Synthesis, characterization, and relaxometry studies of hydrophilic and hydrophobic superparamagnetic Fe3O4 nanoparticles for oil reservoir applications

Shahid Ali, Safyan A. Khan*, Julian Eastoe, Syed R. Hussaini, Mohamed A. Morsy, Zain H. Yamani

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)

9 Citations (Scopus)
103 Downloads (Pure)


Information acquisition and fluid characterization of oil reservoirs are one of the most challenging and scientifically demanding areas in the oil exploration industry. Herein, we report a single-step solvothermal method for the synthesis of highly-stable hydrophilic and hydrophobic superparamagnetic iron oxide nanoparticles (SPIONs). The functionalization of SPIONs was achieved using polyethylene glycol (PEG-400) and oleylamine (OLA) for water/oil phases of the reservoir, respectively. For comparison, uncoated SPIONs were also prepared by coprecipitation. Stability of hydrophilic SPIONs was monitored in deionized (DI) water and artificial seawater (ASW), while stability of hydrophobic SPIONs was investigated in model oil (cyclohexane-hexadecane 1:1). Several physicochemical techniques were utilized to characterize the phase and functionalization of SPIONs. Transmission electron microscopy (TEM) images display the spherical shape nanoparticles (NPs) having particle diameters 11.6 ± 1.4, 12.7 ± 2.2, and 9.1 ± 3.0 nm for PEG-Fe3O4, OLA-Fe3O4, and Fe3O4, respectively. Spin-spin (T2) relaxation measurements were performed by an Acorn Area analyzer to demonstrate contrasting ability of the contrast agents. The transverse relaxivity (r2) values for PEG-Fe3O4 (66.7 mM−1 s−1) and OLA-Fe3O4 (49.0 mM−1 s−1) were 2.07 and 1.53 times higher than Fe3O4 (32.2 mM−1 s−1) NPs, respectively. The (i) enhanced NMR T2-relaxation with optimum SPIONs concentration, (ii) excellent relaxivity properties due to their ultra-small size, and (iii) long-term stability in various continuous phases, suggest them to be promising T2-contrast agents for oil reservoir applications.

Original languageEnglish
Pages (from-to)133-143
Number of pages11
JournalColloids and Surfaces A: Physicochemical and Engineering Aspects
Early online date6 Feb 2018
Publication statusPublished - 20 Apr 2018



  • Hydrophilic
  • Hydrophobic
  • Superparamagnetic
  • Relaxometry
  • Oil reservoir

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