Unique carbon nanotube architectures via surface modification and capillary effects.

摘要

The extraordinary material properties of carbon nanotubes make them an ideal candidate for a plethora of applications and many fundamental scientific studies. However, precise control over morphology of nanotube-based structures is required before their potential could be realized. A method for surface character alteration and controlled defect induction based on plasma chemistry is presented. This process induces defects in the nanotube structure by way of functionalization and the extent of disorder can be controlled by plasma time and power. This treatment has been characterized by time dependent Raman and X-ray photoelectron spectroscopy. A better understanding of the changes in the vibrational modes of nanotubes with changes in their structure could be gained from this study.; Formation of visually arresting cellular structures from aligned nanotubes by the evaporation of water was discovered. Cellular patterns arise frequently in nature on length scales ranging from microscopic to macroscopic as a result of spatially periodic and random perturbations. However, a film of aligned carbon nanotubes present an unique, yet unstudied system where pattern formation arise from the collapse and reassembly of highly ordered, anisotropic, elastic, nanoscale rods with remarkable properties.; The nanoscale dimensions of the nanotube arrays magnify the capillary forces exerted by the evaporating solvent from the interstitial spaces. Shrinkage induced crack formation in the films due to strong capillary forces of evaporating solvent and aided by strong van der Waals interactions between condensed nanotubes, result in the formation of stable cellular patterns and contiguous foams. These foams can be elastically deformed, transferred to other substrates, or floated out to produce free-standing macroscopic fabrics. The length-scale, orientation and shape of cell could be controlled by varying experimental conditions such as the length of nanotubes, rate of evaporation, and array dimensions. Pattern formation could also be tailored by prefabricating nanotube arrays by simple lithographic techniques. This study is on the fundamental understanding of capillary effects in dense arrays of ordered nanotubes and the effect of surface modification of nanotubes. This simple self-assembly process is a novel way of creating different macroscopic morphologies and architectures with nanotubes.