and finally by means of an electrostatic force, the negatively charged Fe_3O_4 magnetic nanoparticles formed a uniform dense covering layer on the graphene surface attached with PDDA layer, to obtain magnetic graphene. The magnetic graphene was aligned under the external magnetic field. The results showed that the graphene could be magnetized effectively by the polyelectrolyte layer-by-layer assembly technique. The alignment effect of powdery graphene was better than that of flaky graphene. The more the polyelectrolyte PSS and PDDA were added, the better the magnetic effect was, under the experimental conditions that took flaky graphene as raw material. By using the polyelectrolyte layer-by-layer assembly technique, the graphene can be magnetized effectively and aligned under the action of the magnetic field.