Preparation of carbon nanotube/SiO2 composite films and their tensile properties in harsh wet environments

Abstract

The superb mechanical properties inherent with individual carbon nanotubes (CNTs) are not observed from their macroscopic assemblies such as fibers and films due to the weak interaction and thus easy sliding between CNTs, particularly when they are wetted with a liquid phase. Although various methods have been practiced to control the inter-tube sliding, all of them suffer from different deficiencies in harsh wet environments. In this study, CNT/SiO 2 composite films were prepared by chemical vapor deposition, and the embedded SiO 2 acted as an agent for gluing individual CNTs or bundles. As a result of the suppression of the inter-tube sliding, the breaking load of the composite films was not only improved by 50% over the raw CNT film but also maintained by more than 80% of its starting value in hot and wet environments such as boiled water, alcohol, HCl acid and seawater. Thanks to the superior features of the SiO 2 used for inter-tube bonding over conventional metals and polymers, this work may constitute bases for the preparation of new CNT composites and their applications in harsh environments. • The suppression of inter-tube sliding by SiO 2 led to an increase of the breaking load by about 50% over the raw CNT film. • Such cross-linking effectively controlled the inter-tube sliding even in harsh wet and hot environments. • The CNT/SiO 2 composite film had good heat resistance at temperatures up to 950 °C.