Table 2.
Elastic moduli and lattice parameters for pure hydroxylapatite and for 6 and 13.4 wt% carbonated hydroxylapatite computed using both MD and DFT. The elastic constants (Cij), the bulk modulus (B), and the elastic modulus (E) are expressed in GPa; the lattice parameters (a, b, c) are in Å, and the surface energies (γ) are in J/m2. Experimental data from [50, 61, 62].
| 0 wt% CO3 | 6 wt% CO3 | 13.4 wt% CO3 | |||||
|---|---|---|---|---|---|---|---|
| MD | DFT | Experimental | MD | DFT | MD | DFT | |
| Elastic Constants (GPa) | |||||||
| C11 | 137.4±0.3 | 118.58 | 137 | 126.6±1.5 | 117.63 | 114.0±2.5 | 118.21 |
| C22 | 138.2±0.9 | – | – | 124.5±2.6 | – | 117.0±1.5 | – |
| C33 | 185.4±0.3 | 166.38 | 172 | 140.0±3.4 | 148.18 | 106.1 ±1.7 | 128.02 |
| C12 | 49.4±0.3 | 32.27 | 43 | 52.2±1.2 | 49.28 | 48.0±1.7 | 29.95 |
| C13 | 70.5±0.1 | 65.73 | 55 | 53.6±1.7 | 47.39 | 45.0±1.1 | 45.35 |
| C23 | 70.7±0.3 | – | – | 52.8±2.2 | – | 43.6±1.0 | – |
| C44 | 52.1 ±0.1 | 40.4 | – | 37.1 ±1.9 | 28.49 | 30.6±0.9 | 24.26 |
| C55 | 51.4±0.1 | – | – | 37.5±1.8 | – | 30.0±0.9 | – |
| C66 | 44.3±0.1 | – | – | 35.4±1.4 | – | 33.0±0.7 | – |
| Moduli (GPa) | |||||||
| B | 91.7±0.2 | 77.9 | 89 | 78.5±1.4 | 74.3 | 67.5±2.6 | 67 |
| E | 120.9±0.1 | 103.2 | 114 | 96.8±2.1 | 87.7 | 82.8±3.8 | 86.2 |
| Lattice Parameters (A) | |||||||
| a | 9.36±0.00 | 9.56 | 9.42 | 9.29±0.08 | 9.5 | 9.24±0.11 | 9.48 |
| b | 16.19±0.00 | 16.56 | 16.31 | 16.09±0.01 | 16.43 | 15.92±0.11 | 16.33 |
| c | 6.87±0.00 | 6.89 | 6.88 | 6.9±0.04 | 6.93 | 6.93±0.11 | 6.91 |
| Surface Energy (J/m2) | |||||||
| γ001 | 1.04±0.00 | – | – | 0.75±0.04 | – | 0.54±0.03 | – |