Molecular Dynamics Exploration of Ordered-to-Disordered Surface Structures of Biomimetic Hydroxyapatite Nanoparticles

Abstract

Hydroxyapatite (HAP, Ca10(PO4)6(OH)2) constitutes one of the main components in human bones and teeth. Investigations of the surface structures of HAP could help us to understand the interactions between the implant HAP-based biomaterials and their environment. We, in this work, systematically explored the surface structures of HAP based on two different force fields, Born–Mayer–Huggins (BMH) parameters and interface force fields (IFFs). Their different performances in constructing HAP ordered-to-disordered surface structures were compared and discussed. The annealed HAP (001), (010), (100), and (110) surface structures were obtained, and their thickness values of the disordered layers have been computed. The thicknesses have the same order of (001) < (010) < (100) < (110) even at different annealing temperatures by the two force fields. At the annealing temperature 1800 K, the theoretical prediction for the average disordered layer thickness values is 8.9 A (BMH) and 10.3 A (IFF), which are close to the ...