Instability of a Nematic Lyophase

We have observed that a ternary nematic solution from sodium decyl sulphate, decanol and heavy water separated into layers of different phases during storage. The separation was favoured when the sample had been previously heated above room temperature up to 50°C. The time needed for the demixing to occur varied from several hours to weeks. The solution ended up as a three-phase system: lamellar at the top, nematic in the middle, and isotropic at the bottom. The initial homogeneous nematic solution was restored when the layers were stirred. The nematic solution prepared with ordinary water was far more resistant to demixing. The similarity to emulsions is discussed.