Mechanical Properties of Aluminosilicate Nanotubes and Its Application on Desalination
Date Issued
2016
Date
2016
Author(s)
Liou, Kai-Hsin
Abstract
We investigated the mechanical properties of single-walled aluminosilicate nanotubes (AlSiNTs) using a multiscale computational method and then conducted a comparison with single-walled carbon nanotubes (SWCNTs). By comparing the potential energy estimated from molecular and macroscopic material mechanics, we were able to model the chemical bonds as beam elements for the nanoscale continuum modeling. The proposed approach also enabled the creation of hypothetical nanotubes to elucidate the relative contributions of bond strength and nanotube structural topology to overall nanotube mechanical strength. Our results indicated that it is the structural topology rather than bond strength that dominates the mechanical properties of the nanotubes. Finally, we investigated the relationship between the structural topology and the mechanical properties by analyzing the von Mises stress distribution in the nanotubes. Most existing theoretical studies on the mechanical properties of AlSiNTs are based on defect-free models, despite the fact that experiment results have revealed a variety of defects in AlSiNTs. Herein we developed a method for the modeling of defective AlSiNTs to enable the quantitative investigation of relationships among defect structures, structural stability, and mechanical properties of AlSiNTs. The defect structures dealt with in the proposed models are based on experimental findings. Our assessment of the stability and mechanical strength of nanotubes is based on multiscale computational tools, including density functional theory, molecular modeling, and nanoscale continuum modeling. Our study also identified the defect structure with the most pronounced impact on the stability and mechanical properties of AlSiNTs. In the last part of the study, we investigated the performance and applicability of aluminosilicate nanotube membrane, including water permeability and salt rejection for AlSiNTs with various sizes.
Subjects
Nanoscale continuum modeling
Elastic modulus
Defective model
Computational chemistry
Type
thesis
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