Soft Matter最新文献_第2页

How to estimate the surface coverage of polymer grafted planar substrates and spherical nanoparticles.

IF 2.9 3区化学

Soft Matter Pub Date : 2025-03-27 DOI: 10.1039/d5sm00005j

Cheng-Wu Li, Holger Merlitz, Jens-Uwe Sommer

引用次数: 0

The role of substrate mechanics in osmotic biofilm spreading.

IF 2.9 3区化学

Soft Matter Pub Date : 2025-03-27 DOI: 10.1039/d4sm01463d

Anthony Pietz, Karin John, Uwe Thiele

{"title":"The role of substrate mechanics in osmotic biofilm spreading.","authors":"Anthony Pietz, Karin John, Uwe Thiele","doi":"10.1039/d4sm01463d","DOIUrl":"https://doi.org/10.1039/d4sm01463d","url":null,"abstract":"Bacteria invade surfaces by forming dense colonies encased in a polymer matrix. Successful settlement of founder bacteria, early microcolony development and later macroscopic spreading of these biofilms on surfaces rely on complex physical mechanisms. Recent data show that on soft hydrogels, substrate rigidity is an important determinant for biofilm initiation and spreading, through mostly unknown mechanisms. Using a thermodynamically consistent thin-film approach for suspensions on soft elastic surfaces supplemented with biomass production we investigate in silico the role of substrate softness in the osmotic spreading of biofilms. We show that on soft substrates with an imposed osmotic pressure spreading is considerably slowed down and may be completely halted depending on the biomass production rate. We find that the critical slowing down of biofilm spreading on soft surfaces is caused by a reduced osmotic influx of solvent into the biofilm at the edges, which results from the thermodynamic coupling between substrate deformation and interfacial forces. By linking substrate osmotic pressure and mechanical softness through scaling laws, our simple model semi-quantitatively captures a range of experimentally observed biofilm spreading dynamics on hydrogels with different architectures, underscoring the importance of inherent substrate properties in the spreading process.","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143717716","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}

引用次数: 0

Sub-Newtonian coalescence dynamics in shear-thickening non-Brownian colloidal droplets.

IF 2.9 3区化学

Soft Matter Pub Date : 2025-03-27 DOI: 10.1039/d4sm01389a

M V R Sudheer, Sarath Chandra Varma, Aloke Kumar, Udita U Ghosh

{"title":"Sub-Newtonian coalescence dynamics in shear-thickening non-Brownian colloidal droplets.","authors":"M V R Sudheer, Sarath Chandra Varma, Aloke Kumar, Udita U Ghosh","doi":"10.1039/d4sm01389a","DOIUrl":"https://doi.org/10.1039/d4sm01389a","url":null,"abstract":"Recent investigations into coalescence dynamics of complex fluid droplets revealed the existence of sub-Newtonian behaviour in polymeric fluids (elastic and shear thinning). We hypothesize that such delayed coalescence or sub-Newtonian coalescence dynamics may be extended to the general class of shear thickening fluids. To investigate this, droplets of aqueous corn-starch suspensions were chosen and their coalescence in the sessile-pendant configuration was probed by real-time high-speed imaging. Temporal evolution of the neck (growth) during coalescence was quantified as a function of suspended particle weight fraction, ϕw. The necking behavior was found to evolve as the power-law relation, R = atb, where R is the neck radius, with exponent b ≤ 0.5, implying that it is a subset of the generic sub-Newtonian coalescence. Furthermore, the coalescence dynamics could be demarcated into two distinct regimes, b ∼ 0.5 and b < 0.5, where the emergence of visco-elastic pinch-off response was observed in the latter regime. The particle fraction demarcating these regimes, designated as the critical particle weight fraction, ϕw ∼ ϕc > 0.35, also coincides with the existence of 'jamming' and 'flowing' regions within the neck during viscoelastic pinch-off of cornstarch suspensions (Roché et al., Phys. Rev. Lett., 2011, 107, 134503). We also propose a simplistic theoretical model that captures the observed delay in coalescence dynamics implicitly through altered suspension viscosity stemming from increased particle content.","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143717714","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}

引用次数: 0

Nonlinear behavior of stochastic athermal fiber networks with elastic-plastic fibers.

IF 2.9 3区化学

Soft Matter Pub Date : 2025-03-26 DOI: 10.1039/d4sm01427h

Syed N Amjad, Nishan Parvez, Catalin R Picu

{"title":"Nonlinear behavior of stochastic athermal fiber networks with elastic-plastic fibers.","authors":"Syed N Amjad, Nishan Parvez, Catalin R Picu","doi":"10.1039/d4sm01427h","DOIUrl":"https://doi.org/10.1039/d4sm01427h","url":null,"abstract":"Stochastic fiber networks form the structural component of network materials, which are broadly encountered in engineering and biology. Apparent elastic-plastic behavior, characterized by a yield point and softening at larger strains, is observed in some of these materials. A range of mechanisms, some of which being unrelated to fiber plasticity, may cause this behavior. In this work we investigate network plasticity caused by the plastic deformation of fibers and develop a comprehensive perspective on its relationship with network structural parameters. We determine the scaling of the yield stress and yield strain with network parameters emphasizing differences between the affine and non-affine deformation regimes. The non-linear response of the network is more complex when fiber plasticity takes place than in the purely elastic case. We describe four non-linear regimes and their dependence on network parameters. Further, we evaluate the dissipation and residual strains resulting upon loading-unloading cycles for a variety of networks and discuss design strategies for maximizing energy dissipation. Finally, we provide guidelines for the interpretation of experimental results and discuss ways to distinguish between various mechanisms that may cause a yield point and apparent elastic-plastic behavior.","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143707778","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}

引用次数: 0

Coarse-grained molecular dynamics simulations of slide-ring gels under finite deformation: influence of sliding ring rearrangement on softness and extensibility.

IF 2.9 3区化学

Soft Matter Pub Date : 2025-03-26 DOI: 10.1039/d5sm00003c

Yusuke Yasuda, Takeyoshi Masumoto, Koichi Mayumi, Masatoshi Toda, Hideaki Yokoyama, Hiroshi Morita, Kohzo Ito

{"title":"Coarse-grained molecular dynamics simulations of slide-ring gels under finite deformation: influence of sliding ring rearrangement on softness and extensibility.","authors":"Yusuke Yasuda, Takeyoshi Masumoto, Koichi Mayumi, Masatoshi Toda, Hideaki Yokoyama, Hiroshi Morita, Kohzo Ito","doi":"10.1039/d5sm00003c","DOIUrl":"https://doi.org/10.1039/d5sm00003c","url":null,"abstract":"Slide-ring (SR) gels are a class of polymer gels known for their unique softness, toughness, and high extensibility. The defining structural feature of SR gels is their figure-of-eight-shaped slidable cross-links, whose sliding dynamics are believed to underpin their mechanical properties. However, the relationship between the sliding mechanics and observed mechanical behavior of SR gels remains unclear because their structure differs considerably from those of conventional fixed cross-link gels and vulcanized rubbers. In this work, we employed coarse-grained molecular dynamics simulations to investigate the mechanical behavior of SR gels up to large deformation. By visualizing the correlated distribution of network strand orientation and stress loading, we found that SR gels under strain exhibit uniform chain orientation and efficient stress dispersion throughout the network, in contrast to gels with fixed cross-links, which display regions of highly oriented and heavily stressed chains. Furthermore, we observed that the distribution of network-strand length changes under deformation, indicating that chains are reconfigured into shorter and longer sections during stretching. Notably, we demonstrated that the finite network-strand length (Nmax) determines the finite extensibility of SR gels, corresponding to the maximum elongation ratio (λmax). These findings provide new insights into the molecular mechanisms driving the high extensibility and toughness of SR gels and offer valuable guidance for designing SR gels with tailored mechanical properties.","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143707767","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}

引用次数: 0

Hybridization of colloidal handlebodies with singular defects and topological solitons in chiral liquid crystals.

IF 2.9 3区化学

Soft Matter Pub Date : 2025-03-26 DOI: 10.1039/d5sm00014a

Jun-Yong Lee, Asha Kumari, Ye Yuan, Mykola Tasinkevych, Ivan I Smalyukh

{"title":"Hybridization of colloidal handlebodies with singular defects and topological solitons in chiral liquid crystals.","authors":"Jun-Yong Lee, Asha Kumari, Ye Yuan, Mykola Tasinkevych, Ivan I Smalyukh","doi":"10.1039/d5sm00014a","DOIUrl":"https://doi.org/10.1039/d5sm00014a","url":null,"abstract":"Topology can manifest itself in colloids when quantified by invariants like Euler characteristics of nonzero-genus colloidal surfaces, albeit spherical colloidal particles are most often studied, and colloidal particles with complex topology are rarely considered. On the other hand, singular defects and topological solitons often define the physical behavior of the molecular alignment director fields in liquid crystals. Interestingly, nematic liquid crystalline dispersions of colloidal particles allow for probing the interplay between topologies of surfaces and fields, but only a limited number of such cases have been explored so far. Here, we study the hybridization of topological solitons, singular defects, and topologically nontrivial colloidal particles with the genus of surfaces different from zero in a chiral nematic liquid crystal phase. Hybridization occurs when distortions separately induced by colloidal particles and LC solitons overlap, leading to energy minimization-driven redistribution of director field deformations and defects. As a result, hybrid director configurations emerge, combining topological features from both components. We uncover a host of director field configurations complying with topological theorems, which can be controlled by applying electric fields. Rotational and translational dynamics arise due to the nonreciprocal evolution of the director fields in response to alternating electric fields of different frequencies. These findings help define a platform for controlling topologically hyper-complex colloidal structures and dynamics with electrically reconfigurable singular defects and topological solitons induced by colloidal handlebodies.","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143707772","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}

引用次数: 0

Correction: Wet spinning of sodium carboxymethyl cellulose-sodium caseinate hydrogel fibres: relationship between rheology and spinnability.

IF 2.9 3区化学

Soft Matter Pub Date : 2025-03-26 DOI: 10.1039/d5sm90047f

Lathika Vaniyan, Pallab Kumar Borah, Galina E Pavlovskaya, Nick Terrill, Joshua E S J Reid, Michael Boehm, Philippe Prochasson, Reed A Nicholson, Stefan Baier, Gleb E Yakubov

引用次数: 0

Transient stress and fabric model for quasi-static granular flows in three dimensions.

IF 2.9 3区化学

Soft Matter Pub Date : 2025-03-26 DOI: 10.1039/d4sm01535e

Eduardo Rojas, Ken Kamrin

{"title":"Transient stress and fabric model for quasi-static granular flows in three dimensions.","authors":"Eduardo Rojas, Ken Kamrin","doi":"10.1039/d4sm01535e","DOIUrl":"https://doi.org/10.1039/d4sm01535e","url":null,"abstract":"We present and validate a general three-dimensional continuum model for predicting the coupled fabric and stress transient response in 3D dense granular flows for the quasi-static regime. The model is inspired by isotropic and kinematic hardening theory, which is widely applied to plastic loading cycles in metals, which constitutes a connection between two different flowing materials through the same plastic modeling framework. The first part of the model consists of a differential evolution equation for the fabric tensor, which incorporates a new parameter called contact persistence to model the capacity of the fabric network to keep its contacts according to the relative direction of the shear-rate. The second part of the model is an expression for the shear stress comprised of a backstress, proportional to the fabric tensor, and a term proportional to the shear-rate direction. This shear stress decomposition was obtained from DEM data extracted within a 3D Couette cell during unsteady processes wherein the shear-rate direction rotates instantaneously with respect to the axis perpendicular to the walls of the cell. The results of the model are compared with DEM simulations for different changes in shear orientation, achieving a good agreement for the evolution of the fabric and deviatoric stress tensors. The model is shown to be compatible with the second law of thermodynamics, revealing that the origin of the backstress flow resistance in granular media is distinct from the cause of backstresses in metals; rather than arising from stored defect energy, it arises from the dependence of dilatancy on the alignment of the fabric and flow-rate.","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143707781","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}

引用次数: 0

Enhancing spray retention using cloaked droplets to reduce pesticide pollution.

IF 2.9 3区化学

Soft Matter Pub Date : 2025-03-25 DOI: 10.1039/d4sm01496k

Vishnu Jayaprakash, Simon Rufer, Sreedath Panat, Kripa K Varanasi

{"title":"Enhancing spray retention using cloaked droplets to reduce pesticide pollution.","authors":"Vishnu Jayaprakash, Simon Rufer, Sreedath Panat, Kripa K Varanasi","doi":"10.1039/d4sm01496k","DOIUrl":"https://doi.org/10.1039/d4sm01496k","url":null,"abstract":"Enhancing agrochemical spray retention on plant surfaces would have tremendous benefits to global health and the environment. The bouncing of sprayed pesticide droplets from hydrophobic leaves is a major source of water and soil pollution, and the resultant overuse of pesticides is a human health hazard and a financial burden for farmers. Here we report on the development of sustainable agricultural sprays consisting of cloaked droplets that significantly enhance droplet retention on plant surfaces. By leveraging wetting dynamics, we create cloaked droplets that consist of an ultra-thin food and environmentally safe oil layer (<1% by volume) that encapsulates water droplets. We develop a fundamental understanding of the dynamics of cloaked droplet impact and retention on superhydrophobic surfaces. Using high-speed imaging, we capture how the oil cloak transforms into a wetting ridge that pins the droplets and suppresses their rebound. We span a wide range of impact conditions, oils, oil viscosities, and oil volume fractions to demonstrate the robustness of the approach. By considering a balance of kinetic energy, the work of adhesion, and viscous dissipation in this four-phase system, we develop a physical model that allows us to establish a regime map for rebound suppression. Finally, these findings are implemented into a prototype sprayer which leads to a ∼5-fold reduction in spray waste on crop leaves. We believe that our spray approach can greatly reduce agrochemical pollution as well as pesticide and surfactant usage.","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143699082","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}

引用次数: 0

Sampling the large-dimensional energy landscape of a 2D granular system with the hydra string method.

IF 2.9 3区化学

Soft Matter Pub Date : 2025-03-25 DOI: 10.1039/d4sm01337a

Katherine A Newhall

{"title":"Sampling the large-dimensional energy landscape of a 2D granular system with the hydra string method.","authors":"Katherine A Newhall","doi":"10.1039/d4sm01337a","DOIUrl":"https://doi.org/10.1039/d4sm01337a","url":null,"abstract":"In this work, I improve upon the existing hydra string method [C. Moakler and K. A. Newhall, Granular Matter, 2021, 24, 24] to systematically sample the energy landscape of a low friction 2D granular system. This method climbs in random directions out of a minimum energy state, finding unique saddle transition points and the neighboring minimum energy states only to repeat the process from the newly found minima. The data is saved as a network with nodes representing the energy-minimizing states and edges representing transition pathways that are parallel to the gradient of the energy at each point along the path. I show how the hydra string method is able to produce a better sample of transition pathways between stable states compared to just randomly sampling the system. The method is also modified to take into account energy minima that are not points caused by non-mechanically stable individual particles and skip past entire configurations that are not mechanically stable. The samples reveal that the energy of the states correlates with the size of the energy barriers between them. Neighboring state energies are also correlated, with correlations decreasing with distance as measured by path length on the network.","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143699083","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}

引用次数: 0