Department of Chemistry, University of Bayreuth, Universitätsstr.30, 95440, Bayreuth, Germany.
Diamond Light Source, Harwell Science & Innovation Campus, Didcot, Oxfordshire, OX11 0DE, UK.
Nat Commun. 2019 Mar 1;10(1):995. doi: 10.1038/s41467-019-09007-1.
Nanoparticles in solution interact with their surroundings via hydration shells. Although the structure of these shells is used to explain nanoscopic properties, experimental structural insight is still missing. Here we show how to access the hydration shell structures around colloidal nanoparticles in scattering experiments. For this, we synthesize variably functionalized magnetic iron oxide nanoparticle dispersions. Irrespective of the capping agent, we identify three distinct interatomic distances within 2.5 Å from the particle surface which belong to dissociatively and molecularly adsorbed water molecules, based on theoretical predictions. A weaker restructured hydration shell extends up to 15 Å. Our results show that the crystal structure dictates the hydration shell structure. Surprisingly, facets of 7 and 15 nm particles behave like planar surfaces. These findings bridge the large gap between spectroscopic studies on hydrogen bond networks and theoretical advances in solvation science.
溶液中的纳米粒子通过水化壳与周围环境相互作用。虽然这些壳层的结构被用来解释纳米尺度的性质，但实验结构的见解仍然缺乏。在这里，我们展示了如何在散射实验中获取胶体纳米粒子周围的水化壳结构。为此，我们合成了具有不同功能化的磁性氧化铁纳米粒子分散体。无论盖帽剂如何，我们都根据理论预测，从粒子表面识别出属于离解和分子吸附水分子的三个不同的原子间距离，在 2.5 Å 内。一个较弱的重构水化壳延伸到 15 Å。我们的结果表明，晶体结构决定了水化壳结构。令人惊讶的是，7nm 和 15nm 粒子的晶面表现得像平面。这些发现弥合了氢键网络光谱研究与溶剂化科学理论进展之间的巨大差距。
