Background: Magnetic nanofluid is a special class of nanofluid that exhibits
both magnetic and fluid properties. The main purpose of using magnetic nanofluid as a
heat transfer medium is the possibility of controlling the flow and the heat transfer process
through an external magnetic field. This research aims at identifying the effect of
adding polyethylene glycol (PEG) to magnetite (Fe3O4) nanoparticles for magnetic
Methods: The nanofluid was prepared by synthesizing Fe3O4 nanoparticles using the
chemical precipitation method and then dispersing them in distilled water using a sonicator.
Results: The result of XRD is that nanoparticles had inverse spinel structures, and the
smallest crystallite size is found in the Fe3O4@PEG-6000 samples. FE-SEM and TEM
show that the addition of PEG can reduce the Fe3O4 agglomeration, and the smallest particle
size is found in the Fe3O4@PEG-6000 samples. The result of FT-IR shows that
there is a surface modification of Fe3O4 nanoparticles and PEG polymer. The result of
VSM shows the coercivity value is small; hence, the sample is a superparamagnetic material.
The addition of PEG increases the thermal conductivity of Fe3O4 nanoparticles.
Conclusion: The addition of PEG makes particle size smaller, reduces the agglomeration,
and increases the thermal conductivity, making it useful for magnetic nanofluid applications.