A5027285945- Polymer Surface Interaction Studies
- Dendrimers and Hyperbranched Polymers
- Nuclear Physics and Applications
- Atomic and Subatomic Physics Research
- Surface Modification and Superhydrophobicity
- Advanced Condensed Matter Physics
- Characterization and Applications of Magnetic Nanoparticles
- Surfactants and Colloidal Systems
- Magnetic and transport properties of perovskites and related materials
- Magnetic properties of thin films
- Pickering emulsions and particle stabilization
- Advanced biosensing and bioanalysis techniques
- Lipid Membrane Structure and Behavior
- Hydrogels: synthesis, properties, applications
- High-pressure geophysics and materials
- RNA Interference and Gene Delivery
- Electrospun Nanofibers in Biomedical Applications
- NMR spectroscopy and applications
- Force Microscopy Techniques and Applications
- Adhesion, Friction, and Surface Interactions
- ZnO doping and properties
- Advanced NMR Techniques and Applications
- Multiferroics and related materials
- Semiconductor materials and devices
- Spectroscopy and Quantum Chemical Studies
Technical University of Darmstadt
2019-2024
Technical University of Munich
2016-2022
Heinz Maier-Leibnitz Zentrum
2014-2019
Max Planck Institute for Solid State Research
2012-2018
Max Planck Society
2014-2017
Max Planck Computing and Data Facility
2014-2017
Academy of Sciences of Moldova
2015
Lomonosov Moscow State University
2015
Kazan Federal University
2015
Universität Greifswald
2010-2012
Using neutron reflectivity, the internal structure of polyelectrolyte multilayers is described on nanoscale. Each film consists a protonated and deuterated block, built from x y polycation/polyanion bilayers, respectively. The number bilayers N = + kept constant; position interface between blocks varied systematically. polyanion poly(styrenesulfonate) (PSS), polycation poly(allylamine hydrochloride) (PAH) or poly(diallyldimethylammonium chloride) (PDADMAC). Always, first four to five are...
A common feature of ionic liquids composed cations with long aliphatic side chains is structural heterogeneities on the nanometer length scale. This so-called microphase separation arises from clustering moieties. The temperature dependence liquid bulk structure was studied by small-angle X-ray and neutron scattering for a set methylimidazolium ([C18C1im]+, [C22C1im]+) based tris(pentafluoroethyl)trifluorophosphate ([FAP]-), bis(trifluoromethylsulfonyl)imide ([NTf2]-),...
Two polyaspartates bearing ortho-fluorinated azobenzenes (pFAB) as photo-responsive groups in the side chain were synthesized: PpFABLA (1) and co-polyaspartate PpFABLA-co-PBLA [11, 75%(n/n) content]. As a consequence of E/Z-isomerization chain, undergoes visible-light-induced reversible coil-helix transition solution: Green light (525 nm) affords coil, violet (400 helix. pFAB significantly increases thermal stability Z-isomer at 20 °C (t1/2 = 66 d for Z-isomer) effectively counters favored...
The internal interfaces of polyelectrolyte multilayers are investigated with neutron reflectivity. films made from poly(diallyldimethylammonium) (PDADMA), poly(styrenesulfonate) (PSS), and deuterated PSS-d. Each film consists a protonated block. roughness is smallest next to the film/air interface increases number layer pairs away until metastable state reached. Both final interdiffusion constant increase salt concentration in deposition solution PDADMA polymer weight. increased mobility...
We have investigated the interactions between cationic poly(amidoamine) (PAMAM) dendrimers of generation 4 (G4), a potential gene transfection vector, with net-anionic model biomembranes composed different ratios zwitterionic phosphocholine (PC) and anionic phospho-L-serine (PS) phospholipids. Two types membranes were used: solid-supported bilayers, prepared lipids carrying palmitoyl-oleoyl (PO) diphytanoyl (DPh) acyl chains, free-standing formed at interface two aqueous droplets in oil...
PNIPAM microgels form inhomogeneous network-like structures with microgel depleted and bearing zones when confined in foam films.
The complex interaction of polyelectrolyte multilayers (PEMs) physisorbed onto end-grafted polymer brushes with focus on the temperature-responsive behavior system is addressed in this work. investigated brush/multilayer composite consists a poly(styrene sulfonate)/poly(diallyldimethylammonium chloride) (PSS/PDADMAC) multilayer deposited poly(N-isopropylacrylamide-b-dimethylaminoethyl methacrylate) P(NIPAM-b-DMAEMA) brush. Ellipsometry and neutron reflectometry were used to monitor brush...
Linearly assembled polyelectrolyte multilayers (PEMs) are prepared by sequential adsorption of polyanions and polycations from 0.1 mol/L NaCl. The internal structure PEMs is investigated with neutron reflectivity. films made poly(ethylenimine) (PEI), poly(diallyldimethylammonium) (PDADMA) poly(styrenesulfonate) (PSS or deuterated PSS-d). Each film consists a protonated block, built m n polycation/polyanion layer pairs, respectively. Annealing in salt solution (1 NaCl) allows the...
The high resolution neutron/ X-ray contrast reflectometer NREX, operated by the Max Planck Institute for Solid State Research, is designed determination of structural and magnetic properties surfaces, interfaces, thin film systems.
The structure and dynamics of nanostructure films formed by mixtures soy phosphatidylcholine glycerol dioleate at the silicon-aqueous interface were studied grazing incidence neutron spin echo spectroscopy (GINSES), specular off-specular reflectometry, small-angle X-ray diffraction. Reverse hexagonal (HII) micellar cubic phase (Fd3m) layers solid-liquid have been identified with reflectometry measurements. A preferred orientation liquid crystalline (LC) domains was observed only for...
Osteoarthritis is the most common arthropathy in western civilization. It primarily caused by degeneration of lipid-coated cartilage, leading to increased friction joints. Hyaluronic acid (HA), a negatively charged polysaccharide and main component synovial fluid, held responsible for joint lubrication. believed that HA, adsorbed forms protective layer against wear. Studies have shown concentration molecular weight (MW) HA are reduced joints suffering from osteoarthritis. On basis these...
Drug/bilayer interactions are fundamental in determining the action mechanism of active ingredients. Neutron techniques represent unique tools for having a clear comprehension such interactions.
Depth-sensitive magnetic, structural, and chemical characterization is important in the understanding optimization of physical phenomena emerging at interfaces transition metal oxide heterostructures. In a simultaneous approach we have used polarized neutron resonant x-ray reflectometry to determine magnetic profile across atomically sharp ferromagnetic ${\mathrm{La}}_{0.67}{\mathrm{Sr}}_{0.33}{\mathrm{MnO}}_{3}$/multiferroic ${\mathrm{BiFeO}}_{3}$ bilayers with subnanometer resolution....
We report on ellipsometric studies of the nonlinear growth regimes electrostatically assembled polyelectrolyte multilayer films under in situ conditions. Poly(styrenesulfonate) (PSS) and poly(diallylmethylammonium) (PDADMA) with different molecular weights 0.1 mol/L NaCl are used. Always, linear is preceded by a parabolic regime. For made from binary PDADMA mixtures, compositions film adsorption solution nearly identical. To explain these findings, model that describes quantitatively...
The structure of sugar-surfactant-based bicontinuous microemulsions in the bulk and at hydrophilic hydrophobic solid planar surfaces was studied by means neutron scattering techniques (SANS, NR, GISANS). In particular, influence type oil (tetradecane methyl oleate) on structural properties vicinity investigated different oil-to-water ratios. case surfaces, analysis length density profiles reveals an induced ordering water domains perpendicular to solid–liquid interface both sets...
The modelling of scattering data from foams is very challenging due to the complex structure and therefore often reduced fitting single peak positions or feature mimicking. This article presents a more elaborate model describe small-angle neutron (SANS) foams. takes into account geometry foam bubbles based on an incoherent superposition reflectivity curves arising films (SAS) contribution plateau borders. capable describing complete curve stabilized by standard cationic surfactant...
To describe the swelling of polyelectrolyte multilayers (PEMs) on a molecular scale, PEM architecture is varied. The polyanion poly(styrenesulfonate) (PSS) and polycation poly(allylamine hydrochloride) (PAH). either consists 10 protonated bilayers (p10), deuterated (d10), or two different blocks, p5d5 d5p5. Prior to exposure 100% relative humidity (RH) D2O H2O, immersed in liquid respectively. obtained scattering length density profiles provide insight into exchange rates constituent...
The combination of polyelectrolyte multilayers (PEMs) and end-grafted brushes represents a valuable approach to the design complex organic composite materials with tailored responsive properties. This article addresses correlation between swelling properties composites their internal structure. Here, we present 2-(methacryloyloxy)ethyl-trimethylammonium chloride (PMETAC) covered poly(sodium styrenesulfonate) (PSS) poly(diallyldimethylammonium) (PDADMAC) PEMs characterize them under various...
Epitaxial ${\mathrm{La}}_{1.85}{\mathrm{Sr}}_{0.15}{\mathrm{CuO}}_{4}/{\mathrm{La}}_{2/3}{\mathrm{Ca}}_{1/3}{\mathrm{MnO}}_{3}$ (LSCO/LCMO) superlattices on $(001)$-oriented ${\mathrm{LaSrAlO}}_{4}$ substrates have been grown with pulsed laser deposition technique. Their structural, magnetic, and superconducting properties determined in situ reflection high-energy electron diffraction, x-ray specular neutron reflectometry, scanning transmission microscopy, electric transport, magnetization...
We report an investigation of the structural and electronic properties hybrid superconductor/ferromagnet (S/F) bilayers composition Nb/Cu$_{60}$Ni$_{40}$ prepared by magnetron sputtering. X-ray neutron reflectometry show that both overall interfacial roughness vertical correlations different interfaces are lower for heterostructures deposited on Al$_2$O$_3$(1$\bar{1}$02) substrates than those Si(111). Mutual inductance experiments were then used to study influence superconducting transition...
Recent progress in neutron spin-echo spectroscopy by means of longitudinal Modulation IntEnsity with Zero Effort (MIEZE) is reviewed. Key technical characteristics are summarized which highlight that the parameter range accessible momentum and energy, as well its limitations, extremely understood controlled. Typical experimental data comprising quasi-elastic inelastic scattering presented, featuring magneto-elastic coupling crystal field excitations Ho2Ti2O7, skyrmion lattice to paramagnetic...