MONOLAYER PROPERTIES OF A FUZZY ROD POLYMER - POLY(GAMMA-STEARYL-ALPHA, L-GLUTAMATE)

Static and dynamic properties, and surface morphologies of monolayers at the air-water interface of a fuzzy rod polymer, poly(gamma-stearyl alpha, L-glutamate), PSLG, have been examined by the Wilhelmy plate me thod for surface pressure, electrically induced capillary wave die-act ion (ECWD), epi-fluorescence microscopy, and atomic force microscopy ( AFM). The monolayers were first formed by spreading polymer solutions at the air-water interface and allowing the solvent to evaporate to ob tain polymer films, i.e., spread monolayers. The surface mass density was varied by either successive additions of more solutions on a given surface area or step-wise compression of the surface barrier an a Lan gmuir trough. Surface pressure isotherms at 23-60 degrees C were confi rmed to be reversible and reproducible, and an abrupt change at approx imately 60 degrees C was observed, which is reported as the melting po int of crystalline stearyl side chains. By AEM, the monolayer director n by surface alignment was confirmed as perpendicular to the compress ion direction and certain islands of departure from the monolayer stat e were visualized upon transferring the monolayers horizontally to sil icon wafers. Macroscopic anisotropy in the surface alignment was probe d by the electrocapillary waves propagated perpendicular (perpendicula r to) and parallel (//) to the director n; the surface tension anisotr opy amount to about 7% difference, sigma perpendicular to/sigma(//) < 0.07, where a is the surface tension deduced from the wave propagation characteristics. Multidomain morphologies of the monolayers were imag ed by epi-fluorescence microscopy and they were found to differ accord ing to the method of monolayer mass density variation, i.e., the succe ssive addition and step-wise compression. (C) 1996 John Wiley & Sons, Inc.