Metal-Assisted Injection Spinning of Ultra Strong Fibers from Megamolecular LC Polysaccharides

Area of Science:

• Materials Science
• Polymer Chemistry
• Biotechnology

Background:

• Liquid crystalline (LC) hydrogels exhibit tunable functionalities and mechanical properties.
• Sacran, a supergiant polysaccharide from Aphanothece sacrum, possesses abundant anionic groups (sulfates, carboxylates).

Purpose of the Study:

• To develop ultra-strong sacran hydrogels and fibers.
• To investigate the effect of metal ion cross-linking on molecular orientation and mechanical strength.

Main Methods:

• Sacran hydrogels and fibers were produced via cross-linking with trivalent metal ions (Al³⁺, Cr³⁺, Fe³⁺, In³⁺, Er³⁺, Sr³⁺) under injection flow.
• Crossed-polarizing microscopy and X-ray diffraction imaging were used to analyze molecular orientation.

Main Results:

• The cross-linking process induced a uniaxial molecular orientation within the LC gel fibers.
• The oriented sacran hydrogels and fibers demonstrated outstanding mechanical characteristics.

Conclusions:

• Metal ion-induced molecular orientation is a key strategy for enhancing the mechanical strength of sacran hydrogels.
• Sacran-based materials show significant potential for applications requiring high mechanical performance.