水分子在纳米颗粒表面的扩散――来自核磁共振放松计的见解
Aleksandra Stankiewicz1, Adam Kasparek1, Elzbieta Masiewicz1
1Department of Physics and Biophysics, University of Warmia & Mazury in Olsztyn, Oczapowskiego 4, 10-719 Olsztyn, Poland.
The journal of physical chemistry. B
|January 31, 2024
概括
核磁共振 (NMR) 放松实验揭示了二维水在纳米颗粒上的扩散. 水分子表现出温度独立的表面停留时间,这对于理解纳米粒子与水的相互作用至关重要.
科学领域:
- 材料科学 材料科学 材料科学
- 物理化学 物理化学
- 纳米技术纳米技术
背景情况:
- 了解纳米粒子界面上的水的行为对于催化,药物输送和传感中的应用至关重要.
- 功能化纳米颗粒由于其可调节性质和生物相容性而被广泛使用.
研究的目的:
- 研究水分子与功能化纳米粒子相互作用的动力学.
- 量化水在纳米粒子表面的二维转化扩散和停留时间.
主要方法:
- 进行了质子自旋格子核磁共振 (NMR) 放松实验.
- 测量范围涵盖广泛的频率范围 (10 kHz至10 MHz) 和温度范围 (263 K至313 K).
- 分析重点是25nm和45nm纳米颗粒的水分散.
主要成果:
- 确定了纳米粒子表面附近的水的二维转化扩散.
- 发现表面的水居住寿命与温度无关:25nm纳米颗粒的~5×10−6s和45nm纳米颗粒的~1.5×10−5s.
- 确定了转化相关时间,显示较大的纳米粒子的温度依赖性.
结论:
- 这项研究量化了-水界面上的水扩散动态.
- 对结合和扩散水分的洞察力为我们提供了更深入地了解表面水合的理解.
- 这些发现对于设计具有受控地表水相互作用的纳米材料具有重要意义.
相关概念视频
01:17Chemical Shift: Internal References and Solvent Effects
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In an NMR sample, precise measurement of the absolute absorption frequencies of nuclei is difficult. A standard internal reference compound is added, and the frequency difference between the reference signal and sample signals is measured.
The internal reference compound generally used in NMR spectroscopy is tetramethylsilane (TMS). TMS is preferred because it is chemically inert, soluble in NMR solvents, and easily removable. Also, the highly shielded methyl protons in TMS yield an intense...
The internal reference compound generally used in NMR spectroscopy is tetramethylsilane (TMS). TMS is preferred because it is chemically inert, soluble in NMR solvents, and easily removable. Also, the highly shielded methyl protons in TMS yield an intense...
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01:15NMR Spectroscopy: Chemical Shift Overview
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The position of the absorption signal of a sample is reported relative to the position of the signal of tetramethylsilane (TMS), which is added as an internal reference while recording spectra. The difference between the absorption frequencies of the sample and TMS (in Hz) is divided by the spectrometer operating frequency (in MHz) to obtain a dimensionless quantity called the chemical shift. It is reported on the δ (delta) scale and expressed in parts per million.
For instance, the proton...
For instance, the proton...
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