Surface Structure and Properties of Calcium Hydroxyapatite Modified by Hexamethyldisilazane

Area of Science:

• Materials Science
• Surface Chemistry

Background:

• Synthetic calcium hydroxyapatite (CaHAP) is a widely used biomaterial.
• Understanding and modifying CaHAP surface properties is crucial for its applications.
• Carbon dioxide adsorption on CaHAP can be influenced by surface chemistry.

Purpose of the Study:

• To modify the surface of synthetic calcium hydroxyapatite (CaHAP) particles using hexamethyldisilazane (HMDS).
• To characterize the surface changes of modified CaHAP.
• To evaluate the effect of surface modification on carbon dioxide adsorption.

Main Methods:

• Repeated treatment of CaHAP with HMDS in hexane followed by thermal treatment.
• Characterization using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR).
• Assessment of carbon dioxide adsorption capacity.

Main Results:

• Modification did not alter XRD patterns or particle shape but increased particle width.
• FTIR confirmed reaction between HMDS and surface P-OH groups, forming surface Si-(CH3)3 groups.
• Modified CaHAP surfaces became hydrophobic and exhibited significantly lower CO2 adsorption.

Conclusions:

• Surface modification with HMDS effectively alters the surface chemistry of CaHAP.
• The hydrophobic nature of modified CaHAP reduces its affinity for CO2.
• This modification offers potential for controlling CaHAP interactions in various applications.