Article
Chemistry, Multidisciplinary
Cicely Shillingford, Brandon M. Kim, Marcus Weck
Summary: Capillary assembly of liquid particles (CALP) is a microfabrication strategy for engineering arbitrarily shaped polymer colloids. CALP demonstrates versatility by engineering geometrically diverse Janus and patchy colloids using consecutive assembly and heterogeneous coassembly. It enables the design and fabrication of colloids with complex internal construction to target hierarchical functional materials, with the potential for further processing into colloid-based microscale devices.
Article
Chemistry, Multidisciplinary
Doora Takacs, Tamas Szabo, Andrej Jamnik, Matija Tomsic, Istvan Szilagyi
Summary: In this study, the homoaggregation of polystyrene microplastics (MPs) and heteroaggregation of MPs with anionic clay minerals (Layered Double Hydroxide, LDH) in different salt solutions were investigated. The stability of particles was affected by the type and ionic strength of the salt, and the interaction between MPs and LDH can be explained by DLVO theory. The adsorption of LDH resulted in neutralization and reversal of MPs surface charge, leading to rapid aggregation.
Article
Chemistry, Physical
Archit Dani, Mohsen Yeganeh, Charles Maldarelli
Summary: The cluster formation and self-assembly of floating colloids at a fluid/fluid interface involve a delicate force balance among lateral interaction forces, viscous resistance, and thermal fluctuations. The study shows that as the colloid dimensions decrease, thermal forces become important and affect the self-assembly into ordered patterns and crystal structures. Numerical simulations are used to describe the assembly of particles at a liquid-liquid interface, considering capillary attraction, electrostatic repulsion, thermal fluctuations, and hydrodynamic interactions. The results suggest that cluster formation, fractal growth, and particle ordering are more likely to occur at larger values of the Pe numbers.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2022)
Article
Chemistry, Physical
Rachel S. Hendley, Isaac Torres-Diaz, Michael A. Bevan
Summary: By identifying analytical potentials for dipole-field and dipole-dipole interactions, we match experimental and simulated configurations of anisotropic epoxy colloidal particles in high frequency AC electric fields. The inverse Monte Carlo simulation algorithm helps determine optimal fits of analytical potentials to capture experimental observations. The stretched point dipole potential is found suitable at all concentrations, field amplitudes, and degrees of ordering, showing simplicity, accuracy, and adjustability for modeling field mediated microstructures and assembly of systematically varying anisotropic particle shapes.
Article
Physics, Multidisciplinary
Carolina van Baalen, Jacopo Vialetto, Lucio Isa
Summary: This study explores the control of crystallization of colloidal particles at oil-water interfaces using oil-soluble electrolytes. The results show that the repulsion among particles can be continuously tuned by introducing nanomolar amounts of an organic salt into the oil.
PHYSICAL REVIEW LETTERS
(2023)
Article
Chemistry, Physical
Nestor M. de los Santos-Lopez, Gabriel Perez-Angel, Jose M. Mendez-Alcaraz, Ramon Castaneda-Priego
Summary: The article systematically studies the depletion interactions between colloidal particles, focusing on how the composition of depletants drives the competition between attraction and repulsion. Results are obtained through theoretical analysis and computer simulations.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Multidisciplinary Sciences
Lucia Baldauf, Erin G. Teich, Peter Schall, Greg van Anders, Laura Rossi
Summary: Creating materials with independently controllable structures at multiple scales requires breaking naturally occurring hierarchies. This study demonstrates that shape and interaction decoupling can occur in colloidal cuboids, leading to the formation of preassembled mesoscale building blocks for larger-scale structures. The results highlight the potential of preassembled building blocks for hierarchical materials design.
Article
Physics, Applied
Raul Josue Hernandez-Hernandez, Thomas M. Fischer, Pietro Tierno
Summary: This study investigates the pair interactions between magnetically driven colloidal microrotors with an anisotropic shape. The particles interact through dipolar forces and hydrodynamic interactions (HIs) when they approach each other. When the magnetic field is close to a specific angle, dipolar interactions vanish and the pair's dynamics are solely driven by HIs. A theoretical description is provided to understand the role of anisotropy on the collective dynamics.
APPLIED PHYSICS LETTERS
(2022)
Article
Chemistry, Physical
Dominik Lips, Eric Cereceda-Lopez, Antonio Ortiz-Ambriz, Pietro Tierno, Artem Ryabov, Philipp Maass
Summary: The study investigates the collective transport properties of colloidal particles in a rotating ring of optical traps. It is found that the particles are driven by a vortex flow of the surrounding fluid in the corotating reference frame. The jamming behavior observed with increasing particle density is attributed to enhanced energetic barriers between the optical traps due to hydrodynamic interactions. The study highlights the importance of considering the driving mechanism and hydrodynamic interactions in soft matter and biological systems.
Article
Chemistry, Physical
Binghan Liu, Gary S. Grest, Shengfeng Cheng
Summary: Molecular dynamics simulations demonstrate that a binary solvent can be used to stratify colloidal mixtures during rapid drying by creating concentration gradients.
Article
Chemistry, Physical
Albert Tianxiang Liu, Marek Hempel, Jing Fan Yang, Allan M. Brooks, Ana Pervan, Volodymyr B. Koman, Ge Zhang, Daichi Kozawa, Sungyun Yang, Daniel I. Goldman, Marc Z. Miskin, Andrea W. Richa, Dana Randall, Todd D. Murphey, Tomas Palacios, Michael S. Strano
Summary: Robots have components that work together to accomplish a task. Colloidal robots are particles capable of functions such as sensing, computation, communication, locomotion, and energy management that are all controlled by the particle itself. Their design and synthesis is an emerging area of interdisciplinary research drawing from materials science, colloid science, self-assembly, robophysics, and control theory.
Article
Chemistry, Physical
Sara Haddadi, Marie Skepo, Patric Jannasch, Sophie Manner, Jan Forsman
Summary: This research successfully synthesized polymer clusters with highly anisotropic structures in aqueous solution, controlled by adjusting conditions and manipulating ionic strength.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2021)
Article
Chemistry, Physical
Matthew A. Dorsey, Orlin D. Velev, Carol K. Hall
Summary: In this paper, the self-assembling characteristics of a new class of microscopic cube-shaped colloids with a magnetic dipole were investigated. Simulation results showed that these particles tend to form either single- or double-stranded assemblies with unique structures and phase diagrams in the temperature-density plane. These findings have important implications for the development of materials with controllable properties.
Article
Physics, Applied
Yoshika Yato, Rei Tatsumi, Yoshiko Tsuji
Summary: The study investigates how the fabrication conditions of self-assembled colloidal films affect their structural color. Two numerical simulation techniques are combined to analyze the microstructure and calculate the structural color intensity. The study suggests that a larger surface tension of the solvent and a smaller drying rate improve the structural color intensity.
APPLIED PHYSICS LETTERS
(2023)
Article
Polymer Science
Vincenzo Calabrese, Stylianos Varchanis, Simon J. Haward, Amy Q. . Shen
Summary: Understanding the hydrodynamic alignment of colloidal rods in polymer solutions is crucial for producing structurally ordered materials. This study analyzes the alignment of colloidal rods suspended in polymer solutions and compares it to the case where additional colloidal rods provide crowding in a pure solvent. The dynamics of the polymer is found to govern the shear-induced alignment of colloidal rods, with the Weissenberg number as the control parameter for alignment. Additionally, it is shown that the alignment of colloidal rods follows a universal trend regardless of the crowding environment.
Article
Chemistry, Physical
Martin Wittmann, Mihail N. Popescu, Alvaro Dominguez, Juliane Simmchen
Summary: The experiment with spherically symmetric active TiO2 particles at an oil-water interface confirmed that collective dynamics can arise from activity-induced gradients, leading to long-ranged Marangoni flows even when particles are not self-propelled. The addition of a nonionic surfactant was shown to influence the emergence of collective motion, with dynamics dependent on particle coverage in the monolayer. The experimental observations were discussed within a simple theoretical mean-field model.
EUROPEAN PHYSICAL JOURNAL E
(2021)
Article
Materials Science, Multidisciplinary
Berthold Reisz, Eelco Empting, Matthias Zwadlo, Martin Hodas, Giuliano Duva, Valentina Belova, Clemens Zeiser, Jan Hagenlocher, Santanu Maiti, Alexander Hinderhofer, Alexander Gerlach, Martin Oettel, Frank Schreiber
Summary: Blended organic thin films, including pure and mixed films of CuPc and C60, were studied for their growth processes and morphologies. Experimental results showed the formation of a smooth wetting layer followed by rapid roughening in pure CuPc films, while C60 exhibited fast formation of distinct islands at an early growth stage.
PHYSICAL REVIEW MATERIALS
(2021)
Article
Chemistry, Physical
James F. Lutsko, Martin Oettel
Summary: The original derivation of power functional theory is reworked in detail to clarify and simplify the logic and make explicit the various functional dependencies. Issues with the original development are noted and a modification is suggested to avoid them. An alternative interpretation of the results is proposed, showing surprising similarities to classical density functional theory.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Physical
Young Choon Park, Ajith Perera, Rodney J. Bartlett
Summary: In this work, the time-independent and time-dependent EOM-CC oscillator strengths were implemented beyond the dipole approximation, including contributions beyond the quadrupole moment. This allows for the calculation of intensities for dipole inactive transitions, such as pre-edge transitions in metal K-edge spectra. The use of second-order oscillator strengths is demonstrated through TI-EOM-CCSD and TD-EOM-CCSD spectra of Ti4+ atoms.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Physical
Saswati Ganguly, Gaurav Prakash Shrivastav, Shang-Chun Lin, Johannes Haering, Rudolf Haussmann, Gerhard Kahl, Martin Oettel, Matthias Fuchs
Summary: Different types of defects play a significant role in the mechanical response of complex crystals close to melting or at finite temperatures. Conventional elasticity theory fails to explain the motion of point defects in ordered crystalline structures. In this study, a first principles theoretical framework derived from microscopic equations of motion is used to investigate the elastic properties of a crystal with a high concentration of point defects. Predictions about the mechanical properties are validated through deformation experiments in molecular dynamics simulations.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Review
Chemistry, Physical
Alvaro Dominguez, Mihail N. Popescu
Summary: Phoresis, a classic example of particle transport driven by thermodynamic gradients, is enjoying renewed research interest due to its relevance to the motility of chemically active particles and technological advancements. This review focuses on the general framework of phoresis and self-phoresis, using chemophoresis as a case study, and discusses the simplest extension of the theory to account for correlations in the fluid. It is found that self-phoresis can no longer be represented as phoresis in a self-generated composition gradient, shifting the paradigm from the ideal case.
CURRENT OPINION IN COLLOID & INTERFACE SCIENCE
(2022)
Article
Chemistry, Physical
Alexander Hinderhofer, Jan Hagenlocher, Alexander Gerlach, Joachim Krug, Martin Oettel, Frank Schreiber
Summary: Understanding the growth behavior of binary mixtures and its connection to the bulk phase behavior is a major challenge. In this study, we used X-ray reflectivity to determine the surface roughness and found systematic behavior depending on the intermixing, co-crystallization, or phase separation in the mixed films. Kinetic Monte Carlo simulations provided evidence that the lowered step edge barrier in the mixed films is induced by reduced in-plane crystallinity.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Physical
Christian Beck, Marco Grimaldo, Hender Lopez, Stefano Da Vela, Benedikt Sohmen, Fajun Zhang, Martin Oettel, Jean-Louis Barrat, Felix Roosen-Runge, Frank Schreiber, Tilo Seydel
Summary: This study investigates the dependence of diffusion dynamics of macromolecules in biological systems on volume fraction using a simplified model system. The results suggest that a simple colloid picture accurately describes the short-time diffusion in binary mixtures.
JOURNAL OF PHYSICAL CHEMISTRY B
(2022)
Article
Chemistry, Physical
Frank Hirschmann, Hender Lopez, Felix Roosen-Runge, Tilo Seydel, Frank Schreiber, Martin Oettel
Summary: The researchers developed a coarse-grained, structure-based, low-resolution, 6-bead model for bovine serum albumin (BSA) and compared it with a 12-bead model for immunoglobulin G (IgG). They studied the effects of packing and flexibility on the behavior of these models in denser solutions. They also determined the effective sphere sizes of BSA.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Sahana Kale, Achim Lederer, Martin Oettel, Hans Joachim Schoepe
Summary: PMMA-PHSA particles have been used as a hard sphere model system since the 1980s. We investigate the fluid structure of fluorescent particles in three different solvents and compare them with analytical theory and computer simulations. The results show hard sphere behavior in decalin-TCE and charged sphere behavior in decalin-CHB and decalin-CHB-TBAB solvents, with reduced screening in the latter system compared to the bulk solvent.
Correction
Physics, Fluids & Plasmas
E. Empting, M. Klopotek, A. Hinderhofer, F. Schreiber, M. Oettel
Article
Physics, Fluids & Plasmas
E. Empting, N. Bader, M. Oettel
Summary: This study investigates the roughness and orientational order in thin films of anisotropic particles through kinetic Monte Carlo simulations. The results show that increasing anisotropy leads to a preferred orientation in the film, accompanied by non-equilibrium roughening effect and reordering in the film.
Article
Physics, Fluids & Plasmas
M. Maeritz, M. Oettel
Summary: A density functional based on fundamental measure theory is employed to study droplet states of lattice gas with next-neighbor attractions in three-dimensional finite systems. The findings show a sequence of droplets transitioning to cylinders and planar slabs, along with additional effects observed in the chemical potential curve upon temperature decrease. The analysis of the surface tension behavior reveals a dominant 1/Rs2 contribution with a hint of weak logarithmic contribution, which is smaller than the universal value predicted by field-theoretic methods.
Article
Physics, Fluids & Plasmas
M. Maeritz, M. Oettel
Summary: Researchers constructed a density functional for lattice gas or Ising model on square and cubic lattices based on lattice fundamental measure theory, mapping the model to a multicomponent model of hard particles and introducing polymer clusters to treat nearest-neighbor attractions. The resulting density functional for this nonadditive hard model showed significant improvement in planar interface tensions compared to standard mean-field functional and was close to simulation results in three dimensions.
Article
Physics, Fluids & Plasmas
E. Empting, M. Klopotek, A. Hinderhofer, F. Schreiber, M. Oettel
Summary: Thin-film growth is investigated in two types of lattice gas models with unequal interaction energy parameters for substrate and film particles. The models exhibit dynamic layering and flattening transitions, with the difference between particle-substrate and particle-particle interactions playing a central role for film morphology evolution at intermediate times.