製備具序化結構之FePt磁性奈米粒子

Preparation of FePt Magnetic Nanoparticles with an Ordered Structure

近來磁性奈米粒子的研究廣泛運用在各個領域，如生物醫學應用中的藥物標記、檢測、治療、藥物遞送和磁分離。本研究利用化學還原法製備油溶相FePt磁性奈米粒子，藉由改變表面活性劑油酸：油胺的添加量（5倍、1倍、1/5倍），和比例（1:2、1:0.25），及回流的時間（0.5h、1h、2h），以找出製備具序化結構的FePt磁性奈米粒子之製程參數。再使用巰基乙酸（C2H4O2S）作為相轉換試劑，將油溶性粒子之表面修飾成親水性的官能基。利用FT-IR檢驗FePt磁性奈米粒子，比較轉相前後官能基的差異。使用XRD檢測FePt奈米粒子的晶格結構，結果發現部分實驗參數製備出的奈米粒子不需二次退火就具備序化結構。使用TEM分析粒徑大小，發現製備出的奈米粒子粒徑大約介於2~5nm。VSM檢測FePt奈米粒子結果發現，具有序化結構的FePt奈米粒子飽和磁化量較高，且油溶性粒子經轉相為水溶相後飽和磁化量和矯頑場皆會降低。 Magnetic nanoparticles have been studied for a wide range of research. Nanoparticles are used for biomedical applications, such as for markers, detection, therapy, drug delivery, and magnetic separation. In this study, Oil-phase FePt nanoparticles were synthesized through a chemical reduction method. FePt magnetic nanoparticles with an ordered structure, were obtained by changing the amount of oleic acid and oleylamine added (5×, 1×, and 1/5×) , ratios of oleic acid to oleyamine (1:2 and 1:0.25) , and reflux times(0.5, 1, and 2h) . Oil-soluble particles were modified to water-soluble particles that used thioglycolic acid (C2H4O2S) as a phase transition agent. Functional groups of oil- and water-soluble particles were examined through Fourier-transform infrared spectroscopy. The lattice structures of FePt magnetic nanoparticles were examined through X-ray diffraction spectroscopy. FePt nanoparticles with an ordered structure were prepared without secondary annealing. First, nanoparticles with a size of 2-5 nm were prepared and examined through transmission electron microcopy. The magnetic properties of FePt nanoparticles were detected using VSM. FePt nanoparticles with an ordered structure had higher saturation magnetization. Saturation magnetization and coercivity decreased when FePt nanoparticles were transferred from oil phase to water phase.