Xu Ziwei, Zhang Li, Wang Lin, Zuo Jie, Yang Mingli
Institute of Atomic and Molecular Physics, Sichuan University Chengdu 610065 China
School of Computer Science, Sichuan University Chengdu 610065 China
RSC Adv. 2019 May 16;9(27):15298-15306. doi: 10.1039/c9ra02298h. eCollection 2019 May 14.
Nanoporous titania is one of the most commonly used biomaterials with good biocompatibility and mechanical strength. Understanding to the influence of pore structures on their performances is crucial for the design and preparation of titania-based materials. Two kinds of structural models for nanoporous titania were constructed and used to investigate the effect of pore size and/or porosity on their mechanical properties by using molecular dynamic simulations with the Matsui-Akaogi potentials. The porous structures were relaxed and their elastic constants were computed and used to evaluated their bulk, shear and Young's moduli. Overlap effect in small pores, pore size and porosity have considerable influence on computed elastic moduli. Compared to bulk rutile TiO, reduced mechanical moduli were predicted. Simulations on uniaxial tensile tests revealed an anisotropic stress-strain relationship and a brittle-to-ductile transition for structures with large porosities. Fracture failure was predicted for all the studied porous structures. The maximum stress decreases with pore size and porosity, while the corresponding strain decreases with pore size, but increases with porosity.
纳米多孔二氧化钛是最常用的生物材料之一，具有良好的生物相容性和机械强度。了解孔隙结构对其性能的影响对于二氧化钛基材料的设计和制备至关重要。构建了两种纳米多孔二氧化钛的结构模型，并通过使用具有松井-赤荻势的分子动力学模拟来研究孔径和/或孔隙率对其力学性能的影响。对多孔结构进行了弛豫处理，并计算了它们的弹性常数，用于评估其体模量、剪切模量和杨氏模量。小孔中的重叠效应、孔径和孔隙率对计算得到的弹性模量有相当大的影响。与块状金红石TiO相比，预测其力学模量降低。单轴拉伸试验模拟显示，对于具有大孔隙率的结构，应力-应变关系呈各向异性，且有从脆性到韧性的转变。预测所有研究的多孔结构都会发生断裂破坏。最大应力随孔径和孔隙率的增加而降低，而相应的应变随孔径的增加而降低，但随孔隙率的增加而增加。
