Nuclear acoustic resonance in fluids using piezoelectric nanoparticles

Area of Science:

• Materials Science
• Physical Chemistry
• Nuclear Magnetic Resonance Spectroscopy

Background:

• Acoustic radiation, specifically ultrasound (US), can interact with matter at a molecular level.
• Piezoelectric and ferroelectric nanoparticles possess unique properties that may influence surrounding media under external stimuli.
• Nuclear Magnetic Resonance (NMR) spectroscopy is sensitive to the local environment and dynamics of atomic nuclei.

Purpose of the Study:

• To investigate the effect of ultrasound on the NMR signal of liquids containing piezo- and ferroelectric nanoparticles.
• To determine how ultrasound influences the spin-lattice relaxation time (T1) of specific nuclei (1H and 23Na).
• To explore the relationship between nanoparticle concentration and the observed changes in NMR relaxation times.

Main Methods:

• Utilized ultrasound (US) at specific frequencies (18.26 MHz for 1H, 2 x 9.13 MHz for 23Na) applied to liquid samples.
• Incorporated lead zirconate titanate (PZT) nanoparticles of varying concentrations into the liquid samples.
• Measured spin-lattice relaxation times (T1) using an inversion recovery sequence in NMR spectroscopy.

Main Results:

• Observed an elongation of the T1 relaxation time for 1H by 1.7% at 0.05% PZT concentration.
• Observed an elongation of the T1 relaxation time for 23Na by 3% at 0.04% PZT concentration.
• Demonstrated that the observed elongation of T1 scales with the concentration of PZT nanoparticles.

Conclusions:

• Ultrasound significantly influences NMR relaxation times in liquids containing piezoelectric nanoparticles.
• The concentration of piezoelectric nanoparticles plays a crucial role in the magnitude of the ultrasound-induced NMR signal changes.
• The findings suggest a potential mechanism for ultrasound-mediated modulation of NMR signals in nanoparticle suspensions.