Mechanisms of highly stabilized ex-situ oleic acid-modified iron oxide nanoparticles functionalized with 4-pentynoic acid

Baharuddin, Aainaa Aqilah and Ang, Bee Chin and Abu Hussein, Nurul Athirah and Andriyana, Andri and Wong, Yew Hoong (2018) Mechanisms of highly stabilized ex-situ oleic acid-modified iron oxide nanoparticles functionalized with 4-pentynoic acid. Materials Chemistry and Physics, 203. pp. 212-222. ISSN 0254-0584, DOI

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In this paper, the main objective is to successfully functionalize 4-pentynoic acid on iron oxide nanoparticles (NPs) which arises second objective; to ex-situ modify different concentrations of oleic acid on the NPs. A new understanding has been achieved as to how the concentrations of oleic acid prior ex-situ modification, play a major role in the successful functionalization of 4-pentynoic acid on the NPs. The functionalization proposed is a potential alternative route of creating an acid anhydride from two carboxylic acids without the use of dehydrating agent. Unmodified NPs were synthesized by co-precipitation method and were altered to pH 12 using NH4OH to promote dispersity right before ex-situ modification with oleic acid (0.2–0.8 wt % oleic acid to iron oxide) and subsequent 4-pentynoic acid (1.63 × 10−3 mol) functionalization. Characterizations were conducted by X-ray-diffraction (XRD), Transmission Electron Microscopy (TEM), Thermogravimetric and Differential Thermal analysis (TGA-DTA), Fourier transform infrared spectroscopy (FTIR), proton nucleic magnetic resonance (NMR) and Zetasizer. A monolayer oleic acid is produced for ex-situ modification of 0.2 wt % oleic acid to iron oxide. Whereas the higher concentrations of oleic acid ex-situ modifications generate bilayer oleic acid-modified iron oxide NPs to which, functionalization of 4-pentynoic acid is only successfully performed. The samples pose highly stabilized dispersions at pH 12 varying between -42 and -75 mV, whereas the mean hydrodynamic particle size distributions are achieved at approximately 35–48 nm. Mechanisms of ex-situ modifications of different oleic acid concentrations and functionalization of 4-pentynoic acid on the iron oxide NPs at pH 12 and 333.15 K are also proposed.

Item Type: Article
Funders: University of Malaya: Research Grant (UMRG) Programs ( RP024A-13AET and RP034C-15AET ) and Postgraduate Research Grant (PPP) ( PG151-2015A ), Ministry of Science, Technology and Innovation Malaysia through Science Fund ( SF011-2015 ), Ministry of Higher Education Malaysia through Fundamental Research Grant Scheme (FRGS) ( FP010-2013B ) and High Impact Research Grant (MOHE-HIR D000008-16001 )
Uncontrolled Keywords: Ceramics; Precipitation; Magnetic materials; Oxides; Acid anhydride
Subjects: T Technology > TJ Mechanical engineering and machinery
T Technology > TP Chemical technology
Divisions: Faculty of Engineering
Depositing User: Ms. Juhaida Abd Rahim
Date Deposited: 17 Sep 2019 06:08
Last Modified: 17 Sep 2019 06:08

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