The lyotropic liquid crystalline phases of the potassium caprate-water system have been investigated by means of a polarizing microscope.
Three typical phases of lyotropic liquid crystal were observed in the binary mixture of potassium caprate and water，as being respectively a neat phase，a viscous isotropic phase and a middle phase. The phase diagram of the potassium caprate-water system shows the same form as the other soap-water systems qualitatively， for example the potassium palmitate-water system.
The liquid crystal growth experiments for both the neat phase and the middle phase were performed by the drying method. As for the neat phase，it was confirmed that the spherulytic neat and the neat layer around the bubble are the characteristic patterns of the earlier stage of the growth. This was reported by us in the study of the monoglyceride-water system. The growth patterns of the middle phase grown from the isotropic solution differ from those of the neat phase but resemble those of the "solid" crystal.