title: Effective ultrasonication process for better colloidal dispersion of nanofluid.
abstract: Improving dispersion stability of nanofluids through ultrasonication has been shown to be effective. Determining specific conditions of ultrasonication for a certain nanofluid is necessary. For this purpose, nanofluids of varying nanoparticle concentrations were prepared and studied to find out a suitable and rather mono-dispersed concentration (i.e., 0.5 vol.%, determined through transmission electron microscopy (TEM) analyses). This study aims to report applicable ultrasonication conditions for the dispersion of Al2O3 nanoparticles within H2O through the two-step production method. The prepared samples were ultrasonicated via an ultrasonic horn for 1-5h at two different amplitudes (25% and 50%). The microstructure, particle size distribution (PSD), and zeta potentials were analyzed to investigate the dispersion characteristics. Better particle dispersion, smaller aggregate sizes, and higher zeta potentials were observed at 3 and 5h of ultrasonication duration for the 50% and 25% of sonicator power amplitudes, respectively.
authors.affiliation: Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia.
authors.forename: I M
authors.initials: IM
authors.lastname: Mahbubul
authors.affiliation: Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia. Electronic address: saidur@um.edu.my.
authors.forename: R
authors.initials: R
authors.lastname: Saidur
authors.affiliation: Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia.
authors.forename: M A
authors.initials: MA
authors.lastname: Amalina
authors.affiliation: Department of Mechanical Engineering, Middle East Technical University, Dumlupinar Bulvari, No. 1, 06800 Ankara, Turkey; Eskisehir Osmangazi University, Sivrihisar Vocational School, Mechanics Programme, Eskisehir Cad No. 140, Sivrihisar, Eskisehir, Turkey.
authors.forename: E B
authors.initials: EB
authors.lastname: Elcioglu
authors.affiliation: Department of Mechanical Engineering, Middle East Technical University, Dumlupinar Bulvari, No. 1, 06800 Ankara, Turkey.
authors.forename: T
authors.initials: T
authors.lastname: Okutucu-Ozyurt
keywords: Microstructure; Nanofluid; Particle size distribution; Sonicator amplitude; Ultrasonication duration; Zeta potential