Microwave-assisted synthesis of mesoporous nano-hydroxyapatite using surfactant templates

Abstract

Mesoporous nano-hydroxyapatite (mn-HAP) was expeditiously synthesized using a pseudo sol–gel microwave-assisted protocol in the presence of two novel templates, namely sodium lauryl ether sulfate (SLES) and linear alkylbenzenesulfonate (LABS). The cooperative self-assembly of the calcium precursor with the surfactant molecules, followed by the interaction with the PO₄³⁻ ligand, led to the formation of mesoporous nano-hydroxyapatite with controlled pore sizes. The systematic use of these surfactants in combination with microwave energy input enables the precise control of pore size within a narrow-size distribution range (35 nm). The controlled growth of hydroxyapatite is confirmed using several techniques such as thermogravimetric analysis (TGA), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (XRD), low-angle X-ray diffraction, transmission electron microscopy (TEM), selected area electron diffraction (SAED), high-resolution transmission electron microscopy (HRTEM) and N₂ physisorption isotherm analysis.