|M.Sc Student||Horev Yehu|
|Subject||Quantitative Analysis of Carbon Nanotube Dispersion by|
Small-Angle X-Ray Scattering
|Department||Department of Chemical Engineering||Supervisor||Professor Yachin Cohen|
|Full Thesis text|
Worldwide interest in carbon nanotubes (CNTs) is due to its unique mechanical, electrical and optical properties, which are implemented in a wide range of current and potential applications from composite materials to sensors and medicine. The ability to separate and disperse the fabricated CNTs is still a major hindrance in many applications.
Small Angle X-Ray Scattering (SAXS) is a structural characterization method applicable to macromolecules in solution and in-homogeneities of colloidal dimensions in liquids and solids. It can help reveal the state of dispersion of CNTs within its polymeric matrix. Yet, there are still open issues regarding suitable models for analysis of scattering from CNT dispersions, so that SAXS measurements may yield quantitative evaluation.
The goal of this work is to evaluate current structural models used in quantitative analysis of the CNT dispersions by small angle scattering, and to possibly suggest a suitable new model. We consider two effects. One is the significance of nanotube end caps, which may be important due to major fracture by ultra-sonication during dispersion and due to the high electron density of possible catalysis particles at the nanotube ends. A new aspect in modeling the structure of dispersed multi-walled CNTs is consideration of the changes of the cross-section due to mechanical buckling. This done by allowing a combination of circular and elliptical shapes of the CNT cross-section. The model is evaluated with respect to experimental measurement.