Phase diagrams of poly(dimethylsiloxane)/E7 mixtures

The phase behavior of blends of poly(dimethylsiloxane) and the eutectic mix ture of liquid crystals E7 is investigated. Experimental phase diagrams are established by polarized optical microscopy for two systems with widely di fferent polymer molecular weights. Surprisingly, we find a very slight loss of miscibility of the mixture as a result of an increase of the polymer mo lecular weight by almost an order of magnitude. This unexpected phase behav ior is in contrast with the results reported so far on other systems. (C) 2 001 Elsevier Science Ltd. All rights reserved.