The molecular orientation of liquid crystalline (LC) hydrogels has the potential to induce a range of functionalities that can deliver great mechanical strength. Sacran is a supergiant LC polysaccharide isolated from the cyanobacterium Aphanothece sacrum with a high amount of anionic functional groups such as sulfates and carboxylates. In this article, ultra-strong sacran hydrogels and their dried fibers were produced by cross-linking under injection flow with trivalent metal ions such as Al3+, Cr3+, Fe3+, In3+, and rare-earth metal ions such Er3+ and Sr3+. Crossed-polarizing microscopy and X-ray diffraction imaging revealed a uniaxial molecular orientation in the LC gel fiber, resulting in outstanding mechanical characteristics.
Keywords: cross-linking; fibers; metal ion; polysaccharide; sacran.