KAJIAN SIFAT DIELEKTRIK PADA NANOPARTIKEL MAGNETITE (Fe3O4) YANG DIENKAPSULASI POLIMER POLYETHYLENE GLYCOL (PEG-4000); STUDY ON THE DIELECTRIC PROPERTIES OF MAGNETITE NANOPARTICLES ( Fe3O4 ) ENCAPSULATED WITH POLYMER POLYETHYLENE GLYCOL ( PEG - 4000 )

Heriansyah, Edi Suharyadi

2015 | Disertasi | FMIPA

Dielectric properties of nanoparticles Fe3O4 encapsulated with polymer polyethylene glycol (PEG-4000) have been studied under various concentration 0%, 20%, 33%, 50% and 75% in the frequency range 10-120 kHz. Dielectric properties measured by impedance spectroscopy, and The result was real dielectric constant (?r’), imaginary dielectric (?r”), loss tangent (Tan ?) and impedance. Dielectric constant decreased rapidly with increasing frequency because of the interfacial polarization, this phenomena corresponding to the twolayer model as predicted Maxwell-Wagner. The dielectric properties Fe3O4 encapsulated with PEG were explained considering the Debye relaxation plot. The Dielectric constant decreases as the increase concentration of PEG. At the frequency 10 kHz, dielectric constant of the sample with 33% and 50% concentration PEG is 252.5 and 208.6 respectively. This occurred because the bigger grain size more conductive than the small one. The imaginary dielectric constant decreases as the increase concentration of PEG. At frequency 10 kHz, sample with 33% concentration PEG has a value 108,2 and sample with 50% PEG has a value 82,3. Besides that, found the influence of the other phases that appear on the synthesis of nanoparticles Fe3O4 encapsulated with PEG to the dielectric properties. The loss tangent decreases as the increase of frequency. Loss tangent decrease as increase concentration of PEG, at frequency 10 kHz sample with 33% concentration PEG has a value of 0,43 and sample with concentration of 75% PEG has a value of 0,35. The impedance increases as the increase of PEG concentration. The increased impedance is assumed contributes grain boundaries more dominant due to the addition of PEG concentration. Large impedance values of samples with a concentration of 33% PEG has a value 233.3 k? and increases as the concentration of PEG 75% with a value of 285.9 k? impedance.

Kata Kunci : dielectric; impedance; loss tangent; co-precipitation, nanoparticles; Fe3O4; encapsulation; polyethilene glycol (PEG)