Controlling Microstructure-Transport Interplay in Highly Phase-Separated Perfluorosulfonated Aromatic Multiblock...

Area of Science:

• Polymer Science
• Materials Science
• Electrochemistry

Background:

• Proton-conducting polymer electrolyte membranes (PEMs) are crucial for fuel cells.
• Achieving optimal nanoscale morphology and ion transport remains a challenge.
• Multiblock polysulfones offer tunable properties for PEM applications.

Purpose of the Study:

• To design and synthesize proton-conducting multiblock polysulfones with controlled nanoscale phase-separation.
• To investigate the relationship between morphology, interfaces, and transport properties.
• To optimize material architecture for enhanced polymer electrolyte membrane performance.

Main Methods:

• Synthesis of multiblock polysulfones with perfluorosulfonic acid side chains.
• Characterization of microstructures using small-angle neutron scattering (SANS) across various hydration levels.
• Analysis of swelling behaviors and correlation with transport properties.

Main Results:

• Superacid side chains induced highly ordered morphologies tunable via ion-exchange capacity and block lengths.
• Observed peculiar swelling behaviors at two scales attributed to polymer particle dilution.
• Established a direct correlation between interface quality, ionic nanodomain connectivity, and proton conductivity.
• Proton conductivity showed a linear dependence on the microscopic expansion of ionic and block domains.

Conclusions:

• Tailored nanoscale phase-separation and block-induced connectivity are key for optimizing ionomers.
• Controlled aromatic ionomer architectures can significantly improve polymer electrolyte membrane performance.
• The study provides insights into designing next-generation materials for efficient proton conduction.