کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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596213 | 1454038 | 2009 | 6 صفحه PDF | دانلود رایگان |

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.
Journal: Colloids and Surfaces A: Physicochemical and Engineering Aspects - Volume 334, Issues 1–3, 20 February 2009, Pages 74–79