Soft Matter最新文献

Terrestrial mammals are constantly beset by insects, and the ear is a vulnerable point of entry. Unlike other body orifices that produce fluids such as mucus or tears, the ear appears defenseless. How does it stop invaders? We hypothesize that earwax acts as a slick barrier that prevents insects from crawling into the ear. In this combined experimental and theoretical study, we show that earwax is both slick and adhesive. Ants have difficulty climbing earwax-coated surfaces and cleaning earwax from their bodies. These phenomena are due to the hydrophilic, porous, and viscoelastic properties of earwax, which we study using microscopy, rheology, experiments with ants, and fabrication of arti earwax. We also demonstrate that earwax's aging renders it brittle, facilitating self-removal over a 10-week time scale. This study may be of use to designers of eco-friendly barriers for insects.

Inspired by the conformational rearrangements of G-protein-coupled receptors (GPCRs) during signal transduction in the human olfactory system, this study proposes and validates a molecular discrimination strategy based on packing mode transitions of organic supramolecular aggregates. We constructed four supramolecular aggregates using naphthalene diimide (NDI) derivatives as core building blocks. These aggregates enabled the discrimination of aliphatic amines, aromatic amines, and structurally similar alkaloids, including nicotine and cotinine. Our results demonstrate that subtle differences in molecular structure can induce a reduction in internal packing density and molecular order within the aggregates, and these packing changes are transduced as shifts in spectroscopic signals and variations in spectral intensity. Molecular dynamics simulations further reveal that steric hindrance and electrostatic interactions play key roles in modulating the packing modes of the aggregates, providing molecular-level support for the experimental observations. This work validates the feasibility of using structural responses of supramolecular aggregates for molecular discrimination and offers new experimental and theoretical perspectives on the structural behavior of organic aggregates upon chemical perturbation.

A Lieb lattice of ferromagnetic nematic liquid-crystal elements yields a sublattice-programmable acoustic response, switched on or off by the drive geometry rather than enhanced attenuation. The central result is a point-group-protected drive-selection rule: at the Brillouin-zone center, the B/C-antisymmetric drive projects entirely onto the B₁ irrep of the C_4v little co-group while the uniform and A-only drives contain no B₁ component, so the corresponding drive overlaps η_flat = 1, 0, 0 are exact symmetry consequences, independent of the range of the intersite coupling. Two independent features of the Lieb sublattice structure enable the wider construction. First, the bipartite chiral symmetry pins a zero-eigenvalue mode whose eigenvector has vanishing amplitude on the corner sublattice, making the associated collective channel insensitive to uniform corner-sublattice detuning. Second, when the on-site frequencies and couplings are sublattice-symmetric, the Lieb band index is conserved and the flat magnetic channel hybridizes only with the flat acoustic channel, so the acoustic loss feature at the single-site frequency ω_m(H) is sourced by the flat-channel overlap of the driving field. An interdigitated transducer with oppositely biased combs on the B- and C-edge sublattices maximizes this overlap at Γ and gives the largest Brillouin-zone-averaged overlap among the drive geometries considered; a uniform drive suppresses it. We quantify the selection by an integrated contrast _sel ≈ 10. We further show that a direct B-C hopping generated by dipolar coupling lifts the flat band and reduces the global band-index-conservation selection rule away from Γ, but does not compromise the C_4v-protected drive gating at Γ; realizing the stronger full-Brillouin-zone flat-channel calibration would require engineered short-range interactions that reduce the effective B-C coupling, and an elastic/anchoring contribution is one possible, but presently unverified, route. The Lieb geometry selects a symmetry-filtered acoustic function distinct from the broad, integrated response of frustrated hexagonal flat-band lattices.

Liquid crystalline elastomers (LCEs) are soft materials capable of large, reversible deformations in response to external stimuli, making them promising alternatives to rigid actuators where compliance and untethered motion are crucial. However, adoption of LCEs in real-world systems has been hindered by the lack of practical modeling techniques that describe their functional behavior. Here, we present an analytical continuum framework based on decomposition of the actuation and elastic strains. Paired with existing hyperelastic models, this decomposition yields closed-form constitutive expressions which describe LCE behavior over a broad range of operating conditions. We experimentally validate the framework by showing it successfully predicts the stress state of an LCE across a variety of actuation sequences with low bias and error, indicating path independence for processes where elasticity dominates behavior. We further demonstrate the framework's flexibility by applying it to LCE fibers of different chemistry, and to a fiber having a complex hierarchical architecture; a capability crucial to employing LCE actuators in practical systems. Finally, we illustrate the utility of the resulting closed-form solutions through two design applications: quantitatively determining the coefficient of friction for a low-friction material, and a qualitative procedure for designing an LCE-actuated bistable mechanism. This work provides designers and researchers in soft robotics, microactuators, and compliant systems with a practical, rapidly deployable framework for characterizing and comparing thermoactive soft actuators.

Quantitative comparison between molecular simulations and experimental characterization is often complicated by systematic differences in accessible timescales and control parameters, such that exact matching in absolute units is not generally expected. We introduce a series alignment framework that enables order-preserving, quantitative matching between simulated and experimental observables without requiring one-to-one correspondence in time or temperature. The method formulates the comparison as a global optimization problem over a pairwise distance matrix and identifies an optimal monotonic mapping using dynamic programming. We demonstrate the approach in two case studies: quasi-elastic neutron scattering (QENS) of hydrated lysozyme aligned with molecular dynamics simulations across a range of temperatures and time-resolved small angle X-ray scattering (SAXS) and dynamic light scattering (DLS) measurements of nanoparticle assembly aligned with coarse-grained simulations. In both cases, the alignment reveals systematic offsets between experimental and simulated conditions while preserving physically meaningful trends. This work establishes series alignment as a general framework for integrating simulations with experimental characterization data.

Diabetic chronic wounds which often lead to amputation remain a significant unresolved challenge in clinical practice, posing serious risks to patient health and survival. Existing clinical treatments such as topical administration, traditional dressings and debridement are often inadequate to address the complex pathological microenvironment (chronic inflammation, oxidative stress, etc.) of diabetic chronic wounds, resulting in long treatment cycles and poor outcomes for patients. To address the key pathological factors that impede wound healing, a functional hydrogel dressing was developed in this study using natural polyphenol tannic acid (TA) and biocompatible polyvinyl alcohol (PVA), and aldehyde phenylboronic acid (FPBA) and cyanophenylboronic acid (CPBA) as small molecule crosslinkers. The polyphenol-based hydrogel exhibited strong tissue adhesion, ensuring stable adherence to the wound site after application, thereby preventing infection and mechanical re-injury. And the G-PT hydrogel loaded with TA markedly reduced reactive oxygen species (ROS) production and effectively inhibited DNA damage. Meanwhile, they reduced the levels of early inflammatory factors IL-1β, IL-6 and TNF-α, promoted the polarization of macrophages toward an anti-inflammatory phenotype. In vitro and in vivo evaluations demonstrated that the hydrogel significantly promoted the healing of both acute skin incisions and chronic diabetic wounds by mitigating oxidative stress and regulating macrophage polarization. These findings highlight the therapeutic potential of this multifunctional hydrogel dressing as a promising strategy for treating diabetic wounds.

Fork-shaped diffraction gratings generate optical vortices, i.e., light fields with helical wavefronts. To fabricate such a grating, we focus here on the periodic deformation induced near the phase transition between the nematic and smectic A liquid-crystalline phases. Although the periodic structure typically appears over a temperature range of only ∼0.1 K, which is too narrow for practical use as a grating, we show that this range can be extended to several kelvins by using a reentrant-type nematic liquid crystal. Moreover, by introducing a sandwich cell with a step in the substrate, we successfully create edge dislocations in the periodic pattern owing to the mismatch in its period across the step. Upon illuminating a dislocation with laser light, optical vortices are observed in the first-order diffracted beams, whose intensity distributions strongly depend on the incident polarisation. The resulting dislocations thus function as polarisation-sensitive fork-shaped gratings.

DNA origami is a powerful method to achieve nanoscale folded structures. DNA origami is typically employed to create precisely and tightly folded objects often in small quantities and studied at single molecule scale. Here, we use the DNA origami method to design and fold polymers with complex topologies, and study their rheology and viscoelastic properties in dense conditions. First, we designed and purified topologically distinct DNA nanostructures - linear, circular, and "tadpole" polymers - to evaluate how polymer architecture influences entanglement and rheology. Despite their distinct topologies, we observe that all constructs obeyed universal rheological scalings, likely due to their short length. However, upon thermal annealing in the bulk, the DNA polymers displayed significantly different behaviours. Our results suggest that DNA polymers could be used to engineer thermoresponsive behaviours in complex fluids by introducing reversible and topology-dependent crosslinking.

Multivalent adhesion between ligand-functionalized nanocarriers and cell-surface receptors underlies targeted drug delivery, yet how the structure of flexible carriers regulates binding independently of stiffness remains poorly understood. We use a multiscale statistical mechanics-based framework coupling a deformable-membrane continuum model to coarse-grained models of flexible nanocarriers, ligands, and receptors. Monte Carlo simulations quantify multivalency and resolve binding free energies into enthalpic and entropic contributions. We compare star and linear architectures, subdivision of a fixed ligand budget among multiple carriers, and contour lengths across receptor densities and membrane excess areas. Bond number is receptor-limited at low receptor density and ligand-limited at high density, yielding similar multivalency among designs. Carrier structure instead controls the organization and thermodynamic quality of comparable bond populations through enthalpy-entropy compensation, with receptor translational entropy as the dominant penalty. Linear nanocarriers bind more favorably than star nanocarriers at matched stiffness and multivalency because they incur a smaller collective configurational penalty. Ligand-budget subdivision produces a nonmonotonic response: at high receptor density, the single-carrier system is most favorable and the two-carrier system least favorable because of entropic penalties and weaker receptor-ligand enthalpic stabilization. Contour length produces a weaker receptor-density-dependent crossover: shorter carriers are favored at low receptor density, longer carriers at intermediate density, and their binding free energies converge after ligand saturation. Membrane excess area modulates these balances without imposing a universal ordering. Similar bond numbers can therefore conceal substantial differences in adhesion free energy, providing design principles for matching carrier structure and ligand organization to receptor expression and membrane mechanics.

Hydrogels are often used as reservoirs for chemicals such as drugs or soil treatments, but they can release their payload much too quickly as they dry out or as solute simply diffuses through the water in the gel. It is known that doping gels with oil droplets, creating a material known as an 'emulgel', can trap solute and slow this release, but quantifying this effect is challenging. In this paper, we introduce a new approach to deduce the effective transport properties of an inhomogeneous porous medium comprising two distinct solvent phases which interact with a solute species in different ways. We then show that a rigorous mathematical approach built on the separation of timescales between bulk transport and solute trapping can give an expression for the effective diffusivity as a function of the amount of oil present and its distribution, outlining the application of these composite materials to systems delivering beneficial agents for pharmaceutical and agricultural purposes.