Soft glassy materials often consist of deformable objects. Here, we use a two-dimensional assembly of semi-flexible ring polymers as a model system to investigate how polydispersity in particle stiffness or size influences the onset of glassy dynamics. In simulations at fixed polydispersity (30%), we find that stiffness dispersity drives most rings into elongated conformations at high densities, leading to orientationally ordered structures that cause dynamical slowing down. In contrast, size dispersity generates a bimodal population: small rings remain circular and act as rigid inclusions, while large rings elongate, producing frustration that delays arrest. Real-space maps of bond relaxation reveal strikingly different pathways of dynamical heterogeneity, with long-lived domains persisting under stiffness dispersity but rapidly percolating relaxation under size dispersity. Moreover, local correlations between ring shape, orientational order, and mobility show that stiffness dispersity produces dynamics that are strongly structure-sensitive, whereas size dispersity activates motion from both circular and elongated populations. By linking microscopic deformability to emergent glassy dynamics, this study identifies how the nature of polydispersity controls the relaxation pathways of soft glasses.

For studying the structure of microgel particles at the air/water interface, specular and off-specular X-ray reflectivity (XRR/OSR) allows measurements without any labelling techniques. Herein we investigate the vertical and lateral structure of poly(-isopropylacrylamide) (PNIPAM) microgels (MGs) at the air/water interface and the effect of Langmuir-Blodgett (LB) transfer onto solid substrates. The initial atomic force microscopy (AFM) scans of LB-transferred MGs at the air/solid interface reveal strong lateral 2D hexagonal ordering across a broad range of lateral surface pressures. Notably, for the first time, these results were confirmed by OSR, demonstrating the existence of the long-range hexagonal ordering at low and intermediate surface pressures. For conditions and upon uniaxial compression at the air/water interface, the MG lattice constant decreases non-monotonically. This indicates the formation of domains at low pressures that approach each other and only compress when the surface isotherm reaches a plateau. Comparing the results of and measurements, our study demonstrates a clear transfer effect during the LB-deposition on the lateral ordering of the MGs: the distance between the particles decreased during LB-transfer, and at high pressures ( > 17 mN m) a second distance occurs, indicating small domains with hexagonal internal ordering. The novel surface characterisation approaches debuted here highlight the use of both XRR and OSR to probe the vertical and lateral structure of adsorbed MGs, offering , non-invasive insights without the need for doping or transfer-induced artefacts.

Ionic liquids (IL) are room-temperature molten salts that function as complex fluids with tunable interfacial and bulk properties, making them attractive for applications ranging from electrochemical energy storage to lubrication. In such systems, the viscoelasticity of the electric double layer (EDL) at charged interfaces can strongly influence performance, yet its characterization remains challenging due to the nanometric EDL thickness. Herein, we use quartz crystal microbalance (QCM) to measure changes in the resonant frequency and energy dissipation of a gold-coated quartz crystal upon deposition of IL solutions. Since the gold surface of the QCM is negatively charged at an open-circuit potential, we can estimate the loss modulus of the EDL near the charged surface through a wave propagation model under non-confining conditions. Using 1-butyl-3-methylimidazolium (Bmim)-based ILs with three distinct anions-bis(trifluoromethanesulfonyl)imide (TFSI), trifluoromethanesulfonate (TfO), and tetrafluoroborate (BF), we find that the EDL loss modulus increases sharply with increasing IL concentrations in the low concentration regime, eventually reaching values up to three orders of magnitude higher than that of the bulk solution and saturating at high concentrations. Notably, this concentration-dependent scaling is consistent across the three anion types tested, in contrast to reports for nanoconfined ILs where ion identity markedly affects this behavior. Our results demonstrate that bulk viscoelastic properties can be used to infer the EDL loss modulus under non-confining conditions, providing a practical framework for engineering soft, ion-rich interfaces in electrochemical and tribological systems.

The shape of biological shells, such as cell nuclei, membranes, and lipid vesicles, often deviates from a perfect sphere due to an interplay of complex interactions with a myriad of molecular structures. In particular, semiflexible biopolymers adsorbed to the surfaces of such shells seem to affect their morphological properties. While the effect of a single, long, semiflexible chain is relatively well characterized, the mechanisms by which a high density of such surface-adsorbed polymers can alter the morphology of a spherical, soft confinement, akin to biological shells, remain relatively poorly understood. Here, we use coarse-grained molecular dynamics to explore how surface adsorption of many semiflexible polymers affects the morphology of a pressurized bead-spring network shell, which is spherical in the absence of these polymers. By varying the attraction strength between the semiflexible chains and the shell surface, chain concentration, and the polymerization degree of chains, we demonstrate that strong surface localization of the chains can induce shape distortions and decreased shell size. Conversely, weak localization does not induce significant shape fluctuations, yet nematically ordered phases appear on the surface. Notably, these ordered phases lead to elliptic shell shapes for chains with sizes comparable to or longer than the radius of the confinement when the elastic shell is composed of extensible, harmonic bonds, which may emulate a liquid-like structure. Overall, our findings offer a strategy to control the morphology of synthetic shells by manipulating peripheral localization and length of semiflexible polymers while suggesting a mechanism for non-spherical shapes appearing in some biological systems.

When a drop of liquid is placed on top of a swollen solid, if the liquid is immiscible with the solvent of the swollen solid, the surface tension near the contact line can pull the solvent out from the solid, leading to a phase separation that converts the classical three-phase contact line into a four-phase contact zone. This phase separation can significantly affect the wetting properties of the swollen solid and the effect is known to be time dependent. This paper develops a dynamic osmocapillary model which predicts that the size of the phase separation increases with time, following the scaling relation of . The prediction agrees well with existing experiments.

Nowadays hydrogel microparticles find numerous applications in material science and biological engineering such as drug delivery systems, cell carriers, Droplet microfluidics provides an efficient tool for producing monodisperse microparticles, however, optimization of synthesis conditions remains challenging. Here, we developed a simple and easy-to-use method for visual assessment or quantitative characterization of hydrogel crosslinking inside water-in-oil droplets. It is based on the difference in the merging dynamics of water-in-oil emulsions and crosslinked hydrogel microparticles in an external electric field and is compatible with various designs of microfluidic devices, types of materials and crosslinking mechanisms. Integrating a metal electrode into a microfluidic device with a flow-focusing droplet generator, we investigated how water-in-oil droplet merging occurs and then demonstrated that electrocoalescence can be used for characterization of the polyacrylamide, polyethylene glycol diacrylate and alginate microparticles during their crosslinking. We suggest that implementation of the droplet electrocoalescence for control of hydrogel crosslinking technique paves the way to achieve efficient, stable and reproducible synthesis of hydrogel microparticles, which is highly demanded for biomedical applications.

Nematic layers of DIO held in planar aligning cells are found to exist in a periodic ground state, involving polar and azimuthal director deviations, even in the absence of any external perturbing field. The stripe instability appears definitively in thin cells, over a few °C above the antiferroelectric smectic Z onset point, weakening progressively with increasing temperature. The pattern wave vector lies practically along the normal to the rubbing direction. In 90°-twist cells, two sets of stripes form with their wave vectors dependent on the substrate rubbing directions, evidencing the instability as a surface phenomenon. We propose for its origin a new mechanism that involves only the usual Frank elasticity and the surface electric field generated by adsorption of ions. The elastic energy of the proposed periodic director deformation field is zero, and it results from the gain in dielectric energy due to the surface electric field overcoming the cost of weakened anchoring energy.

Magnetic Janus particles (MJPs) with radially shifted dipoles exhibit a versatile platform for engineering responsive materials through field-directed self-assembly. Motivated by their potential in programmable soft matter, Brownian dynamics simulations are used to systematically investigate how the radial dipolar displacement and the Langevin parameter govern the aggregation pathways and emergent morphologies of MJPs in quasi-two-dimensional environments. We identified six distinct aggregation regimes: three arising under low magnetic fields ( ≲ 10) corresponding to the low-, intermediate-, and high-shift cases, and two emerging at intermediate (10 ≲ ≲ 90) and high magnetic fields ( ≳ 90). These regimes exhibit a rich morphological evolution as increases: from disordered loops (low , low ), islands (low , intermediate ), and worm-like clusters (low , high ), transitioning through chiral and tangled chains (intermediate , intermediate and high ), and culminating in fully aligned chains (intermediate with low , and high for all ). A structure diagram predicted by considering a simple ratio of competing torques () effectively illustrates these transitions and specifies the conditions necessary for structural reorganization. This framework supports the rational design of adaptive colloidal architectures for applications in targeted delivery, soft microrobotics, and reconfigurable magnetic systems. Notably, the universal convergence to a growth exponent of ≈ 0.473 under high magnetic fields ( ≳ 90) reveals a definitive kinetic signature of complete cluster alignment along the field direction, establishing a robust and tunable route to field-induced material organization.

Incorporating hydrophobic associations into hydrophilic networks as energy dissipation units is an efficient strategy to toughen hydrogels. However, the micro-segregated structures often lead to turbid hydrogels with poor optical properties. Here, we report the synthesis of transparent, tough, and fluorescent hydrogels in which tetraphenylethylene (TPE) fluorogens are linked to the network by a polymethylene spacer. The TPE motif and polymethylene spacer form hydrophobic associations, affording the transparent hydrogels with excellent mechanical properties and strong fluorescence. The mechanical properties of the hydrogels can be tuned by the fraction of hydrophobic units, the length of the polymethylene spacer, and the presence of the TPE motif. A rubbery-to-glassy transition is found in poly(12-(4-(1,2,2-triphenylvinyl)phenoxy)dodecyl acrylate--acrylic acid) hydrogels and poly(4-(1,2,2-triphenylvinyl)phenoxy)hexyl acrylate--acrylic acid) hydrogels as the fraction of hydrophobic units increases. The increased glass transition temperatures and apparent activation energies of the hydrogels with longer spacers and the TPE motif indicate a synergistic effect between the hydrophobic polymethylene and TPE motifs. Small- and wide-angle X-ray scattering results show that these tough and fluorescent hydrogels have compact hydrophobic domains with a quasi-lamellar structure. The hydrophobic domains are disrupted during stretching to dissipate energy, accounting for the high toughness of the hydrogels. This study presents a novel strategy to construct tough and fluorescent hydrogels by forming synergistic associations, which should be informative for designing other tough materials with specific functions and applications.

Three peptide amphiphiles based on aromatic amino acids have been successfully synthesized, purified, and thoroughly characterized. These peptides were found to form hydrogels at physiological pH 7.46, exhibiting a unique time-dependent self-shrinking behaviour. Notably, the extent and nature of this self-shrinking varied according to the specific amino acid sequence of each peptide. In addition to this, the hydrogels demonstrated remarkable self-healing abilities and 3D shape-memory properties. To investigate the role of sequence variation, particularly the position of the L-phenylalanine residue, coarse-grained molecular dynamics simulations were employed. These simulations aimed to elucidate how different sequences influence self-assembly into the nanoscale network structures characteristic of the hydrogels. Importantly, the computational findings showed strong agreement with the experimental results, confirming the formation of distinct hydrogel architectures driven by the peptide sequences.

Scaling laws arise and are eulogized across disciplines from natural to social sciences for providing pithy, quantitative, 'scale-free', and 'universal' power law relationships between two variables. On a log-log plot, the power laws display as straight lines, with a slope set by the exponent of the scaling law. In practice, a scaling relationship works only for a limited range, bookended by crossovers to other scaling laws. Leading with Taylor's oft-cited scaling law for the blast radius of an explosion against time, and by collating an unprecedented amount of datasets for laser-induced, chemical and nuclear explosions, we show distinct kinematics arise at the early and late stages. We illustrate that picking objective scales for the two axes using the transitions between regimes leads to the collapse of the data for the two regimes and their crossover, but the third regime is typically not mapped to the master curve. The objective scales permit us to abandon the arbitrarily chosen anthropocentric units of measurement, like feet for length and heart-beat for time, but the decimal system with ten digits (fingers) is still part of the picture. We show a remarkable collapse of all three regimes onto a common master curve occurs if we replace the base 10 by a dimensionless radix that combines the scales from the two crossovers. We also illustrate this approach of radical scaling for capillarity-driven pinching, coalescence and spreading of drops and bubbles, expecting such generalizations will be made for datasets across many disciplines.

Surface alignment of a recently discovered ferroelectric nematic liquid crystal (N) is usually achieved using buffed polymer films, which produce a unidirectional polar alignment of the spontaneous electric polarization. We demonstrate that photosensitive polymer substrates could provide a broader variety of alignment modes. Namely, a polyvinyl cinnamate polymer film irradiated by linearly polarized ultraviolet (UV) light yields two modes of surface orientation of the N polarization: (1) a planar apolar mode, in which the equilibrium N polarization aligns perpendicularly to the polarization of normally impinging UV light; the N polarization adopts either of the two antiparallel states; (2) a planar polar mode, produced by an additional irradiation with obliquely impinging UV light; in this mode, there is only one stable azimuthal direction of polarization in the plane of the substrate. The two modes differ in their response to an electric field. In the planar apolar mode, the polarization can be switched back and forth between two states of equal surface energy. In the planar polar mode, the field-perturbed polarization relaxes back to the single photoinduced "easy axis" once the field is switched off. The versatility of modes and absence of mechanical contact make the photoalignment of N attractive for practical applications.

Binary colloids of two different nanosheet species are promising systems for novel integrated materials because of their multicomponent and multiphase coexistence utilizable in novel smart materials. Among the binary colloids, niobate-clay binary nanosheet colloids are characterized by unusual photochemical functions and phase separation at a mesoscopic (∼several tens of micrometers) scale. The present study clarifies the colloidal state of the clay nanosheets in the mesostructured aqueous binary colloid of hexaniobate and fluorohectorite clay nanosheets by using small-angle neutron scattering (SANS) with the contrast variation technique. Compared to small-angle X-ray scattering (SAXS) that preferentially detects the niobate nanosheets, contrast variation SANS measurements can match out each nanosheet species to detect liquid crystalline ordering of each nanosheet species. The SANS results demonstrate the coexistence of two liquid crystalline phases induced by niobate and clay nanosheets, respectively, in the niobate-clay binary nanosheet colloids.

The jamming onset of particle packings provides an ideal physical state for the comparison of mechanical properties. In this paper, we investigate the effects of size distribution and particle shape on the mechanical response of disordered jammed packings. For packings of bidisperse spheres, both species participate in the force network for the small particle volume fraction ≤ 0.35, boosting the bulk modulus by nearly 60% relative to the monodisperse case. On the other hand, the high rattler fraction induced by some polydispersity generally reduces compared to the monodisperse case. Within the family of superellipsoids and spherocylinders studied, packings of nonspherical particles show higher than that of spheres, with the self-dual ellipsoids achieving the maximum value, where exhibits robust power-law scaling with pressure. Moreover, although shows no direct correlation with packing density, it exhibits a robust linear scaling with the coordination number across different particle shapes. This linear relation persists in polydisperse sphere systems when a volume-weighted coordination number is employed to account for the size disparity. These findings advance our understanding of jamming transitions and facilitate rational granular material design.

The complex physics of self-assembly in colloidal crystals on deformable interfaces and surfaces poses interesting possibilities for the synthesis of new materials. The goal of this article is to address one such aspect and characterize instabilities arising in colloidal crystals assembled on fluid membranes. The colloidal particles are modeled as pair-wise interacting point particles, constrained to lie on a fluid membrane and yet free to reorganize, and the membrane's elastic energy is modeled the Helfrich energy. We find that when a collection of particles is arranged on a planar membrane in some regular fashion - such as a periodic lattice - then the regular configuration admits bifurcations to non-planar configurations. Using the Bloch-wave ansatz for the mode of instabilities, we present a parametric analysis of the boundary between the stable and unstable regimes. We find that instabilities can occur through two distinct kinds of modes, when the parameters belong in certain physically interesting regimes, referred to as long-wavenumber modes (L modes) and short-wavenumber modes (S modes) in the article. We discuss some connections between these results and recent experiments, as well as relationships with the open problem of budding in biomembranes.

Complex coacervates are widely studied in manufacturing, food processing, personal care, and therapeutics. While much research pertinent to coacervates has recently focused on their phase behavior, their glassy dynamics remains largely unexplored. We anticipated, based on a combination of the generalized entropy theory (GET) of the dynamics of glass-forming liquids and recent molecular dynamics simulation studies, that variations in these material's polymer charge density should significantly alter the glass transition temperature () and fragility () because of the known effect of charge on the cohesive energy density of polymer materials. To test this hypothesis, we performed dielectric spectroscopy measurements on model complex coacervate films formed by blending poly-diallyldimethyl ammonium chloride (PDDA) and adenosine triphosphate (ATP). The critical salt concentration () was taken to be a quantitative measure of molecular interaction strength, . The films were vacuum annealed before dielectric measurements were conducted over a wide temperature range extending down to temperatures close to . As anticipated, we find that increasing increases , but progressively decreases . We also find that our coacervate films exhibit high apparent dielectric permittivity (>10) at room temperature for a moderate frequency of 1 kHz, which naturally explains the observed high responsiveness of such materials to even relatively weak electric fields (≈1 V cm). Finally, we show that moisture tends to plasticize the glassy dynamics of these materials, , reduce . These trends are expected to hold rather generally for complex coacervate materials arising in diverse manufacturing and biophysical contexts.

Polymorphic transitions between three hexagonal structures have been observed during the epitaxial growth of colloidal particles when the ratio of particle sizes of the epitaxial and substrate particles was a specific value. These polymorphic transitions were examined by performing Brownian dynamics simulations. In both the experiment and simulations, three types of hexagonal structures formed in the first epitaxial layer when the epitaxial particle size was chosen appropriately. The growth pathways of the epitaxial layers and final structures depend on the growth conditions. The key factors determining the growth pathway and final structure of the epitaxial layers are the interaction between the substrate and first epitaxial layer, the difference in the ease of formation of the second layers due to the unevenness of the first epitaxial layer, and the rate of epitaxial particle supply on the substrate.

To explore the physicochemical hydrodynamics of phase-separating ternary liquids ("Ouzo-type"), a binary oil-ethanol mixture is introduced into a co-flowing stream of water. Oil droplets nucleate at the interface between the two liquids, leading to a larger oil droplet interacting with the ethanol-rich jet. Although buoyancy forces and hydrodynamic drag forces push the droplet in downstream direction, we observe an upstream motion. Using computational fluid dynamics simulations of a simplified model system, we identify the nucleation zone for oil droplets and uncover Marangoni forces to be responsible for the upstream motion of the droplet. A semi-analytical model allows us to identify the key parameters governing this effect. A general conclusion is that Marangoni stresses can reverse the motion of droplets through channels, where the surrounding liquid is a multi-component mixture. The insights from this work are not only relevant for channel flow, but more generally, for the physicochemical hydrodynamics of multiphase, multi-component systems.

Single-stranded DNA molecules modified with cholesterol functional groups are physically tethered to silica nanoparticles (diameter 25 nm) that are encapsulated in a lipid bilayer. Such tethering increases the azimuthal mobility of the DNA molecules across the nanoparticle surface and enables nonspecific bonding, eliminating the need for specialized surface chemistries (such as silane or thiol ligands). To induce assembly, double-stranded DNA 'bridge' molecules are then added with complementary nucleotides to the DNA 'anchor' molecules that are physically tethered to the lipids on the surface of the particles. Assembly is observed to occur at room temperature and without the need for temperature annealing. Using automated liquid handling tools, assemblies are created in high throughput and rapidly characterized using SAXS. It is determined that the relative concentration of DNA-to-silica and the ionic strength of the solution are important parameters that affect the resulting assembly. Analysis of SAXS data is performed using coarse-grained particle dynamics simulations. The results support the spontaneous formation of semi-crystalline particle assemblies by particle condensation, where the interparticle distance is tuned by the sequence of the DNA 'bridge' used to link the particles. Crystallinity analysis performed on the resulting simulations, optimized to match SAXS observations, suggest that particle clusters display increased crystallinity in the center of the clusters, but their maximum size remains relatively small (sub-micron) before settling occurs, which limits the extent of crystallization.

Micellization is commonly described as a collective response driven by the hydrophobic effect. Here we propose and study a topological Ising model that abstracts this effect as a solvent-exclusion constraint defined purely by local connectivity. On a square lattice with binary occupancy (amphiphiles/water), we characterize neighborhood by a topological kernel of radius and metric (Chebyshev or Manhattan). A water site becomes "restricted" when the local overlap with amphiphiles, computed convolution with the kernel, exceeds a fixed threshold. The system energy is = ; we set = 1 by design, working in dimensionless units that prevent interpreting as carrying any metric information. Dynamics are explored with Metropolis updates at temperature . Control parameters are amphiphile density , temperature , the metric, and . As an order parameter we use /, the fraction of amphiphiles in the largest connected cluster. In the surveyed ranges we observe, for more connective kernels (, Chebyshev with ≥ 3), the emergence of a giant component in finite regions of (, ), while less connective configurations (, Manhattan with = 1) do not aggregate in the same window. These results support the view that micellization, in this framework, is a connectivity transition governed by the topology of local interactions rather than by explicit metric scales. We discuss implications and routes for quantitative comparisons with experiments and more detailed simulations.

The growing energy crisis has intensified the focus on green energy, sparking widespread interest in aqueous zinc-ion batteries. However, their development has been hindered by issues in the zinc anode. Here, Ca/Zn alginate hydrogel electrolyte was designed to effectively suppress dendritic growth and parasitic side reactions. The Ca primary cross-linking provides a regular "egg-box" network framework for fast ion transport, whereas secondary cross-linking with Zn creates a denser, interpenetrating network with calcium, thereby enhancing the hydrogel's mechanical strength. Furthermore, the abundant -OH and -COO groups on the alginate chains formed hydrogen bonds with HO, which reduced water activity. Meanwhile, the abundant -OH and -COOH groups on the alginate chains formed hydrogen bonds/coordination with HO/Zn, reducing the activity of HO and strengthening the ion confinement effect. Therefore, the Zn/SCZ/Zn symmetric cell achieved stable cycling for over 900 hours at 2 mA cm and 2 mAh cm, while the Zn/SCZ/MnO battery retained 62.03% of its capacity after 700 cycles. This Ca/Zn dual-ion crosslinking strategy for the alginate hydrogel electrolyte offers a novel approach to address the limitations of conventional aqueous electrolytes.