Soft Matter最新文献

{"title":"Unraveling molecular mechanisms of aging dynamics in the Kob–Andersen model: the role of free volume†","authors":"Yifan Yang, Yuyuan Lu, Yaozhang Yang, Xia Wang and Lijia An","doi":"10.1039/D5SM00447K","DOIUrl":"10.1039/D5SM00447K","url":null,"abstract":"<p >This study elucidates the role of free volume in the aging dynamics of the Kob–Andersen (KA) model through temperature cycling experiments. By examining the relationship between free volume and key phenomena such as aging, rejuvenation, and memory effects, we clarify how free volume influences the aging process in this system. Our results reveal a strong correlation between local free volume and the fraction of fast-moving particles, both of which significantly affect the dynamic susceptibility. This indicates that aging dynamics are largely governed by rapidly relaxing particles residing in regions of larger local free volume. Notably, we find no evidence of rejuvenation effects, in contrast to previous reports on the Weeks–Chandler–Andersen (WCA) system; however, memory effects are observed and attributed to minimal local structural rearrangements during aging. Taken together, these findings contribute to a more detailed molecular-level understanding of aging dynamics and provide valuable perspectives on the complex behavior of glassy systems.</p>","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" 27","pages":" 5542-5552"},"PeriodicalIF":2.9,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144332106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Liquid drop impact on granular beds: the influence of drop inertia and grain size","authors":"Alexandre Pontier, Sarah Blosse, Sylvain Viroulet and Laurent Lacaze","doi":"10.1039/D4SM00917G","DOIUrl":"10.1039/D4SM00917G","url":null,"abstract":"<p >This paper explores crater formation resulting from the impact of a liquid drop on a densely packed granular bed composed of lightweight polystyrene beads. Several regimes based on the drop impact velocity <em>v</em> and diameter <em>D</em>, and the grain diameter <em>d</em><small>_g</small> are identified. These regimes are discussed in terms of several dimensionless numbers, including a Froude number Fr, which compares the droplet's kinetic energy to its potential energy at impact, the Weber number We, which compares the inertial to capillary forces, and the size ratio <em>d</em><small>_g</small>/<em>D</em>. At low We, Fr, and <em>d</em><small>_g</small>/<em>D</em>, the dimensionless crater diameter <em>D</em><small>_max</small>/<em>D</em> follows a power-law scaling as We<small>^1/4</small>, consistent with previous studies on droplet impacts on granular surfaces, where the crater size reflects the maximum droplet spreading observed on a solid surface. This situation is thus analysed using a so-called signature approach. In this situation, the crater size is also shown to quantitatively depend on <em>d</em><small>_g</small>/<em>D</em>. When We exceeds a critical value We<small>_c</small>(<em>d</em><small>_g</small>/<em>D</em>), the scaling deviates from We<small>^1/4</small> and the crater size depends mainly on <em>d</em><small>_g</small>/<em>D</em>. This transition is discussed in connection with the onset of droplet splashing. For larger <em>d</em><small>_g</small>/<em>D</em>, a different power-law scaling emerges with an exponent smaller than 1/4, regardless of the value of Fr or We, and the splash transition no longer occurs under these conditions. This is consistent with other studies, highlighting the significant amount of energy transfer in crater formation, therefore referred to as the energetic approach. Overall, the final crater size is found to depend strongly on <em>d</em><small>_g</small>/<em>D</em> among the droplet impact characteristics. To unify part of these observations, the role of local dissipation due to grain contact friction during crater formation is incorporated. This leads to the definition of a new dimensionless number <img>, which combines the effects of grain-to-drop size ratio <em>d</em><small>_g</small>/<em>D</em> and droplet inertia (<em>via</em> Fr). This parameter enables the collapse of <em>D</em><small>_max</small>/<em>D</em> data onto a single curve for the range of parameters investigated in this study.</p>","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" 29","pages":" 5935-5946"},"PeriodicalIF":2.9,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2025/sm/d4sm00917g?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144537510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Curvature-dependent propulsion of elastic flagella.","authors":"Taylor E Greenwood, Luis Felipe Córdoba, Jian Teng, Saebom Lee, Genevieve Dare, Ebru Demir, On Shun Pak, Yong Lin Kong","doi":"10.1039/d4sm01548g","DOIUrl":"https://doi.org/10.1039/d4sm01548g","url":null,"abstract":"<p><p>Soft robotic swimmers that can mimic the flagella-powered locomotion of micro-organisms are of significant interest in a broad range of applications. However, realising micro-organisms' dexterity in soft robots remains challenging without an effective mechanism to achieve bidirectional propulsion in low Reynolds numbers. Here, inspired by recent theoretical studies that suggest the possibility of intrinsically curved elastic flagella to achieve bidirectional propulsion, we experimentally investigate the propulsion behaviour of elastic artificial flagella with uniform intrinsic curvature, actuated by transverse oscillations at Re < 0.1. Our results reveal that the flagella's curvature influences the propulsion direction and magnitude, suggesting a transition between positive and negative propulsion when the flagella's central angle in the stress-free state (<i>θ</i>₀) is between 60° and 90° at Sp = 1.5 and 1.8. We also investigate the relationship between the propulsion force and flagella oscillation with numerical simulations. These findings suggest the potential of on-demand curvature modulation during active oscillation to achieve bidirectional propulsion, enhancing the dexterity in flagella-driven artificial swimmers for a broad range of applications in microscale systems.</p>","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144323909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Interpretable machine-learning enhanced parametrization methodology for Pluronics–water mixtures in DPD simulations","authors":"Nunzia Lauriello, Deekshith Naidu Ponnana, Zhan Ma, Karel Šindelka, Antonio Buffo, Gianluca Boccardo, Daniele Marchisio and Wenxiao Pan","doi":"10.1039/D5SM00291E","DOIUrl":"10.1039/D5SM00291E","url":null,"abstract":"<p >Dissipative particle dynamics (DPD) is an incredibly powerful tool for simulating the behavior of structured fluids. However, identifying the appropriate model parameters to accurately replicate physical properties remains a challenge. This study showcases the benefits of integrating machine learning techniques into the top-down parameterization of Pluronic systems. The proposed workflow outlines a data-driven approach to accurately determine model parameters tailored to various Pluronic systems. Gaussian process regression (GPR)-based surrogate models effectively replicate the results of DPD simulations, delivering faster responses that streamline parameter optimization and enable the calibration of Pluronic systems against experimental data. Although DPD simulations provide valuable insight, their high computational cost, due to extensive simulations and post-processing, presents a challenge. The GPR-based surrogate model addresses this by modeling the relationships between input parameters and output properties. SHAP (SHapley additive exPlanations) analysis enhances model interpretability, providing deeper insights into the relationships and causal mechanisms between the input parameters and the predicted properties. The combination of GPR and SHAP analysis provides an interpretable machine learning approach, enabling a more efficient optimization process and reducing the need for exhaustive simulations. This work lays a foundation for generalizing the parameterization process across Pluronic systems and conditions, such as varying temperatures, by incorporating additional DPD model input parameters.</p>","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" 29","pages":" 5833-5851"},"PeriodicalIF":2.9,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144323911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"SANS and rheology of elongated SDS–DDAO mixed micelles near the phase boundary†","authors":"Luis M. G. Torquato, Gunjan Tyagi, Zain Ahmad, Liva Donina, Najet Mahmoudi, Rebecca Fong, Paul F. Luckham and João T. Cabral","doi":"10.1039/D5SM00437C","DOIUrl":"10.1039/D5SM00437C","url":null,"abstract":"<p >We examine the micellar phase of sodium dodecyl sulphate (SDS) and <em>N</em>,<em>N</em>-dimethyldodecylamine <em>N</em>-oxide (DDAO) in water, a synergistic anionic/amphoteric mixed surfactant system, in the vicinity of the phase boundary, employing small angle neutron scattering (SANS) and rheology. Specifically, we investigate the role of the SDS : DDAO mixing ratio at a fixed concentration at room temperature. While neat SDS and DDAO form near-spherical micelles with radius ≈20 Å, these elongate into prolates with ≈90 Å polar axis, at intermediate 60–70% mol DDAO ratios. Micellar charge remains largely invariant with a surfactant ratio up to ≤80% DDAO, decreasing thereafter towards uncharged, neat DDAO, except for a large increase in charge, and up to 4 orders of magnitude in solution viscosity (from ≈1 to in excess of 10<small>⁴</small> mPa s), accompanied by scattering anisotropy, at those intermediate ratios and in 500 mM solutions. A strong correlation is found between solution viscosity and micellar dimensions (and structure factor peak) in the vicinity of the phase boundary.</p>","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" 27","pages":" 5494-5502"},"PeriodicalIF":2.9,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2025/sm/d5sm00437c?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144315613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamics of a bottom-heavy Janus particle near a wall under shear flow†","authors":"Zohreh Jalilvand, Daniele Notarmuzi, Ubaldo M. Córdova-Figueroa, Emanuela Bianchi and Ilona Kretzschmar","doi":"10.1039/D5SM00229J","DOIUrl":"10.1039/D5SM00229J","url":null,"abstract":"<p >In this study, Brownian dynamics simulations are implemented to investigate the motion of a bottom-heavy Janus particle near a wall under varying shear flow conditions and at small Péclet (Pe) numbers. The stochastic motion of the Janus particle impacted by surface forces is described using a set of coupled Langevin equations that takes into account the Janus particle orientation. Interactions arising from surface potentials are found to depend on the separation distance between the Janus particle and the wall, the properties of the surfaces involved, and the thickness of the Janus particle cap. When shear flow is introduced in the system, the dynamical behavior of the Janus particle is also governed by the strain rate. Furthermore, the effect of friction on the dynamical behavior of the Janus particle under shear flow is investigated and reveals that the rotational motion of the Janus particle slows down slightly when the particle is close to the surface. In summary, we demonstrate the ability to utilize Brownian dynamics simulations to capture the rich dynamical behavior of a bottom-heavy Janus particle near a wall and under a range of shear flow conditions, cap thicknesses, and surface charges.</p>","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" 28","pages":" 5773-5784"},"PeriodicalIF":2.9,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12198726/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144493184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hacktive matter: data-driven discovery through hackathon-based cross-disciplinary coding†","authors":"Megan T. Valentine and Rae M. Robertson-Anderson","doi":"10.1039/D5SM00401B","DOIUrl":"10.1039/D5SM00401B","url":null,"abstract":"<p >The past decade has seen unprecedented growth in active matter and autonomous biomaterials research, yielding diverse classes of materials capable of flowing, contracting, bundling, de-mixing, and coalescing. These innovations promise revolutionary applications such as self-healing infrastructure, dynamic prosthetics, and self-sensing tissue implants. However, inconsistencies in metrics, definitions, and analysis algorithms across research groups, as well as the high-dimensionality of experimental data streams, has hindered the identification of performance intersections among such dynamic systems. Progress in this arena demands multi-disciplinary team approaches to discovery, with scaffolded training and cross-pollination of ideas, and requires new methods for learning and collaboration. To address this challenge, we have developed a hackathon platform to train future scientists and engineers in ‘big data’, interdisciplinary collaboration, and community coding; and to design and beta-test high-throughput (HTP) biomaterials analysis software and workflows. We enforce a flat hierarchy, pairing participants ranging from high school students to faculty with varied experiences and skills to collectively contribute to data acquisition and processing, ideation, coding, testing and dissemination. With clearly-defined goals and deliverables, participants achieve success through a series of tutorials, small group coding sessions, facilitated breakouts, and large group report-outs and discussions. These modules facilitate efficient iterative algorithm development and optimization; strengthen community and collaboration skills; and establish teams, benchmarks, and community standards for continued productive work. Our hackathons provide a powerful model for the soft matter community to educate and train students and collaborators in cutting edge data-driven analysis, which is critical for future innovation in complex materials research.</p>","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" 27","pages":" 5381-5392"},"PeriodicalIF":2.9,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144482627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"X-ray fluorescence standing wave study of the interaction of the antimicrobial peptide indolicidin with a supported model membrane†","authors":"Gobind Basnet, Jonathan Maloney, Jyotsana Lal, Elizabeth Gaillard, Denis T. Keane, Evguenia A. Karapetrova, Raymond Conley and Laurence Lurio","doi":"10.1039/D5SM00257E","DOIUrl":"10.1039/D5SM00257E","url":null,"abstract":"<p >Indolicidin, a cationic antimicrobial peptide, interacts with lipid bilayers through electrostatic and hydrophobic interactions, disrupting microbial membranes. We investigated the depth-dependent localization of gold-nanoparticle-labeled indolicidin in a supported model membrane using X-ray fluorescence standing wave (SWXF) analysis. Liposomes composed of DMPC and DMPG were incubated with indolicidin labeled at its C-terminus with a 1.8 nm gold nanoparticle, then deposited onto a Si/Mo multilayer substrate <em>via</em> vesicle bursting. SWXF measurements revealed that at low peptide incubation concentrations (2–5 μM), gold-nanoparticle-labeled indolicidin remains primarily associated with the bilayer's outer leaflet. At higher concentrations (10 μM), the peptide penetrates deeper into the bilayer, with the labeled C-terminal region either localizing near the membrane's hydrophobic core or inducing membrane breakup. These findings suggest a concentration-dependent insertion mechanism.</p>","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" 28","pages":" 5785-5792"},"PeriodicalIF":2.9,"publicationDate":"2025-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144493188","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Long-range order in two-dimensional systems with fluctuating active stresses†","authors":"Yann-Edwin Keta and Silke Henkes","doi":"10.1039/D5SM00208G","DOIUrl":"10.1039/D5SM00208G","url":null,"abstract":"<p >In two-dimensional tissues, such as developing germ layers, pair-wise forces (or active stresses) arise from the contractile activity of the cytoskeleton, with dissipation provided by the three-dimensional surroundings. We show analytically how these pair-wise stochastic forces, unlike the particle-wise independent fluctuating forces usually considered in active matter systems, produce conserved centre-of-mass dynamics and so are able to damp large-wavelength displacement fluctuations in elastic systems. A consequence of this is the stabilisation of long-range translational order in two dimensions, in clear violation of the celebrated Mermin–Wagner theorem, and the emergence of hyperuniformity with a structure factor <em>S</em>(<em>q</em>) ∼ <em>q</em><small>²</small> in the <em>q</em> → 0 limit. We then introduce two numerical cell tissue models which feature these pair-wise active forces. First a vertex model, in which the cell tissue is represented by a tiling of polygons where the edges represent cell junctions and with activity provided by stochastic junctional contractions. Second an active disk model, derived from active Brownian particles, but with pairs of equal and opposite stochastic forces between particles. We study the melting transition of these models and find a first-order phase transition between an ordered and a disordered phase in the disk model with active stresses. We confirm our analytical prediction of long-range order in both numerical models and show that hyperuniformity survives in the disordered phase, thus constituting a hidden order in our model tissue. Owing to the generality of this mechanism, we expect our results to be testable in living organisms, and to also apply to artificial systems with the same symmetry.</p>","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" 28","pages":" 5710-5719"},"PeriodicalIF":2.9,"publicationDate":"2025-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2025/sm/d5sm00208g?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144482628","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Note on two-point mean square displacement","authors":"Naoya Katayama and Takahiro Sakaue","doi":"10.1039/D5SM00555H","DOIUrl":"10.1039/D5SM00555H","url":null,"abstract":"<p >When probe molecules of interest are embedded in a substrate or aggregate under stochastic motion, one needs to rely on the so-called two-point mean square displacement (MSD) measurement to extract the intrinsic mobility of the probes. We discuss two versions, based on the time series of relative vector or distance between two probes, and summarize their basic properties compared to the standard MSD. We also propose a way to extract (i) the non-Gaussianity in the displacement statistics and (ii) the motional correlation between probes from the two-point MSD. The results are presented not only for independent probes, but also for intramolecular probes within a long polymer, which could be useful in quantifying the dynamics of chromatin loci in a living cell nucleus.</p>","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" 29","pages":" 5871-5882"},"PeriodicalIF":2.9,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144504266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}