Intermolecular double-quantum NMR techniques to probe microstructures on porous media

Area of Science:

• Magnetic Resonance Imaging
• Porous Media Characterization
• Physical Chemistry

Background:

• Intermolecular double-quantum (DQ) signals in heterogeneous systems are sensitive to sample microstructure.
• The amplitude of the DQ signal is influenced by sample heterogeneity over a characteristic correlation distance (dc).

Purpose of the Study:

• To investigate the impact of microstructural variations in porous media on DQ signals using different CRAZED-type sequences.
• To determine if specific DQ signal weightings can enhance the observation of microstructural effects.

Main Methods:

• Application of two distinct CRAZED-type pulse sequences to a porous medium phantom.
• One sequence generated a DQ-T2 weighted signal, while the other produced a DQ-T2* weighted signal.
• Analysis of how tuning the correlation distance (dc) affects the DQ signal amplitude.

Main Results:

• Experimental results demonstrated that the correlation distance (dc) can indeed alter the DQ signal in porous media.
• This alteration is dependent on the specific microstructure of the porous medium.
• The observed microstructural dependence was only evident with the CRAZED-type sequence yielding a DQ-T2* weighted signal.

Conclusions:

• The DQ-T2* weighted CRAZED-type sequence is effective in probing microstructural details in porous media.
• Tuning the correlation distance provides a means to non-invasively assess porous medium heterogeneity.
• This method offers potential for advanced characterization of complex materials.