Experimental identification of diffusive coupling using 2D NMR

Area of Science:

• Materials Science
• Physical Chemistry
• Analytical Chemistry

Background:

• Nuclear Magnetic Resonance (NMR) is widely used for pore size distribution analysis.
• Traditional NMR methods assume fast diffusion within pores and neglect inter-pore diffusion.
• These assumptions are often violated in complex materials, complicating relaxation time analysis.

Purpose of the Study:

• To develop a new 2D NMR technique to overcome limitations of existing methods.
• To identify and analyze diffusive coupling between pores in complex materials.
• To provide a more accurate interpretation of pore structure.

Main Methods:

• A novel 2D NMR technique was developed.
• Associated data analysis was created to work directly with time-dependent experimental data.
• Laplace inversion was avoided to directly identify diffusive coupling signatures.

Main Results:

• The new technique successfully identified the signature of diffusive coupling between pores.
• Measurements on microporous glass beads demonstrated the technique's efficacy.
• Numerical simulations corroborated the experimental findings.

Conclusions:

• The presented 2D NMR method offers a more robust approach to pore size distribution analysis in complex materials.
• It allows for the direct observation of diffusive coupling, improving interpretation accuracy.
• This technique enhances the understanding of pore network dynamics.