Hydroxyapatite (HA) nanorods were synthesized by hydrothermal process using anhydrous CaCl2 and (NH4)(2) HPO4 as raw materials, urea was used as a homogeneous precipitation agent ; hexadecyltrimethy ammonium bromide (CTAB) was used as a template agent. Phase composition and microstructure of the products were characterized via X-ray diffractometer (XRD) , scanning electron microscope (SEM) and transmission electron microscopy (TEM). The results show that the morphologies of HA nanorods can be controllably fine-tuning by changing the reaction temperature and time. Hexagonal single crystal HA nanorods single structure can be obtained at 120 degrees C for hydrothermal 12 h, its length is about 0. 5-1. 0 mu m, diameter is about 15-30 nm. Finally, the role of CTAB was studied by the formation process of nanorods crystalline structure in details, and verified by experiment.

Plate-like and nanoparticle barium titanate (BaTiO3 [BT]) films are synthesized on Ti substrate by low temperature reaction using Ti, Ba(AC)(2), and NaOH as raw materials. The films are characterized by XRD, SEM, TEM, and photoluminescence spectroscopy (PL) to obtain sizes, crystal structure, and emission peaks. The results show that BaTiO3 plate-like films can be obtained at 140 degrees C for 4h have a stronger (110) diffraction peak than other conditions. The diameter is 2.08.0 mu m. BaTiO3 nanoparticle films are obtained via changing the reaction order and the average diameter is 30 nm. The adhesion strength of BaTiO3 plate-like film is 16.9 MPa and that of the nanoparticle film is 13.6 MPa. It is shown in PL results that the emission peaks of plate-like films are from 663 to 691 nm. Finally, a solubility-crystallization mechanism and an in situ crystallization mechanism are proposed to explain the formation process of BaTiO3 plate-like films and nanoparticle films, respectively.

Barium titanate/hydroxyapatite (BaTiO3/HA) rod-like nanocomposites were fabricated by hydrothermal process at 140-180 degrees C for 12 h using the rod-like HA as a growth template, and BT precursor solution as a liquid phase. The structure was BaTiO3 nanoparticles (average diameter of 6 nm) grown on the surface of HA rod like structure (diameter of 70 nm). The piezoelectric coefficient d(33) value of the material was 1.54 pC/N, being close to the body dry bones of 0.7 pC/N. The results of periodic DFT calculations and optimized geometry of CTAB and C6H8O7 molecule obtained at the B3LYP/6-311 + g(d,p) level of theory in a suite of Gaussian 09 programs indicated CTAB and C6H8O7 molecule were key to the formation of rod-like nanocomposites. Meanwhile, a solubility - crystallization mechanism was proposed to account for the nanocomposites.

Bowl-like BaTiO3 nanoparticles were synthesized via a simple one-step hydrothermal synthesis process. The morphology and structure of the synthesized bowl-like structures were characterized by X-ray diffraction, scanning electron microscope, transmission electron microscope, and Fourier transform infrared spectroscopy. The results show that the typical diameter of bowl-like BaTiO3 is 100 nm, which presented cubic structure formed by a self-assembly nanocrystals with diameter of 31 nm. In addition, the obtained BaTiO3 nanoparticles were used as catalysts to photodegrade rhodamine B.

It was proposed that the piezoelectric effect played an important physiological role in bone growth, remodeling and fracture healing. Barium titanate/hydroxyapatite (BT/HA) nanorods piezoelectric composite was fabricated by hydrothermal process using 30 nm HA dissolved in different solvents (H2O, DMF, ethanol and ethylene glycol), and then reacted in the BaCl2, C6H8O7, butyl titanate mixture solution, respectively. The samples were characterized by XRD, IR, SEM and TEM to obtain sizes and crystal structure. The results showed that the BT/HA rod-like particles can be obtained at ethanol solvent, and the average diameter is about 30 nm and length is 150 nm. Meanwhile, BT/HA nanorod composites obtained at different solvents exhibited both good dielectric constant epsilon (18.45, 21.79, 27.40, 19.87), and piezoelectric coefficient d(33) (2.74, 3.23, 6.88, 4.20), which were all higher than the piezoelectric coefficient of natural bone. The epsilon and d(33) were improved by increasing the BT in ethanol solvent. (C) 2016 Elsevier B.V. All rights reserved.