Langmuir, Vol.20, No.5, 1639-1646, 2004
Relationship between optical and rheological properties of polymer-added lamellar liquid-crystalline systems
Structural changes caused by polymer additives in lamellar liquid-crystalline systems have been studied by polarized microscopy and oscillatory rheology. Four ethoxylated fatty acid surfactants and two polymer additives (poly(ethylene oxide) -poly(propylene oxide)-poly(ethylene oxide)) were used. The parameters of a recently developed theoretical model were determined from the measured data. Values of the so-called orientation modulus (G(E)) were compared to the time of pseudoisotropy (t(ISO)). Their change with the polymer content and polarity show the same tendency, which means that these essentially different parameters can be used in the same way for characterizing the elastic properties of such liquid-crystalline systems.