Molecular optimization of multiply-functionalized mesoporous films with ion conduction properties

Area of Science:

• Materials Science
• Nanotechnology
• Electrochemistry

Background:

• Controlling compositional and structural heterogeneity is key for optimizing ion-conduction in mesoporous materials.
• Sequential functionalization of mesoporous silica films presents challenges due to incompatible processing conditions.

Purpose of the Study:

• To develop a method for sequential processing of multiply functionalized mesoporous films.
• To correlate molecular, mesoscopic, and macroscopic properties with ion-conduction.
• To optimize synthesis and functionalization treatments for maximum proton conductivity.

Main Methods:

• Preparation of cubic mesoporous silica films.
• Sequential surface functionalization under acidic, alkaline, and nonaqueous conditions.
• Characterization using NMR spectroscopy, SAXS, TEM, elemental analysis, adsorption, and ion conductivity measurements.

Main Results:

• Stable mesoporous films with hydrophilic aluminosilica and perfluorosulfonic-acid surface groups were successfully synthesized.
• High proton conductivities (approx. 9 × 10(-2) S/cm) were achieved at elevated temperatures (120 °C).
• NMR spectroscopy revealed distinct adsorption and grafting sites for surface species within mesopore channels.

Conclusions:

• Sequential processing of incompatible steps enables the creation of compositionally and structurally heterogeneous mesoporous materials.
• Optimized functionalization and synthesis treatments are critical for maximizing proton conductivity in these advanced materials.
• The developed films show significant potential for applications requiring efficient proton transport.