Dispersion control and nematic ordering of Ni/Al layered double hydroxide suspensions

In this paper, we report the preparation of aqueous suspensions of Ni/Al layered double hydroxide (LDH) nanoparticles by a non-steady co-precipitation followed by peptization. By choosing suitable peptization temperature and time, well-dispersed suspensions were obtained. Meanwhile, the particle size, shape and size polydispersity can be efficiently controlled. Nematic ordering is observed in colloidal Ni/Al LDH suspensions and confirmed by birefringence observations and SAXS measurements. Furthermore, we showed that the sol–gel transition takes place after a liquid crystalline phase transition in concentrated Ni/Al LDH suspensions. The absence of isotropic–nematic phase separation can be attributed to the fact that the nematic phase droplets are too small to settle to the bottom of the cuvette.

Graphical abstractWell-defined Ni/Al LDH nanoparticles were prepared and nematic ordering confirmed by birefringence observations and SAXS measurements is observed in concentrated Ni/Al LDH suspensions.Figure optionsDownload full-size imageDownload as PowerPoint slide