Swollen liquid-crystalline lamellar phase based on extended solid-like sheets

Ordering particles at the nanometre length scale is a challenging and activ e research area in materials science. Several approaches have so far been d eveloped, ranging from the manipulation of individual particles(1,2) to the exploitation of self-assembly in colloids(3). Nanometre-scale ordering is well known to appear spontaneously when anisotropic organic moieties form l iquid-crystalline phases; this behaviour is also observed for anisotropic m ineral nanoparticles(4,5) resulting in the formation of nematic(4-7), smect ic(8) and hexagonal(9,10) mesophases. Here we describe a lyotropic liquid-c rystalline lamellar phase comprising an aqueous dispersion of planar solid- like sheets in which all the atoms involved in a layer are covalently bonde d. The spacing of these phosphatoantimonate single layers can be increased 100-fold, resulting in one-dimensional structures whose periodicity can be tuned from 1.5 to 225 nanometres. These highly organized materials can be m echanically or magnetically aligned over large pH and temperature ranges, a nd this property can be used to measure residual dipolar couplings for the structure determination of biomolecules by liquid-state NMR. We also expect that our approach will result in the discovery of other classes of mineral lyotropic lamellar phases.