超顺磁性γ-Fe_2O_3纳米线的制备

Fabrication of Superparamagnetism γ-Fe_2O_3 Nanowires

通过硬质氧化法制备了孔径为150 nm,孔间距为230 nm的氧化铝模板。采用共沉淀法合成了具有超顺磁性的γ-Fe_2O_3纳米颗粒,其平均直径为8 nm。通过自下而上的组装工艺,将聚丙烯酸改性后带负电荷的γ-Fe_2O_3纳米颗粒和带正电荷的阳离子聚电解质聚合物在氧化铝模板的孔洞中组装成γ-Fe_2O_3纳米线阵列,并用SEM观察其形貌。采用振动样品磁强计(VSM)测得所制备的纳米线阵列的剩磁和矫顽力接近于零,说明该纳米线阵列具有超顺磁性。

First,anodic aluminum oxide（ AAO） membranes with a 150 nm diameter and a 230 nm interpore distance and superparamagnetism γ-Fe_2O_3 nanoparticles with 8 nm average diameter were prepared using hard anodization process and coprecipitation method,respectively. Then,the anionic γ-Fe_2O_3 nanoparticles by polyacrylic acid modification and cationic polymers were co-assembled into γ-Fe_2O_3 nanowire arrays in the pores of AAO membranes through a bottom-up assembly process. At last,the morphology of γ-Fe_2O_3 nanowire arrays was characterized by SEM. The remanence and coercivity of the nanowire arrays were nearly zero by means of a vibrating sample magnetometer（ VSM）,which showed that the γ-Fe_2O_3 nanowire arrays inherited the superparamagnetism behavior of single nanoparticles.