Liquid–crystalline properties of aqueous suspensions of natural clay nanosheets

@article{Paineau2013LiquidcrystallinePO,
  title={Liquid–crystalline properties of aqueous suspensions of natural clay nanosheets},
  author={Erwan Paineau and Adrian Marie Philippe and K. Antonova and Isabelle Bihannic and Patrick Davidson and Ivan Dozov and Jean-Christophe P. Gabriel and Marianne Imp{\'e}ror-Clerc and Pierre Levitz and Florian Meneau and Laurent J. Michot},
  journal={Liquid Crystals Reviews},
  year={2013},
  volume={1},
  pages={110 - 126}
}
Clay minerals, like beidellite or nontronite, spontaneously exfoliate in water and form colloidal suspensions of nanosheets. In a given range of concentration, these suspensions display a nematic liquid–crystalline phase whose structure and properties can be conveniently studied in detail by polarized-light microscopy and small-angle X-ray scattering (SAXS). Moreover, in situ SAXS investigations of sheared clay suspensions provide information about their flow properties, both in the isotropic… 
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References

SHOWING 1-10 OF 110 REFERENCES
Liquid–crystalline aqueous clay suspensions
TLDR
Small-angle x-ray scattering measurements of gel samples reveal strong positional and orientational orders of the particles, proving unambiguously the nematic character of the gel and, thus, clearly refuting the still prevalent “house of cards” model.
The isotropic-nematic interface in suspensions of Na-fluorohectorite synthetic clay.
TLDR
The experiments indicate that the platelets align homeotropically both at the isotropic sol-nematic sol interface and at the nematic sol-wall interface, and the complex alignment effect of a horizontally applied magnetic field in the nematics sol is investigated.
Liquid-crystalline nematic phase in aqueous suspensions of a disk-shaped natural beidellite clay.
After size-selection and osmotic pressure measurements at fixed ionic strength, the behavior of aqueous colloidal suspensions of anisotropic disklike beidellite clay particles has been investigated
Observation of Nematic Liquid-Crystal Textures in Aqueous Gels of Smectite Clays
Aqueous suspensions of two smectite clays, natural bentonite and synthetic laponite B, were prepared at concentrations ranging from 0.01 to 0.1 g/cm3. Viewed at rest between crossed polarizers,
Isotropic-nematic phase transition of nonaqueous suspensions of natural clay rods.
TLDR
An isotropic-nematic- nematic phase equilibrium was seen to develop in phase separated samples after 1 month standing and is ascribed to the effect of polydispersity and possibly gravity.
Nematic textures in colloidal dispersions of Na-fluorohectorite synthetic clay.
TLDR
It is suggested that discrepancies could be due to the high polydispersity and the irregular shape of the authors' Na-fluorohectorite particles, as well as diffusive double-layer effects, which could result in a competition between nematic ordering and gelation.
Orientational order in gravity dispersed clay colloids: a synchrotron x-ray scattering study of Na fluorohectorite suspensions.
TLDR
This work presents synchrotron x-ray diffraction from gravity dispersed solutions of Na fluorohectorite, a synthetic swelling clay, over a large NaCl concentration range and identifies two distinct gel regions characterized by differences in orientational anisotropy and domain size.
Swollen liquid-crystalline lamellar phase based on extended solid-like sheets
TLDR
A lyotropic liquid-crystalline lamellar phase comprising an aqueous dispersion of planar solid-like sheets in which all the atoms involved in a layer are covalently bonded is described.
Sol-gel and isotropic/nematic transitions in aqueous suspensions of natural nontronite clay. Influence of particle anisotropy. 2. Gel structure and mechanical properties.
TLDR
The rich phase behavior of clay minerals, notably the fact that some clay minerals display an isotropic/nematic transition while others exhibit a sol-gel transition, requires a full understanding of all the interactions in the system that can only be achieved by working on well-characterized size-selected samples.
Liquid crystal phase transitions in suspensions of polydisperse plate-like particles
TLDR
A suspension of plate-like colloids that shows isotropic, nematic and columnar phases on increasing the particle concentration is described, finding that the columnar two-dimensional crystal persists for a polydispersity of up to 25%, with a cross-over to smectic-like ordering at very high particle concentrations.
...
1
2
3
4
5
...