A5059037487- Material Dynamics and Properties
- Surfactants and Colloidal Systems
- Quantum Dots Synthesis And Properties
- Phase Equilibria and Thermodynamics
- Spectroscopy and Quantum Chemical Studies
- Advanced X-ray Imaging Techniques
- nanoparticles nucleation surface interactions
- Gold and Silver Nanoparticles Synthesis and Applications
- Microfluidic and Capillary Electrophoresis Applications
- Innovative Microfluidic and Catalytic Techniques Innovation
- Liquid Crystal Research Advancements
- Hemophilia Treatment and Research
- Particle physics theoretical and experimental studies
- Chalcogenide Semiconductor Thin Films
- Advanced Electron Microscopy Techniques and Applications
- Hydrogels: synthesis, properties, applications
- Protein Interaction Studies and Fluorescence Analysis
- Hemoglobinopathies and Related Disorders
- Mesoporous Materials and Catalysis
- Particle Accelerators and Free-Electron Lasers
- Theoretical and Computational Physics
- Microfluidic and Bio-sensing Technologies
Deutsches Elektronen-Synchrotron DESY
2018-2022
Max Planck Institute for the Structure and Dynamics of Matter
2018-2022
Hamburg Centre for Ultrafast Imaging
2018-2022
Centre for Sight
2019-2020
Dynamics and kinetics in soft matter physics, biology, nanoscience frequently occur on fast (sub)microsecond but not ultrafast timescales which are difficult to probe experimentally. The European X-ray Free-Electron Laser (European XFEL), a megahertz hard source, enables such experiments via taking series of diffraction patterns at repetition rates up 4.5 MHz. Here, we demonstrate photon correlation spectroscopy (XPCS) with submicrosecond time resolution samples the XFEL. We show that XFEL...
We investigate the out-of-equilibrium dynamics of a colloidal gel obtained by quenching suspension soft polymer-coated gold nanoparticles close to and below its gelation point using X-ray Photon Correlation Spectroscopy (XPCS). A faster relaxation process emergent from localized motions reveals dynamically-arrested network at nanoscale as key signature process. find that slower is hyperdiffusive with compressed exponential form, consistent stress-driven processes. Specifically, we use...
Many soft-matter systems are composed of macromolecules or nanoparticles suspended in water. The characteristic times at intrinsic length scales a few nanometres fall therefore the microsecond and sub-microsecond time regimes. With development free-electron lasers (FELs) fourth-generation synchrotron light-sources, time-resolved experiments such ranges will become routinely accessible near future. In present work we report our findings on prototypical systems, charge-stabilized silica...
We present the structure and dynamics of highly concentrated core–shell nanoparticles composed a silica core poly(N-isoproylacrylamide) (PNIPAm) shell suspended in water. With X-ray photon correlation spectroscopy, we are able to follow dynamical changes over volume phase transition PNIPAm at LCST = 32 °C. On raising temperature beyond LCST, structural relaxation times continue decrease. The effect is accompanied by from stretched compressed exponential shape intensity autocorrelation...
We report on the self-assembly of gold nanoparticles coated with a soft poly(ethylene glycol) shell studied by X-ray cross-correlation analysis. Depending initial concentration used, structurally heterogeneous films were formed. The feature hot spots dominating four- and sixfold local order patch sizes few micrometres, containing 10 4 –10 5 particles. amplitude parameters suggested that minimum sample amount was necessary to form well ordered structures. Furthermore, increasing variation in...
We study the structure and dynamics of aqueous dispersions densely packed core-shell nanoparticles composed a silica core poly(N-isoproylacrylamide) (PNIPAm) shell as function temperature concentration. With small angle X-ray scattering (SAXS) photon correlation spectroscopy (XPCS) we shed light on structural dynamical changes thermo-responsive colloidal nanogel during its volume phase transition at lower critical solution (LCST) 32 °C. A distinct dependency particle number concentration...
We study the structure and dynamics of colloidal particles with a spherical hard core thermo-responsive soft shell over whole phase diagram by means small-angle x-ray scattering photon correlation spectroscopy. By changing effective volume fraction temperature particle concentration, liquid, repulsive glass. attractive gel phases are observed. The slow down increasing in liquid reflect Vogel-Fulcher-Tamann behavior known for fragile glass formers. find liquid-glass transition above 50 vol.%...
An X-ray cross-correlation study of the local orientational order in self-assembled films made from PEGylated gold nanoparticles is presented. The structure this model system dominated by four- and sixfold order. Coadsorption shorter ligands particle's ligand layer variation salt concentration suspension prior to self-assembly result a change degree reduced after addition. This decrease less pronounced for fourfold symmetry. results presented here suggest complex symmetry-selective formation...
Colloidal nanocrystals (NC) are known to self-organize into superlattices that promise many applications ranging from medicine optoelectronics. Recently, the formation of high-quality PEGylated gold NC was reported at high hydrostatic pressure and salt concentrations. Here, we study kinetics these after jumps beyond their crystallisation by means small-angle X-ray scattering with few ms experimental resolution. The timescale found be reduced larger width jump. This is connected an increase...
We study the structure and dynamics of poly(N-isopropylacrylamide) (PNIPAm) core-shell nanogels dispersed in aqueous trimethylamine N-oxide (TMAO) solutions by means small-angle X-ray scattering photon correlation spectroscopy (XPCS). Upon increasing temperature above lower critical solution PNIPAm at 33 °C, a colloidal gel is formed as identified an increase I(q) small q well slowing down sample various orders magnitude. With TMAO concentration gelation transition shifts linearly to...
We applied shear to a silica nanoparticle dispersion in microfluidic jet device and observed direction-dependent structure along across the flow direction. The asymmetries of diffraction patterns were evaluated by x-ray cross correlation analysis. For different Rayleigh nozzle sizes shapes, we measured decay shear-induced ordering after cessation shear. At large tube small rates, characteristic times become longer, but Péclet-weighted do not scale linearly with Péclet numbers. By modeling...
We demonstrate the pressure-induced formation of supercrystals made from PEGylated gold nanorods (NRs) in aqueous suspension. Utilizing combined effect hydrostatic pressure and salt on solubility organic poly(ethylene glycol) (PEG) shell that passivates NRs, reversible two-dimensional hexagonal has been observed by means small-angle X-ray scattering. The dependence crystal lattice's structural parameters is determined. By time-resolved measurements performed after a jump, growth process...
We introduce the setup of a versatile sample chamber for x-ray scattering experiments on liquids delivered by μ-jets. The simple implementation at light sources, adaptability to different nozzle types, and availability microscope observation jet flow allow its broad application. In combination with an inbuilt recycling circle, continuous operation is provided. Functionality system was demonstrated in rheology study PETRA III.