Langmuir-Blodgett films of helical rigid-rod poly(quinoxaline-2,3-diyl)s

Optically pure, helical poly(quinoxaline-2,3-diyl)s (degree of polymerization, n10-100), prepared by asymmetric living polymerization of 1,2-diisocyano-3,6-dimethyl-4,5-di(propoxymethyl)benzene with an optically pure organopalladium initiator, formed stable monolayers on a water surface. As the polymerization degree increased, more closely packed monolayers were formed, as indicated by surface pressure-area (π-A) isotherms. Up to 54 monolayers were deposited onto the solid support using the Langmuir-Blodgett (LB) technique. Polarized ultraviolet spectra of LB films showed that the helical axis was orientated parallel to the dipping direction. This optical property indicates that polymer molecules are organized anisotropically in LB films.