Modeling and Investigation of Interfacial Interaction between PLA and One Type of Deficient Hydroxyapatite
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- 作者：Tao Guo ; Shaobing Zhou ; Xiaotong Zheng ; Jing Jiang
- 刊名：Journal of Physical Chemistry A
- 出版年：2009
- 出版时间：June 25, 2009
- 年：2009
- 卷：113
- 期：25
- 页码：7112-7123
- 全文大小：601K
- 年卷期：v.113,no.25(June 25, 2009)
- ISSN：1520-5215
文摘
A model of one type of deficient hydroxyapatite (D-HA) was constructed, and the interaction mechanism between polylactide acid (PLA) and the (001) surface of D-HA was also investigated for the first time employing density functional theory (DFT) in the Perdew, Burke, and Ernzerhof (PBE) generalized gradient approximation (GGA). First, a mathematical model of D-HA was abstracted from experimental facts, through which a group of special values and the nonstoichiometric formula, Ca8[(HPO4)3(PO4)2(CO3)](OH)2, were obtained. Next, a stable configuration of D-HA was achieved with the method of searching stable structure gradually. After the most stable configuration was identified, our attention mainly turns to the results concerning the (001) surface of D-HA. Methyl lactate was employed to act as PLA monomer estimating the interaction behavior between PLA and D-HA. Simultaneously, to achieve an accurate description of hydrogen bonds (hbs), a plane wave energy cutoff of 700 eV was used. Significantly, we observed that there were two P−OHs on the surface, but only one can form a hydrogen bond with PLA; also, besides the interaction between carbonyl oxygen (C═O) in the PLA and calcium ions in the D-HA, there are two kinds of hbs interactions: one type is the medium stronger hbs between the C═O and the hydrogen in HPO42− with the bond length of 1.69 Å and bond energy of about 48 kJ mol−1; the other is the weak hbs between the oxygen in phosphate and the hydrogen in methyl/methylene with the average bond length of about 2.48 Å and bond energy of about 9 kJ mol−1. PDOS was also employed to characterize the existence of hbs. Our results may have potential promotion to investigate the properties of polymeric nanocomposites.