Crystal structure modification of nano-hydroxyapatite using organic modifiers and hydrothermal technique

Area of Science:

• Materials Science
• Nanotechnology
• Crystallography

Background:

• Hydroxyapatite (HAp) is a crucial biomaterial with applications in bone regeneration and drug delivery.
• Controlling the crystallite size and morphology of HAp is essential for optimizing its properties.
• Hydrothermal synthesis offers a versatile route for HAp fabrication.

Purpose of the Study:

• To synthesize Hydroxyapatite (HAp) via a hydrothermal method.
• To investigate the effect of organic modifiers (urea, naphthalene, palmitic acid) on HAp crystallite size and morphology.
• To characterize the synthesized HAp using various analytical techniques and calculate structural parameters.

Main Methods:

• Hydrothermal synthesis using orthophosphoric acid and calcium hydroxide.
• Modification of HAp with organic compounds: urea, naphthalene, and palmitic acid.
• Characterization using X-ray diffraction (XRD), FTIR, FESEM, and UV-vis spectrophotometry.
• Crystallite size, strain, stress, and energy density calculations using Scherrer, Halder-Wagner, Williamson-Hall, and Sahadat-Scherrer models.
• Texture coefficient analysis and Rietveld refinement.

Main Results:

• HAp was successfully synthesized and characterized, with crystal structures within the <100 nm range.
• Organic modifiers influenced HAp crystallite size and morphology.
• Calculated strain, stress, and energy density values varied across the synthesized HAp samples.
• Texture analysis indicated specific growth planes for pure and modified HAp, with palmitic acid-HAp showing distinct plane growth.

Conclusions:

• The hydrothermal method is effective for synthesizing HAp with tunable properties.
• Organic modifiers play a significant role in controlling HAp nanostructure.
• Comprehensive analysis provides insights into the crystallographic and mechanical properties of synthesized HAp, crucial for material design.