Article
Chemistry, Multidisciplinary
Hailong Li, Margarita Kruteva, Martin Dulle, Zhen Wang, Katarzyna Mystek, Wenhai Ji, Torbjorn Pettersson, Lars Wagberg
Summary: This study investigates the drying behavior of regenerated cellulose gel beads swollen with different nonsolvents on both macroscopic and nanoscale. Depending on the cellulose concentration, the structural evolution of the beads during drying can be classified into three distinct regimes.
Article
Polymer Science
Ekaterina Kostyurina, Judith U. De Mel, Alexandra Vasilyeva, Margarita Kruteva, Henrich Frielinghaus, Martin Dulle, Lester Barnsley, Stephan Foerster, Gerald J. Schneider, Ralf Biehl, Juergen Allgaier
Summary: Amphiphilic polymers exhibit diverse self-assembly behaviors in aqueous solutions. The solution properties and self-assembly morphologies, including single chains, micelles, gels, and ordered liquid crystals, can be systematically tuned by adjusting the lengths of the hydrophilic and hydrophobic building blocks.
Article
Materials Science, Multidisciplinary
Aakash Sharma, Margarita Kruteva, Michaela Zamponi, Sascha Ehlert, Dieter Richter, Stephan Forster
Summary: This study reveals that the segmental dynamics of one-component nanocomposites (OCNC) are significantly influenced by the molecular weight of the grafted polymer. The slower segmental dynamics are observed at low molecular weight, while faster dynamics are observed at high molecular weight. By modeling the local relaxation as a distribution of exponential diffusers, the presence of fast and slow segments in OCNC is identified. The fractional contribution of these segments varies with molecular weight, resulting in different average relaxation times.
PHYSICAL REVIEW MATERIALS
(2022)
Article
Chemistry, Physical
Aakash Sharma, Margarita Kruteva, Michaela Zamponi, Sascha Ehlert, Dieter Richter, Stephan Foerster
Summary: The dynamics of pure oleic acid and grafted oleic acid have been studied using quasielastic neutron scattering. It was found that pure oleic acid mainly undergoes translational diffusion at room temperature, while grafted oleic acid in nanocomposites exhibits uniaxial rotation due to grafting and crowding effects. Additionally, grafted oleic acid shows mobility below the crystallization temperature of pure oleic acid. The results suggest potential research on confined surfactant systems using the approach described in this study.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Ekaterina Kostyurina, Juergen Allgaier, Margarita Kruteva, Henrich Frielinghaus, Agnes Csiszar, Stephan Foerster, Ralf Biehl
Summary: The translocation of macromolecules across cell membranes is crucial for cells and drug delivery. This study investigates the factors influencing membrane partition and translocation rate, and reveals that membrane insertion is a key step determining the translocation rate. Furthermore, it demonstrates that macromolecules with different monomer structures can have similar translocation rates, providing insights for optimizing translocation conditions.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Review
Literary Theory & Criticism
David H. Richter
Article
Geosciences, Multidisciplinary
David H. Richter, Charlotte E. Wainwright
Summary: The exchange of enthalpy and momentum at the air-sea interface plays a crucial role in tropical cyclone (TC) development and intensification. The impact of sea spray, particularly at high wind speeds, has been uncertain. In this study, we conducted high-resolution simulations of a spray-laden TC boundary layer using a coupled large-eddy simulation and Lagrangian cloud model. Our results show that spray droplets have no effect on C-D at wind speeds up to 48 m/s. C-E and C-H are modified initially but quickly relax back to their unladen values due to surface layer saturation, with faster relaxation at higher wind speeds.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Editorial Material
Physics, Multidisciplinary
O. Holderer, A. -C. Genix, M. Kruteva, J. Oberdisse
FRONTIERS IN PHYSICS
(2023)
Article
Physics, Fluids & Plasmas
Colin J. Denzel, Andrew D. Bragg, David H. Richter
Summary: This paper develops a simple stochastic model based on direct numerical simulation to accurately describe the residence times of particles in a particle-laden turbulent flow. The model takes into account the competition between gravity settling and particle-turbulence interaction. Despite its simplicity, the model provides quantitatively accurate predictions of the distribution of particle residence times in the flow. The independent roles of gravity and inertia in governing these residence times are also investigated by varying the Stokes numbers and settling velocities.
PHYSICAL REVIEW FLUIDS
(2023)
Article
Chemistry, Physical
Michael Monkenbusch, Margarita Kruteva, Dieter Richter
Summary: In this work, the single chain dynamic structure factors for five different polymers were compared. The De Gennes approximation was extended to describe the dynamic structure factor. Important results include the approximation of tube diameter by the simple De Gennes structure factor, the description of neutron spin echo spectra using the extended De Gennes structure factor, and the improvement of scattering function representation by introducing non-Gaussianity corrections. The required number of chains spanning the entanglement volume was consistently about 40% larger than that obtained from rheology.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Polymer Science
Aakash Sharma, Margarita Kruteva, Sascha Ehlert, Martin Dulle, Stephan Foerster, Dieter Richter
Summary: Small-angle X-ray scattering is a powerful technique for investigating the spatial arrangements of polymer-grafted nanoparticles in nanocomposites. However, the commonly used hard sphere model fails to accurately describe the density of the grafted polymer, leading to inappropriate quantitative descriptions of nanoparticle assemblies. By analyzing the scattering data and considering the polymer-induced interactions, we are able to establish quantitative relations between the nanoparticle assembly and the polymer structure in the nanocomposites.
Article
Polymer Science
Margarita Kruteva, Michael Monkenbusch, Juergen Allgaier, Wim Pyckhout-Hintzen, Lionel Porcar, Dieter Richter
Summary: We conducted a systematic investigation on ring-linear blends using small angle neutron scattering, where we varied the ring volume fraction in a long linear matrix or the matrix length at a low ring fraction. We observed that the ring radius of gyration decreased with increasing ring fraction and approached the value of the ring melt at a volume fraction of φ(R) = 0.5. The fractal dimension, which was close to a Gaussian conformation at low φ(R), decreased to the value of the ring melt. The ring size was found to be independent of the host length, except for very short matrices.