On the Proton Conduction Pathways in Polyelectrolyte Membranes Based on Syndiotactic-Polystyrene.

Area of Science:

• Materials Science
• Polymer Chemistry
• Electrochemistry

Background:

• Semi-crystalline syndiotactic-polystyrene (sPS) becomes hydrophilic and proton conductive after solid-state sulfonation.
• Doping sulfonated sPS with fullerenes enhances resistance to oxidative decomposition.
• Previous studies characterized morphology and structural changes in hydrated sulfonated sPS-fullerene membranes.

Purpose of the Study:

• To investigate the relationship between hydrated domain morphology and proton conductivity in sulfonated sPS-fullerene composite membranes.
• To elucidate the influence of temperature and relative humidity (RH) on these properties.
• To provide a deeper understanding of hydration and conductivity pathways.

Main Methods:

• Solid-state sulfonation of syndiotactic-polystyrene (sPS).
• Doping with fullerenes.
• Small-angle neutron scattering (SANS) for morphological analysis.
• Proton conductivity measurements under varying temperature and RH conditions.

Main Results:

• Established a direct correlation between the morphology of hydrated domains (from SANS) and proton conductivity.
• Demonstrated the formation and evolution of hydrated domains in functionalized sPS membranes.
• Provided insights into how temperature and RH affect membrane hydration and conductivity.

Conclusions:

• The morphology of hydrated domains significantly impacts proton conductivity in sulfonated sPS-fullerene membranes.
• Understanding these morphological-conductivity relationships is crucial for optimizing proton exchange membrane applications.
• This work enhances knowledge of hydration and transport mechanisms in functionalized polymer membranes.