Nanocomposites containing embedded superparamagnetic iron oxide nanoparticles and rhodamine 6G

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• 作者：Darko Makovec ; Stanislav Č ; ampelj ; Marjan Bele ; Uroš ; Maver ; Milena Zorko ; Miha Drofenik ; Janko Jamnik ; Miran Gaberš ; č ; ek
• 关键词：Nanocomposites ; Superparamagnetism ; Maghemite (γ ; -Fe₂O₃) ; Silica ; Rhodamine 6G ; Traceability
• 刊名：Colloids and Surfaces A: Physicochemical and Engineering Aspects
• 出版年：2009
• 出版时间：20 February 2009
• 年：2009
• 卷：334
• 期：1-3
• 页码：74-79
• 全文大小：614 K

文摘

Bifunctional nanocomposites possessing superparamagnetism and traceability with optical methods were prepared. The superparamagnetic properties were achieved by introducing highly concentrated, ca. 13 nm-sized maghemite (γ-Fe₂O₃) nanoparticles into a silica matrix based on tetraethylorthosilicate (TEOS) and bis-1,2-(triethoxysilyl)ethane (BTSE). Traceability was attained by simultaneously incorporating a small amount of rhodamine 6G fluorescent dye into the same silica matrix. Agglomeration of the highly concentrated maghemite nanoparticles during the preparation procedure was prevented by pre-coating them with a 1–2 nm thick silica layer. The nanocomposites exhibited a relatively high magnetization of 20 emu/g. Superparamagnetism was demonstrated using ZFC and FC measurements. Although the presence of the nanoparticles modified the transparency of the pristine silica matrix, we show that the incorporated rhodamine 6G exhibits a well-resolved, blue-shifted peak in the fluorescence spectrum, with a maximum at about 552 nm. The bifunctionality of the present nanocomposites could be interesting for the preparation of similar materials for biomedical applications.