A joined publication  “Time-Resolved Analysis of the Structural Dynamics of Assembling Gold Nanoparticles” led by Prof. Martin Trebbin’s group  is accepted and now in an early-view-stage at ACS Nano.

Abstract: The hydrophobic collapse is a structural transition of grafted polymer chains in a poor solvent. Although such a transition seems an intrinsic event during clustering of polymer-stabilized nanoparticles in the liquid phase, it has not been resolved in real time. In this work, we implemented a microfluidic 3D-flow-focusing mixing reactor equipped with real-time analytics, small-angle X-ray scattering (SAXS), and UV–vis–NIR spectroscopy to study the early stage of cluster formation for polystyrene-stabilized gold nanoparticles. The polymer shell dynamics obtained by in situ SAXS analysis and numerical simulation of the solvent composition allowed us to map the interaction energy between the particles at early state of solvent mixing, 30 ms behind the crossing point. We found that the rate of hydrophobic collapse depends on water concentration, ranging between 100 and 500 nm/s. Importantly, we confirmed that the polymer shell collapses prior to the commencement of clustering.

Our recent paper “Resonance Microwave Measurements of an Intrinsic Spin-Orbit Coupling Gap in Graphene: A Possible Indication of a Topological State” by J. Sichau, M. Prada, T. Anlauf, T. J. Lyon, B. Bosnjak, L. Tiemann, and R. H. Blick published in Physical Review Letters has been highlighted by Nature Nanotechnology (https://doi.org/10.1038/s41565-019-0409-y).

Abstract: In 2005, Kane and Mele [Phys. Rev. Lett. 95, 226801 (2005)] predicted that at sufficiently low energy, graphene exhibits a topological state of matter with an energy gap generated by the atomic spin-orbit interaction. However, this intrinsic gap has not been measured to this date. In this Letter, we exploit the chirality of the low-energy states to resolve this gap. We probe the spin states experimentally by employing low temperature microwave excitation in a resistively detected electron-spin resonance on graphene. The structure of the topological bands is reflected in our transport experiments, where our numerical models allow us to identify the resonance signatures. We determine the intrinsic spin-orbit bulk gap to be exactly 42.2μeV. Electron-spin resonance experiments can reveal the competition between the intrinsic spin-orbit coupling and classical Zeeman energy that arises at low magnetic fields and demonstrate that graphene remains to be a material with surprising properties.