Fabrication of Superstrong Ultrathin Free-Standing Single-Walled Carbon Nanotube Films via a Wet Process

A one-pot and readily practical approach is described for the preparation of superstrong, ultrathin, free-standing single-walled carbon nanotube (SWNT) films. The SWNT films, with controlled thicknesses of tens to hundreds of nanometers, are prepared from commonly commercialized SWNTs via a wet process. The SWNTs could be easily transferred onto any substrates after self-releasing from filter membranes without further treatment. The obtained films exhibit excellent performances with sheet resistance of 223 O sq-1 and a transparency of 90% at 550 nm was obtained. Most important is that the as-prepared free-standing SWNT ultrathin films showed extremely high tensile strength up to 850 MPa for only about a 20-nm thick film, which has great significance for practical applications, for example, as flexible electrode materials. The SWNT film is used to construct a capacitive touch-screen prototype, which has a highly sensitive and quick signal touch response.