To obtain high quality of drinking water free from biocontaminants is especially important issue. A new strategy employing smectic liquid‐crystalline ionic membranes exhibiting 2D structures of layered nanochannels for water treatment is proposed for efficient virus removal and sufficient water flux. The smectic A (SmA) liquid‐crystalline membranes obtained by in situ polymerization of an ionic mesogenic monomer are examined for removal of three distinct viruses with small size: Qβ bacteriophage, MS2 bacteriophage, and Aichi virus. The semi‐bilayer structure of the SmA significantly obstructs the virus penetration with an average log reduction value of 7.3 log10 or the equivalent of reducing 18 million viruses down to 1. Furthermore, the layered nanochannels of the SmA liquid crystal allow efficient water permeation compared to other types of liquid‐crystalline membrane consisting of nanopores.

Here we report columnar liquid-crystalline (LC) nanostructured membranes that highly remove viruses and show sufficient water permeation. These membranes were prepared by employing two-component liquid crystals that exhibit tetragonal columnar phases. The membranes exhibited virus rejection values of >99.99% (log10 reduction value (LRV) > 4) and water flux ranging from 19 to 61 L m–2 h–1 (operation pressure: 0.3 MPa). These membranes were fabricated by photopolymerization of a fan-shaped diol molecule and imidazolium ionic liquid mixture, followed by subsequent removal of the ionic liquid. The rejection values and water flux depend on the fraction of ionic liquid. These results show new design strategies of materials for the water treatment nanostructured membranes that remove pathogens and contaminants.

We have developed a two-dimensional (2D) liquidcrystalline (LC) nanostructured water-treatment membrane showing high virus rejection ability (over 99.99997% for bacteriophage Qβ) and improved water permeation. Polymerizable gemini amphiphiles have been designed and synthesized. They have H-shaped gemini-type structures of thermotropic smectic liquid crystals composed of cationic imidazolium moieties. One of the gemini amphiphiles shows a smectic A phase with an interdigitated bilayer structure. A cross-linked self-standing 2D nanostructured polymer film has been obtained by in situ photopolymerization of the gemini amphiphile in the smectic phase. The length of linkers in gemini amphiphiles affects the formation of LC phases. The 2D nanostructured membrane also showed selective salt rejection.

Ion-conductive liquid-crystalline molecules with high-oxidation resistance, which were designed with density functional theory calculation, improved charge–discharge reactions in Li-ion batteries.

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