Modulating Silica-SWCNT Interactions for Enhanced Dispersion Stability and Hybrid Material Formation

Carbon materials possess extraordinary physical properties and hence they are of interest in microelectronics, energy storage and gas isolation. Single walled carbon nanotubes (SWCNT) form a special class of carbon materials with high electric and thermal conductivity. However as synthesized these SWCNT exist in the form of bundles primarily because of intertubular van der waals attraction. A hybrid material containing well separated SWCNT would be necessary for their cost-effectiveness higher adaptability. However, fabricating SWCNT composite materials while retaining their strength, thermal and electrical properties is a challenge. In this work we use the approach of dispersing the tubes in liquid and its subsequent drying to form highly porous hybrid materials. Recently, our group has developed a novel technique to disperse SWCNT in aqueous media using inorganic silica nanoparticles. In this work we develop a better understanding of the mechanism involved in the dispersibility and dispersion stability of SWCNT by silica nanoparticles. We characterize the dispersion using small angle x-ray scattering, Raman scattering, AFM and TEM. We find that silica nanoparticles’ curvature, concentration and surface chemistry play crucial role in determining the physical properties of the binary dispersion. In addition to the fundamental understanding of SWCNT dispersibility, we fabricate and characterize novel hybrid silica-SWCNT aerogels and xerogels as a new class of highly conductive materials. The constructed hybrid materials possess a tunable porosity (from low to high) with minimum resistivity. We believe that the fabricated material can be used as a precursor for electrode manufacturing which further can used in various electrochemical applications.