控制羧基数改性的水分散性 Fe3O4 纳米颗粒用于磁感应加热,ACS Applied Nano Materials

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控制羧基数改性的水分散性 Fe3O4 纳米颗粒用于磁感应加热
ACS Applied Nano Materials ( IF 5.3 ) Pub Date : 2021-07-07 , DOI: 10.1021/acsanm.1c01370
Takehiro Yachi ₁ , Masaki Matsubara _{1,

2} , Chen Shen ₁ , Shunya Asami ₁ , Nathalie B. Milbrandt ₃ , Minseon Ju ₃ , Sameera Wickramasinghe ₃ , Anna Cristina S. Samia ₃ , Atsushi Muramatsu ₁ , Kiyoshi Kanie ₁

Affiliation

通过在所制备的油基封端的 Fe ₃ O ₄ NPs表面上引入羧基 (-COOH)，制备了具有优异水分散性和稳定性的单分散 Fe ₃ O ₄纳米粒子 (NPs) 。COOH 部分在 NP 表面的受控引入是通过简单的配体交换反应进行的，该反应使用两种类型的具有十二烷基部分和末端 COOH 基团的膦酸配体。通过调节两种膦酸的摩尔比来控制颗粒表面 COOH 基团的改性程度。在配体交换反应过程中，Fe ₃ O ₄的晶体结构和形貌没有发生变化。NP。傅里叶变换红外 (FT-IR) 光谱的结果证实这两种配体通过其磷酸官能团与 Fe ₃ O ₄ NP 表面结合。两种配体的表面覆盖率和摩尔比分别通过热重分析 (TGA) 和质子核磁共振 ( ¹ H NMR) 测量进行评估。从热分析获得的结果与反应中使用的配体的初始摩尔比一致，这反映了所开发的配体交换过程的效率。我们的 COOH 改性 Fe ₃ O ₄纳米颗粒可以通过去质子化在水中分散 6 个月以上，并且在不添加其他表面活性剂和分散剂的情况下表现出典型的铁磁流体行为，表现出高分散稳定性。此外，评估了水分散体中Fe ₃ O ₄ NPs的磁感应加热性能，并且比吸收率 (SAR) 值估计为 38.3 W/g Fe。这些结果表明，我们的 COOH 修饰的 Fe ₃ O ₄ NPs 具有所需数量的 COOH 表面部分，有利于精确表面设计、水基铁磁流体和热疗等应用。

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Water-Dispersible Fe3O4 Nanoparticles Modified with Controlled Numbers of Carboxyl Moieties for Magnetic Induction Heating

Monodisperse Fe₃O₄ nanoparticles (NPs) with excellent water dispersibility and stability were prepared by the introduction of the carboxyl group (−COOH) on the surface of the as-prepared oleyl-capped Fe₃O₄ NPs. Controlled introduction of the COOH moieties on the NP surface was carried out by a simple ligand exchange reaction using two types of phosphonic acid ligands with dodecyl moiety and the terminal COOH group. The degree of modification of the COOH group on the particle surface was controlled by tuning the molar ratios of the two phosphonic acids. During the ligand exchange reaction, no change was observed in the crystal structure and morphology of the Fe₃O₄ NPs. The results of Fourier transform infrared (FT-IR) spectroscopy confirmed that the two ligands were bound to the Fe₃O₄ NP surface through their phosphoric acid functional groups. The surface coverage and molar ratios of the two ligands were evaluated by thermal gravimetric analysis (TGA) and via proton nuclear magnetic resonance (¹H NMR) measurements, respectively. Results obtained from the thermal analyses were consistent with the initial molar ratios of the ligands used in the reaction, which reflect on the efficiency of the developed ligand exchange process. Our COOH-modified Fe₃O₄ NPs could be dispersed in water by deprotonation for over 6 months and exhibit a typical ferrofluid behavior without the addition of other surfactants and dispersants, showing high dispersion stability. Furthermore, the magnetic induction heating performance of the Fe₃O₄ NPs in aqueous dispersions was evaluated and the specific absorption rate (SAR) value was estimated to be 38.3 W/g Fe. These results suggest that our COOH-modified Fe₃O₄ NPs with the desired number of COOH surface moieties can be advantageous for applications such as precise surface design, water-based ferrofluid, and hyperthermia treatment.

更新日期：2021-07-23

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