Effect of cetyltrimethylammonium bromide on morphology and porous structure of mesoporous hydroxyapatite
(1. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China;
2. Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital,
Central South University, Changsha 410008, China)
2. Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital,
Central South University, Changsha 410008, China)
Abstract: The mesoporous hydroxyapatite (HA) was synthesized by hydrothermal method utilizing cationic surfactant cetyltrimethylammonium bromide (CTAB) as template. The crystalline phase, morphology and porous structure were characterized respectively by different detecting techniques. The results reveal that the particles are highly crystalline hydroxyapatite phase. The surfactant has little influence on the morphology of the crystals, but affects the porous structure obviously. The sample without CTAB has a low surface area not exceeding 33 m2/g, and no distinct pores can be observed by TEM. While the samples obtained with the surfactant get better parameters. Numerous open-ended pores centered at 2-7 nm spread unequally on the surface of the hydroxyapatite nanorods. The N2 adsorption-desorption experiments show type IV isotherms with distinct hysteresis loops, illustrating the presence of mesoporous structure. When the mole ratio of CTAB to HA is 1:2, the sample has the largest surface area of 97.1 m2/g and pore volume of 0.466 cm3/g.
Key words: hydroxyapatite; cetyltrimethylammonium bromide; cationic surfactant; soft-template; mesoporous structure