Confinement of polyaniline chains in capillary layers: an ordering effect of the uniaxially aligned surfaces

An ordering effect of uniaxially aligned poly(tetrafluoroethylene) (PTFE) substrates prepared by rubbing on polyaniline (PANI) molecules at the interfaces of PTFE/PANI film and PTFE/PANI solution has been investigated using electronic absorption spectroscopy. It was observed slight dichroism in electronic spectra from only very thin (thickness ∼20 nm and less) PANI films as well as from PANI solutions of capillary thickness (10 to 30 μm) confined by oriented PTFE surfaces. The ordering effect is discussed in terms of a hydrodynamic flow arising upon sample formation and steric factors at the PTFE surface, which cause uniaxial deformation of the polymer coil on the rubbed PTFE surface.