Gyroid nanostructured soft membranes formed by controlling the degree of crosslinking polymerization of bicontinuous cubic liquid-crystalline monomers

The self-organization of liquid-crystalline monomers and subsequent polymerization is a unique strategy for creating nanostructured polymer membranes with novel functions and innovative properties. In this study, we developed gyroid nanostructured soft polymer films based on this strategy. Two types of amphiphile zwitterion monomers were designed and synthesized: a single-type amphiphile zwitterion monomer (S-ZI) and a gemini-type monomer (G-ZI). These compounds show liquid-crystalline behavior in the presence of bis(trifluoromethanesulfonyl)imide (HTf2N) and water. We attempted to find an appropriate mixing ratio of S-ZI and G-ZI that satisfied the following two criteria: suitability for the exhibition of bicontinuous cubic (Cub(bi)) phases and acquisition of self-standing properties and softness. The 25/75 wt% component ratio of S-ZI/G-ZI was found to meet these conditions. By carrying out a polymerization for the mixture in the above mixing ratio in the Cub(bi) phase, a polymer film with self-standing properties and resistance to bending was successfully obtained. This film showed a high ionic conductivity of 1.27 x 10(-2) S cm(-1) under a relative humidity of 90%.

Automated summary

A novel gyroid nanostructured soft polymer film was developed based on the self-organization of liquid-crystalline monomers and subsequent polymerization. Two types of amphiphile zwitterion monomers were designed and synthesized, and a suitable mixing ratio was found to meet the criteria for exhibiting desired phases and properties. The polymer film obtained showed high ionic conductivity under specific conditions, demonstrating its potential for innovative applications.