Anisotropic water diffusion in nematic self-assemblies of clay nanoplatelets suspended in water

作者：de Azevedo E N; Engel**erg M^*; Fossum J O; de Souza R E

来源：Langmuir, 2007, 23(9): 5100-5105.

DOI：10.1021/la0632629

Diffusion-weighted magnetic resonance imaging provides a vivid description of the little understood role played by interfacial interactions with macroscopic bodies in the cooperative self-assembly of clay nanoplatelets suspended in water. The interfacial interaction between hydrophilic glass walls and clay platelets in a Na-fluorhectorite gel can produce, for dilute gels, a face-to-wall anchoring of the platelets that leads to a uniaxial nematic order with platelet faces parallel to the walls but with randomly distributed normals of the faces. The application of a magnetic field perpendicular to the walls transforms this uniaxial order to an extended biaxial nematic order with orthogonal alignment between normals and the field. Moreover, for apolar walls, this face-to-wall anchoring is considerably hindered, and the uniaxial nematic order can be substantially disrupted.

• 出版日期2007-4-24