Controlling of dielectric parameters of insulating hydroxyapatite by simulated body fluid

Abstract

Hydroxyapatite (HAp) samples were synthesized under various amounts of citric acid using the sol-gel method. Before and after immersion in simulated body fluid (SBF) for 14 and 28 days, the structural properties of HAp samples were analyzed by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy with energy dispersive X-ray (EDX) spectroscopy and dielectric measurements. The crystallite size (D) was found to be in the range of 25.17-33.06 nm with the crystallinity percent (X-C%) of 69.53-86.09. The lattice parameters of a and c were calculated to be in the ranges of 9373-9.434 angstrom and 6.828-6.896 angstrom, respectively. The morphology of the as-synthesized samples was changed with the amount of citric acid and soaking period in SBF. The Ca/P molar ratios indicated a decrease with increasing immersion time, and Ca-deficiency was observed. The relative permittivity (epsilon') and dielectric loss (epsilon '') were significantly affected by citric acid content and soaking period in SBF. It wasP seen that the alternating current conductivity (sigma(ac)) increased with increasing frequency and the crac values changed with increasing soaking period and amount of citric acid. (C) 2014 Elsevier B.V. All rights reserved.