查看文章

Polyfluorene nanotubes are synthesized by solution assisted wetting of porous anodic alumina membranes. Well aligned arrays of close packed (∼10⁹ tubes/cm⁻²) discrete nanotubes are obtained. Individual tubes have diameters of ∼260 nm and wall thicknesses of ∼50 nm. X-ray diffraction measurements carried out on nanotube arrays embedded in host templates indicate a polymer chain alignment along the long axes of the template pores and, as a result, along the long axes of the nanotubes themselves. Optical spectroscopic studies of mats of nanotubes on glass substrates yield well resolved emission spectra reflecting a narrowed distribution of emitting chain segments with increased effective conjugation lengths. The data indicate intrachain reorientation of the amorphous random poly(9,9-dioctylfluorene-2,7-diyl) molecular conformation to the more planar (low energy) extended 2₁ helical β-phase …