Template synthesis of water-dispersible carbon nano "test tubes" without any post-treatment

Water-dispersible and uniform tubular nanocarbons with a diameter of about 10 nm were synthesized by the template method without any additional treatment after the synthesis. Since one end of each tubular nanocarbon is always open but another end is closed, the nanocarbons look like a "test tube". It was found that the present test tubes with a length not exceeding 5 μm were dispersible in water, but the 20 μm long tubes were precipitated. The origin of such water dispersibility was investigated by the detailed analyses of their structure and the dispersion state in water. It was concluded that the observed dispersibility was caused by the presence of an electric double layer around the wall of each nano test tube in water.