Molecular orientation and motion of pyrene molecules at the interface of polymer LB films

The molecular orientation and the molecular motion of pyrene chromophore which is incorporated into polymer LB films were studied by UV-vis spectroscopy and fluorescence anisotropy measurement. The pyrene orientation was largely affected by the side alkyl chains of the polymers. The pyrene chromophore orients perpendicular to its layer plane in N-dodecyl acrylamide polymer (p(DDA)) LB films, while the pyrene orients parallel to its layer plane in tert-pentyl acrylamide polymer (p(tPA)) LB films. Both polymer LB films show high anisotropy values, indicating that the molecular motion of pyrene chromophore is restricted in the polymer LB films.