Using Multi-Scale Scattering and Rheology to Study the Change of Solution Properties of Aqueous Solutions of Aluminosilicate Nanotubes at Different Concentrations and pH Values

• Main Authors: CHANG, CHIA-LING, 張嘉凌
• Other Authors: HUA, CHI-CHUNG
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/8z4rc3

碩士 === 國立中正大學 === 化學工程研究所 === 106 === The properties of aluminosilicate nanotube (AlSiNT) aqueous solutions at different concentrations and pH values were investigated using dynamic/depolarized dynamic light scattering (DLS/DDLS), small/wide angle X-ray scattering (SAXS/WAXS), small angle light scattering (SALS), rheology and scanning transmission electron microscope (STEM) analyses. The structural features of AlSiNT solutions can be obtained from the scattering experiments, including the aggregate size, shape, and its structural compactness. At concentrations above 1 wt%, the charges of Al-OH groups on the outer surface of the AlSiNT help produce regularly arranged tube bundles in solution which in turn constitute a 3.5 μm aggregate cluster. With decreased pH value, the hexagonal nanotube arrangement eventually disappears with altering surface charge density, and the aggregate cluster became isolated form. At pH=1.8, the 1 wt% solution was found to produce isolated‒rod dispersions. At pH=1.5, the 1 wt% AlSiNT solution exhibited a transition from solution to gel state. Using rheoloical measurements to monitor the variation of viscoelastic properties of the 1 wt% AlSiNT solution during the sol-gel transition, it was observed that G" > G' in the solution state and G" < G' when the solution turns into gel. The above features have also been revealed by scanning transmission electron microscope characterizations.