Ibrahimkutty Shyjumon, Wagener Philipp, dos Santos Rolo Tomy, Karpov Dmitry, Menzel Andreas, Baumbach Tilo, Barcikowski Stephan, Plech Anton
ANKA/Institute for Photon Science and Synchrotron Radiation, KIT Karlsruhe, Germany.
CENIDE and Dept. of Chemistry, University Duisburg-Essen, Germany.
Sci Rep. 2015 Nov 9;5:16313. doi: 10.1038/srep16313.
Pulsed-laser assisted nanoparticle synthesis in liquids (PLAL) is a versatile tool for nanoparticle synthesis. However, fundamental aspects of structure formation during PLAL are presently poorly understood. We analyse the spatio-temporal kinetics during PLAL by means of fast X-ray radiography (XR) and scanning small-angle X-ray scattering (SAXS), which permits us to probe the process on length scales from nanometers to millimeters with microsecond temporal resolution. We find that the global structural evolution, such as the dynamics of the vapor bubble can be correlated to the locus and evolution of silver nanoparticles. The bubble plays an important role in particle formation, as it confines the primary particles and redeposits them to the substrate. Agglomeration takes place for the confined particles in the second bubble. Additionally, upon the collapse of the second bubble a jet of confined material is ejected perpendicularly to the surface. We hypothesize that these kinetics influence the final particle size distribution and determine the quality of the resulting colloids, such as polydispersity and modality through the interplay between particle cloud compression and particle release into the liquid.
液体中的脉冲激光辅助纳米颗粒合成（PLAL）是一种用于纳米颗粒合成的通用工具。然而，目前人们对PLAL过程中结构形成的基本方面了解甚少。我们通过快速X射线成像（XR）和扫描小角X射线散射（SAXS）来分析PLAL过程中的时空动力学，这使我们能够以微秒级的时间分辨率在从纳米到毫米的长度尺度上探测该过程。我们发现，诸如汽泡动力学等整体结构演变与银纳米颗粒的位置和演变相关。汽泡在颗粒形成过程中起着重要作用，因为它限制了初级颗粒并将它们重新沉积到基底上。在第二个汽泡中，受限颗粒发生团聚。此外，在第二个汽泡坍塌时，一股受限物质射流垂直于表面喷出。我们推测，这些动力学影响最终的颗粒尺寸分布，并通过颗粒云压缩与颗粒释放到液体中的相互作用来决定所得胶体的质量，如多分散性和模态。
