Dynamics of a Lyotropic Cubic Phase

Marianne Clerc , Yolande Hendrikx , Bela Farago

We study the cubic phase made of the non-ionic surfactant C12(EO)6 in presence of water. The 3D periodic structure of this phase is characterized by the space group Ia3d. This structure corresponds to a centred cubic phase where the surfactant molecules build two identical 3D periodic interwoven labyrinths separated from each other by a continuous water medium. We present recent results obtained at I.L.L. on the Spin Echo spectrometer IN 11. Our experiments show for the first time, the dynamical character of the fluctuations observed in the investigated cubic phase. Therefore measurement have been performed on a single crystal (~ 0.1 cm3) . The time dependent diffusion function $S({\bf q},t)$ has been measured for different scattering vectors q. For q vectors which do not correspond to Bragg peaks, the neutrons are scattered according to a quasi-elastic process and the associated $S({\bf q},t)$ function decreases with a characteristic time of about 20 ns. The dynamical fluctuations are most probably related to collective deformation modes of the labyrinths.

Domaines: Articles anciens

Marianne Clerc, Yolande Hendrikx, Bela Farago. Dynamics of a Lyotropic Cubic Phase. Journal de Physique II, 1997, 7 (9), pp.1205-1214. ⟨10.1051/jp2:1997181⟩. ⟨jpa-00248507⟩