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báo cáo hóa học: " The investigation of frequency response for the magnetic nanoparticulate assembly induced by time-varied magnetic field"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: The investigation of frequency response for the magnetic nanoparticulate assembly induced by time-varied magnetic field | Sun et al. Nanoscale Research Letters 2011 6 453 http www.nanoscalereslett.eom content 6 1 453 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access The investigation of frequency response for the magnetic nanoparticulate assembly induced by time-varied magnetic field Jianfei Sun1 2 Yunxia Sui3 Chunyu Wang1 2 and Ning Gu1 2 Abstract The field-induced assembly of g-Fe2O3 nanoparticles under alternating magnetic field of different frequency was investigated. It was found that the assembly was dependent upon the difference between colloidal relaxation time and field period. The same experiments on DMSA-coated g-Fe2O3 nanoparticles exhibited that the relaxation time may be mainly determined by the magnetic size rather than the physical size. Our results may be valuable for the knowledge of dynamic assembly of colloidal particles. Keywords magnetic field dynamic assembly pattern formation magnetic nanoparticles Background With the expanding application of magnetic nanoparticles in cellular culture-matrix and tissue engineering the interaction between nanomaterials and cells is becoming a central issue 1 2 . The assembly of magnetic nanoparticles will play an important role in the issue because the colloidal behavior can be greatly affected by the assembled morphology. Very recently the time-varied alternating magnetic field got reported to be capable of inducing the assembly of iron oxid e nanoparticles. It was discovered that Fe3O4 nanoparticles can form the fibrous assemblies in the presence of 80-KHz or 50-Hz alternating magnetic field 3 4 . The results also showed that the mechanism of colloidal assembly induced by the alternating magnetic field is essentially different from that induced by the static magnetic field which may result from the variety in time domain. Thus the frequency response of colloidal assembly directed by time-varied magnetic field is imperative to study. However there has been little report on this topic. In this paper .