Phase Diagram of the C12E6/D2O System Revisited: Effect of strong magnetic Fields

Lyotropic mixtures composed by heavy water and C12E6 (n-dodecylhexaoxyethylene glycol [CH3(CH2)(11)(OCH2CH2-CH2)(6)OH], with different mole ratios, W-0, have been studied in the presence of high magnetic fields. Depending on both thermal history and magnetic conditioning, a significant orientation of the samples is obtained and the phase boundaries are slightly modified with respect to the originally reported ones. The resulting H-2 spectra show the presence of two components, one iso-oriented and another one partially oriented. To quantify the amount of oriented spectral components a full simulation was performed, based on 0th, 2nd, and 4th rank Legendre polynomials. Experimental investigation is focused on the hexagonal mesophase, but information is also given on the lamellar phase. The iso-orientation of samples is kept for several months. The presence of a large amount of iso-oriented phases is confirmed by optical polarizing microscopy experiments.