Influence of the chain length of K-soaps on the phase diagram and structural parameters of nonaqueous liquid crystals and the gel phase in K-soap/glycerol binary systems

Analogously to the aqueous K-soap/water systems already examined, the five glycerol (G1)-containing systems KCn/Gl(n = 12, 14, 16, 18, 22) also built up hexagonal (H-alpha), lamellar (L-alpha) isotropic micellar (S), gel-like (G) and crystalline phases (C). These phases were identified by texture ob servations with a polarizing microscope. by differential scanning calorimet ry measurements and by X-ray diffraction investigations. The appertaining p hase regions were plotted in the binary phase diagram. Binary G1-containing K-soap systems have the following properties. The H-alpha phase is built u p at low soap concentration. The L-alpha phase is formed at high soap conce ntrations. The temperature of the phase transition H-alpha <-> S runs throu gh a maximum. Increasing the chain lengths of the soaps shifts the formatio n of the H-alpha phase to lower soap concentration. A strong correlation be tween the chain length of K-soaps and the d values of L-alpha, H-alpha, G a nd C phases is found. Based on the comparison of the X-ray diffractograms o f the G phase a structural model is proposed. The G phase consists of two g roups of domains with two different dimensions.