title: 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 (XC%) of 69.53-86.09. The lattice parameters of a and c were calculated to be in the ranges of 9.373-9.434 Å and 6.828-6.896 Å, 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 (ε') and dielectric loss (ε″) were significantly affected by citric acid content and soaking period in SBF. It was seen that the alternating current conductivity (σac) increased with increasing frequency and the σac values changed with increasing soaking period and amount of citric acid.
authors.affiliation: Department of Physics, Faculty of Science, Firat University, Elazig, Turkey. Electronic address: okaygili@firat.edu.tr.
authors.forename: Omer
authors.initials: O
authors.lastname: Kaygili
authors.affiliation: Department of Chemistry, Faculty of Science, Firat University, Elazig, Turkey.
authors.forename: Serhat
authors.initials: S
authors.lastname: Keser
authors.affiliation: Department of Physics, Faculty of Science, Firat University, Elazig, Turkey.
authors.forename: Tankut
authors.initials: T
authors.lastname: Ates
authors.affiliation: Department of Physics, Faculty of Science, Firat University, Elazig, Turkey.
authors.forename: Cengiz
authors.initials: C
authors.lastname: Tatar
authors.affiliation: Department of Physics, Faculty of Science, Firat University, Elazig, Turkey.
authors.forename: Fahrettin
authors.initials: F
authors.lastname: Yakuphanoglu
mesh_terms: D002118:Calcium; D019343:Citric Acid; D017886:Durapatite / Q000737:chemistry*; D004553:Electric Conductivity; D008954:Models, Biological; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D014961:X-Ray Diffraction
chemical_list: D019343:Citric Acid; D017886:Durapatite; D002118:Calcium
keywords: Citric acid; Crystal structure; Crystallinity percent; Hydroxyapatite; In vitro