Kang Xu (CUNY–The City College of New York, United States)
LinkedIn: @Kang Xu
Abstract: We use shallow nitrogen-vacancy (NV) centers in diamond to probe the nanoscale dynamics of interfacial water confined between diamond and a fluorinated oil layer. By selectively detecting 1H and 19F nuclei using NV-NMR, we resolve distinct diffusion behaviors of water and oil near the interface. Our results reveal that water diffuses much faster than oil and is gradually displaced over days. Molecular dynamics simulations and surface-sensitive X-ray spectroscopy support the observation of slow, thermally driven reorganization. This work highlights NV-NMR as a powerful tool for studying molecular-scale interfacial processes under ambient conditions.
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Hi Kang,
Exciting experiments and results! Regarding the H signal with a broad linewidth of 70 kHz, do you have any thoughts on how to achieve a narrower signal with better resolution? Looking forward to hearing your insights. -
Hi Yunfan,
Thanks for your comment! The 70 KHz signal is FFT result from correlation measurement protocol. Which is FID like signal resulted from diffusion out the detection zone of NV. Narrower linewidth could be down by deeper NV for micrometer scale detectio or hyperpolarize the target nuclei to overcome the thermal polarization limit. However, I don’t think these two approach would work for H signal from interfacial water. Firstly, micrometer scale detection may not gain more signal from thin interfacial water; secondly, hyperpolarize interfacial water maybe not that easy? Thanks for your comment agian!
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Hi Kang,
Nice presentation! One thing I am confused about is, why do 19F and 1H have these differing behaviors around the diamond? Is it only because 19F is more “slow” or are there other factors involved?-
Hi Raj,
Thanks for your comment! I think “slow” should be the main factor of there diffusion behavior. But the two dimensional nature of 2D of 1H and 3D nature of 19F may also cause some difference, althrough we did not go very detail about this difference. There is a paper considering this model as a difference. “Power-law scaling of correlations in statistically polarised nano-NMR”. Have a nice weekend!
Best
Kang
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