Maintaining hexagonal structures through interfacial positioning of crosslinkers for nanofiltration

Area of Science:

• Materials Science
• Polymer Chemistry
• Nanotechnology

Background:

• Lyotropic liquid crystals (HLLC) offer potential for advanced membrane fabrication.
• Controlling structure during polymerization is crucial for membrane performance.
• Interfacial crosslinker positioning is key to maintaining HLLC structure.

Purpose of the Study:

• To investigate the effect of crosslinker positioning on HLLC structure during polymerization.
• To optimize crosslinker molecular design for enhanced membrane properties.
• To correlate HLLC structure with water filtration performance.

Main Methods:

• Systematic investigation of poly (ethylene glycol) diacrylate (PEGDA) positioning using solid-state NMR (2H and 13C) and small-angle X-ray scattering (SAXS).
• Analysis of structural changes and water filtration using grazing incidence SAXS (GISAXS) and crossflow filtration.
• Evaluation of different crosslinker molecular chain lengths.

Main Results:

• Optimal PEGDA content and distribution effectively retain the hexagonal structure.
• Longer crosslinker chains enhance cylinder connection and hexagonal structure stability.
• Well-retained HLLC structures yield defect-free membranes with improved permeability and ion rejection.

Conclusions:

• Precise control over crosslinker interfacial positioning is achievable through molecular design.
• This control enables the fabrication of highly effective nanofiltration membranes.
• Optimized HLLC systems provide superior water filtration performance.