Dynamics in dialysis process for liquid crystalline gel formation

Area of Science:

• Materials Science
• Polymer Chemistry
• Biophysics

Background:

• Curdlan is a microbial polysaccharide known for its gelling properties.
• Understanding the formation of ordered structures in polysaccharide gels is crucial for material applications.

Purpose of the Study:

• To investigate the simultaneous gelation and liquid crystalline formation in Curdlan solutions during dialysis.
• To elucidate the role of calcium ions and pH in the formation and ordering of liquid crystalline gels (LCG).

Main Methods:

• Observation of gelation and liquid crystalline formation using crossed nicols.
• Monitoring calcium concentration and pH during dialysis.
• Development of a theoretical model based on calcium ion diffusion.
• Analysis of scaling behavior with respect to dialysis tube radius.

Main Results:

• Gelation and liquid crystalline formation occur concurrently, forming liquid crystalline gel (LCG).
• Birefringence of LCG increases post-gelation, indicating further molecular ordering.
• Experimental and theoretical results align until amorphous gel ring formation.
• A master curve and scaling behavior were observed for LCG layer thickness.

Conclusions:

• Curdlan LCG formation involves two steps: calcium diffusion-induced ordering and cross-linking, followed by local relaxation for enhanced ordering.
• The process exhibits scaling behavior dependent on dialysis tube radius.
• The findings provide insights into the self-assembly and ordering mechanisms of Curdlan molecules.