Polyelectrolyte-stabilized graphene oxide liquid crystals against salt, pH, and serum

Area of Science:

• Nanoscience
• Materials Science
• Colloid Chemistry

Background:

• Colloid stabilization is vital for nanoscience research and applications.
• Graphene oxide (GO) liquid crystals (LCs) are stabilized by electrostatic repulsion but are susceptible to ion screening.
• Stabilizing colloidal LCs against electrolytes remains a significant challenge.

Purpose of the Study:

• To develop an effective strategy for stabilizing graphene oxide (GO) liquid crystals (LCs) under harsh conditions.
• To investigate the use of polyelectrolyte association for enhancing LC stability in the presence of electrolytes.
• To assess the stability of modified GO LCs across a range of ionic strengths and pH values.

Main Methods:

• Association of polyelectrolytes, specifically sodium poly(styrene sulfonate) (PSS) and a polyzwitterion (PMEDSAH), onto GO sheets.
• Fabrication and characterization of GO-polyelectrolyte complexes.
• Testing the stability of GO LCs in solutions with varying NaCl concentrations (0 M to saturated), extreme pH (1 to 13), and serum.

Main Results:

• GO LCs coated with PSS or PMEDSAH demonstrated remarkable stability in the presence of high salt concentrations and extreme pH.
• The polyelectrolyte coating effectively shielded the electrostatic interactions, preventing ion screening.
• PSS- or PMEDSAH-coated chemically reduced GO (rGO) also exhibited electrolyte stability.

Conclusions:

• Polyelectrolyte association is a robust strategy for stabilizing graphene oxide (GO) liquid crystals (LCs) under challenging environmental conditions.
• This method overcomes the limitations of electrostatic stabilization in electrolyte solutions.
• The findings have implications for the practical application of GO-based materials in diverse environments.