Dry Spin Graphene Oxide Fibers: Mechanical/Electrical Properties and Microstructure Evolution.

Area of Science:

• Materials Science
• Polymer Science
• Nanotechnology

Background:

• Dry-spinning is an industrially favored method for fiber production due to its environmental friendliness, high yield, and lack of purification steps.
• Graphene oxide (GO) fibers are synthesized using various methods, with dry-spinning offering potential advantages over traditional wet-spinning.

Purpose of the Study:

• To synthesize graphene oxide (GO) fibers via dry-spinning of highly concentrated GO inks.
• To investigate the relationship between the micro-structure and mechanical properties of dry-spun GO fibers.
• To understand the limitations of applying polymer rheology theories to GO solutions.

Main Methods:

• Dry-spinning of graphene oxide (GO) inks with extremely high concentrations.
• Investigation of various dry-spinning conditions.
• Analysis of the micro-structure and mechanical performance of the resulting GO fibers.

Main Results:

• Dry-spinning of concentrated GO inks was successfully achieved due to suitable rheological properties.
• Larger GO liquid crystal domains did not correlate with improved mechanical properties.
• The formation of thick GO films from large domains during drying prevented intimate compaction, leading to weaker fibers compared to wet-spun GO fibers.
• Barus effects, common in polymer melt spinning, were not observed in GO solutions.

Conclusions:

• Dry-spinning of GO fibers is feasible with highly concentrated inks, offering process advantages.
• The micro-structure, specifically the evolution of GO domains during drying, critically impacts mechanical properties.
• Classical polymer rheology theories may not be directly applicable to the dynamic behavior of GO solutions.