Chromatic materials such as polydiacetylene change color in response to a wide variety of environmental stimuli including changes in temperature, pH and chemical or mechanical stress, and have been extensively explored as sensing devices. Here is reported the facile synthesis of carbon nanotube/polydiacetylene nanocomposite fibers which rapidly and reversibly respond to electrical current, with the resulting color change being readily observable with the naked eye. These composite fibers also chromatically respond to a broad spectrum of other stimulations: for example, they exhibit rapid and reversible stress-induced chromatism with negligible elongation. Nanotube/polydiacetylene nanocomposite fibers could have various applications in sensing.
 The present invention relates to composites and more particularly relates to composites of carbon nanotubes and a polymer such as polydiacetylene. The United States government has rights in this invention pursuant to Contract No. DE-AC52-06NA25396 between the United States Department of Energy and Los Alamos National Security, LLC for the operation of Los Alamos National Laboratory.