Letzel Alexander, Reich Stefan, Dos Santos Rolo Tomy, Kanitz Alexander, Hoppius Jan, Rack Alexander, Olbinado Margie P, Ostendorf Andreas, Gökce Bilal, Plech Anton, Barcikowski Stephan
Department of Technical Chemistry I and Center for Nanointegration Duisburg-Essen (CENIDE) , University of Duisburg-Essen , Universitätsstraße 7 , 45141 Essen , Germany.
Institute for Photon Science and Synchrotron Radiation , Karlsruhe Institute of Technology (KIT) , Hermann-von-Helmholtz-Platz 1 , 76344 Eggenstein-Leopoldshafen , Germany.
Langmuir. 2019 Feb 26;35(8):3038-3047. doi: 10.1021/acs.langmuir.8b01585. Epub 2019 Feb 12.
Laser ablation of gold in liquids with nanosecond laser pulses in aqueous solutions of inorganic electrolytes and macromolecular ligands for gold nanoparticle size quenching is probed inside the laser-induced cavitation bubble by in situ X-ray multicontrast imaging with a Hartmann mask (XHI). It is found that (i) the in situ size quenching power of sodium chloride (NaCl) in comparison to the ablation in pure water can be observed by the scattering contrast from XHI already inside the cavitation bubble, while (ii) for polyvinylpyrrolidone (PVP) as a macromolecular model ligand an in situ size quenching cannot be observed. Complementary ex situ characterization confirms the overall size quenching ability of both additive types NaCl and PVP. The macromolecular ligand as well as its monomer N-vinylpyrrolidone (NVP) are mainly effective for growth quenching of larger nanoparticles on later time scales, leading to the conclusion of an alternative interaction mechanism with ablated nanoparticles compared to the electrolyte NaCl, probably outside of the cavitation bubble, in the surrounding liquid phase. While monomer and polymer have similar effects on the particle properties, with the polymer being slightly more efficient, only the polymer is effective against hydrodynamic aggregation.
通过带有哈特曼掩膜的原位X射线多对比度成像（XHI），在激光诱导的空化泡内部探究了在无机电解质和金纳米颗粒尺寸猝灭的大分子配体的水溶液中，用纳秒激光脉冲对液体中的金进行激光烧蚀的情况。研究发现：（i）与在纯水中的烧蚀相比，氯化钠（NaCl）的原位尺寸猝灭能力可通过空化泡内部XHI的散射对比度观察到，而（ii）对于作为大分子模型配体的聚乙烯吡咯烷酮（PVP），无法观察到原位尺寸猝灭现象。补充的非原位表征证实了NaCl和PVP这两种添加剂类型的整体尺寸猝灭能力。大分子配体及其单体N-乙烯基吡咯烷酮（NVP）主要在较晚的时间尺度上对较大纳米颗粒的生长猝灭有效，由此得出结论，与电解质NaCl相比，与烧蚀纳米颗粒的相互作用机制不同，可能在空化泡之外，即在周围液相中。虽然单体和聚合物对颗粒性质有相似的影响，聚合物的效率略高，但只有聚合物能有效对抗流体动力学聚集。
