Soft MatterPub Date : 2025-07-03DOI: 10.1039/d5sm00402k
Jianli Liu, Marco G Mazza, Yunyun Li, Fabio Marchesoni, Sergey Savel'ev
{"title":"Artificial neurons made of active matter memristors.","authors":"Jianli Liu, Marco G Mazza, Yunyun Li, Fabio Marchesoni, Sergey Savel'ev","doi":"10.1039/d5sm00402k","DOIUrl":"https://doi.org/10.1039/d5sm00402k","url":null,"abstract":"<p><p>In this study we propose a new class of artificial neurons and memristors made of active chiral particles. We formulate a single-particle model to simulate active chiral particle behavior in a two-terminal device, with resistance depending on the particle position. We create a dynamical phase map connecting particle trajectories and memristor electrical properties to applied voltage and particle's self-propulsion parameters. Analysis of spiking modes in artificial neurons, with and without noise, shows the memristor switches between high- and low-resistance states, exhibiting stable limit cycles in the position-voltage phase response.</p>","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144551469","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}
Soft MatterPub Date : 2025-07-02DOI: 10.1039/d5sm00236b
Madina Almukambetova, Hamed Almohammadi, Florine Schleiffer, Raffaele Mezzenga
{"title":"Double symmetry breaking in filamentous colloidal tactoids.","authors":"Madina Almukambetova, Hamed Almohammadi, Florine Schleiffer, Raffaele Mezzenga","doi":"10.1039/d5sm00236b","DOIUrl":"https://doi.org/10.1039/d5sm00236b","url":null,"abstract":"<p><p>Understanding the dynamics of liquid crystalline tactoids under external forces is of great importance due to their potential applications in optics, medical devices, and displays. However, only recently have tactoids started to be studied systematically under external forces, particularly under extensional flow. Here, we subject tactoids to a shear flow field and study their deformation dynamics under varying conditions of shear and time scales. Using amyloids and nanocellulose to form tactoids from model filamentous colloids with opposite sequences of chirality amplification (left-handed mesoscopic → right-handed cholesteric for amyloids; right-handed mesoscopic → left-handed cholesteric for nanocellulose), we show a complex deformation mechanism in their shape and internal structure under shear flow. When tactoids deform perpendicularly to their long axis, a double symmetry breaking occurs in both their contour shape, with the emergence of a kink, and the orientation of their nematic field. We further show that the mesoscopic chirality of the building blocks directs the position of the kink, with the macroscopic tactoid asymmetry being mirrored when inverting the mesoscopic chirality of the constitutive filamentous colloids, <i>e.g.</i>, from the left-handed amyloids to the right-handed nanocellulose.</p>","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144537509","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}
Soft MatterPub Date : 2025-06-30DOI: 10.1039/D5SM00361J
Bharti Dabra and Harsh Soni
{"title":"Depletion effect in an active chiral system†","authors":"Bharti Dabra and Harsh Soni","doi":"10.1039/D5SM00361J","DOIUrl":"10.1039/D5SM00361J","url":null,"abstract":"<p >We investigate the dynamics of ring-shaped chiral particles immersed in a monolayer of hard spherical beads, confined between two vertically vibrating plates. At high bead concentrations, we observe depletion-like attraction between the rings in both co-rotating and counter-rotating configurations, leading to the formation of a dimer. Notably, the range of this interaction extends over several bead diameters, in contrast to passive systems where interactions are typically limited to the particle size. More intriguingly, at low bead concentrations, the rings exhibit mutual repulsion in both cases, which we attribute to a localized high bead concentration between them—suggesting a mechanism opposite to conventional depletion interactions. Additionally, we examine the diffusive properties of dimerized rings and compare them with those of an isolated ring. While the angular diffusion of the dimer is significantly suppressed compared to that of a single ring, its translational diffusion remains nearly unchanged.</p>","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" 29","pages":" 5894-5901"},"PeriodicalIF":2.9,"publicationDate":"2025-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2025/sm/d5sm00361j?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144525552","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}
Soft MatterPub Date : 2025-06-30DOI: 10.1039/D5SM00252D
Stephen L. Flores, Christopher P. Cabry, Hugh Barlow, Joseph Peterson, Joanne L. Cook, Olga Mihailova, Ian P. Stott, Carlos Avendaño and Christopher Hardacre
{"title":"Molecular architecture modulates self-assembly and micellar rheology of model ionic surfactant systems†","authors":"Stephen L. Flores, Christopher P. Cabry, Hugh Barlow, Joseph Peterson, Joanne L. Cook, Olga Mihailova, Ian P. Stott, Carlos Avendaño and Christopher Hardacre","doi":"10.1039/D5SM00252D","DOIUrl":"10.1039/D5SM00252D","url":null,"abstract":"<p >Understanding and predicting the rheology of micellar systems is key in formulation design with wide-reaching implications for the development of products such as shampoos and detergents. In micellar systems comprising ionic surfactants, predictive models are uniquely challenging to construct as a result of the combined effects of salt screening and surfactant polydispersity on micelle self-assembly. In this work, we provide critical insights into how the amphiphilic nature of ionic surfactants controls self-assembly and rheological behaviour. For pure sodium lauryl ether sulphate surfactants, we demonstrate that the properties of micellar solutions can be described from the average properties of the constituent ingredients. Furthermore, we show that there are three distinct viscosity regimes with varying salt concentrations, and that formulation/property relationships can be systematically controlled by three key aspects of the surfactant molecular geometry in relation to micelle self-assembly: (1) the size of the hydrophilic headgroup (degree of ethoxylation), (2) the length of the hydrocarbon tail, and (3) the polydispersity of the surfactant solutions. In systems with multiple headgroup lengths, the salt concentration required to reach peak viscosity depends exclusively on the average number of ethoxy linkers, while the peak viscosity varies with the relative proportions of the surfactant components. The observed Gaussian symmetry in viscosity trends underscores the intricate relationship between molecular structure and macroscopic behaviour in these systems. These findings have implications for improvements in rheological, thermodynamics, molecular, and predictive models and the design and development of novel formulations.</p>","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" 29","pages":" 5990-5997"},"PeriodicalIF":2.9,"publicationDate":"2025-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2025/sm/d5sm00252d?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144574518","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":"Splay and bend deformations in cells near corners†","authors":"Aniruddh Murali, Prasoon Awasthi, Kirsten Endresen, Arkadiusz Goszczak and Francesca Serra","doi":"10.1039/D5SM00093A","DOIUrl":"10.1039/D5SM00093A","url":null,"abstract":"<p >The study of spindle-like cells as nematic liquid crystals has led to remarkable insights in the understanding of tissue organization and morphogenesis. In the characterization of this anomalous liquid crystal material, we focus on the energetic cost of splay and bend deformations, in order to determine the elastic anisotropy of the material, <em>i.e.</em> the ratio of the elastic constants associated with splay and bend. We explore the behavior of monolayers of cells in proximity to corners, where cells arrange in splay or bend configuration, depending on the amplitude of the wedge angle. The angle at which splay and bend deformations are equally likely is determined by the ratio between splay and bend elastic constants. Our data suggest that for fibroblast cells the common approximation of bend and splay constants being equal is valid.</p>","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" 28","pages":" 5804-5812"},"PeriodicalIF":2.9,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144493187","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":"Precise detection of local relaxation of amorphous polymers at low temperatures via O2 diffusion probed by a dual-luminescent imide compound†","authors":"Rika Watanabe, Marina Doi, Haonan Liu, Masatoshi Tokita and Shinji Ando","doi":"10.1039/D5SM00394F","DOIUrl":"10.1039/D5SM00394F","url":null,"abstract":"<p >Local relaxation (LR) of six types of amorphous polymers was precisely monitored at low temperatures (<160 K) using the intensity ratio of phosphorescence (PH) to fluorescence of a dual-luminescent imide compound as a probe for oxygen (O<small><sub>2</sub></small>) diffusion. The PH of the imide compound dispersed in the polymer matrices was quenched by O<small><sub>2</sub></small>, and the temperature-dependent variation of the PH intensity indicates that the γ-relaxation of the polymer matrix plays a crucial role in O<small><sub>2</sub></small> diffusion. This method offers a novel analytical tool for detecting LR phenomena in amorphous polymers at low temperatures.</p>","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" 27","pages":" 5393-5397"},"PeriodicalIF":2.9,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144493185","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}
Soft MatterPub Date : 2025-06-26DOI: 10.1039/D5SM00371G
Pierre Martin, Tapan Chandra Adhyapak and Holger Stark
{"title":"E. coli bacterium tumbling in bulk and close to surfaces: a simulation study†","authors":"Pierre Martin, Tapan Chandra Adhyapak and Holger Stark","doi":"10.1039/D5SM00371G","DOIUrl":"10.1039/D5SM00371G","url":null,"abstract":"<p >Motility is fundamental to the survival and proliferation of microorganisms. The <em>E. coli</em> bacterium propels itself using a bundle of rotating helical flagella. If one flagellum reverses its rotational direction, it leaves the bundle, performs a polymorphic transformation, and the bacterium tumbles. The <em>E. coli</em> bacterium is hydrodynamically attracted to surfaces. This prolongs its residence time, while tumbling facilitates surface detachment. We develop a model of <em>E. coli</em> that uses an extended Kirchhoff-rod theory to implement flagellar flexibility as well as different polymorphic conformations and perform hydrodynamic simulations with the method of multi-particle collision dynamics (MPCD). To establish a reference case, we determine the distribution of tumble angles in the bulk fluid. It shows good agreement with experiments, when we always choose the same tumble time. Increasing the hook stiffness, narrows the tumble angle distribution and reduces the flagellar dispersion during tumbling. Close to a bounding surface, the tumble angle distribution is shifted to smaller angles, while flagellar dispersion is reduced. Reorientation within the plane favors the forward direction, which might be an explanation for prolonged run times observed in experiments.</p>","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" 29","pages":" 5921-5934"},"PeriodicalIF":2.9,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2025/sm/d5sm00371g?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144537508","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}
Soft MatterPub Date : 2025-06-26DOI: 10.1039/D5SM00201J
Hiroki Miyazako, Hiroyuki Miyoshi and Takaaki Nara
{"title":"Defect dynamics in dry active nematics by residue calculus for holomorphic functions of nematic director field","authors":"Hiroki Miyazako, Hiroyuki Miyoshi and Takaaki Nara","doi":"10.1039/D5SM00201J","DOIUrl":"10.1039/D5SM00201J","url":null,"abstract":"<p >This paper proposes a theory for modeling the dynamics of topological defects in dry active nematics. We introduce a holomorphic function for integral curves of the director field and show the density of the integral curves corresponds to that of active nematic liquid crystals such as confined spindle-shaped cells. Then, we derive equations of motion for defects by considering active stress defined from the integral curves. A mathematical analysis of the equations reveals that the dynamics of the defects can be explicitly expressed with the residues of holomorphic functions derived from the director field. We verify the proposed theory using existing work on the motion of a defect pair and demonstrate estimation of parameters for active stress by cell culture experiments.</p>","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" 29","pages":" 5947-5956"},"PeriodicalIF":2.9,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2025/sm/d5sm00201j?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144551470","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}
Soft MatterPub Date : 2025-06-25DOI: 10.1039/D5SM00126A
Spyros V. Kallivokas, Anthony Chazirakis, Rohit Ghanta, Anastassia Rissanou, Patrycja Polińska, Craig Burkhart, Manolis Doxastakis and Vagelis Harmandaris
{"title":"Elastic, viscoelastic, dynamic, topological and structural properties of crosslinked SBR through atomistic molecular dynamics simulations†","authors":"Spyros V. Kallivokas, Anthony Chazirakis, Rohit Ghanta, Anastassia Rissanou, Patrycja Polińska, Craig Burkhart, Manolis Doxastakis and Vagelis Harmandaris","doi":"10.1039/D5SM00126A","DOIUrl":"10.1039/D5SM00126A","url":null,"abstract":"<p >In this research work, we provide a detailed investigation of the structural and viscoelastic properties of crosslinked styrene butadiene rubber (SBR) networks that are studied using atomistic molecular dynamics simulations. The composition of the system ratio is (styrene/<em>trans</em>/vinyl/<em>cis</em>): (15/33/26/26) by weight and a 4-atom sulfur chain was used as a hardener for the crosslinking process. The main goal of our work is to characterize a fully percolated SBR network, with a crosslinking density of 8%, at the molecular level, structurally, mechanically and topologically and compare its properties with a system with a lower crosslinking density (3%) and the non crosslinked SBR melt. SBR crosslinked systems are generated <em>via</em> a recently proposed crosslinking algorithm. The shear stress relaxation modulus and the mean square displacement (MSD) were calculated for all systems along with structural properties, such as the pair distribution function, angles and dihedral distributions, and statistical distributions of the atoms between the crosslinks, and finally the topology of these networks was investigated according to the number of clusters that are created during the different crosslink densities, the molecular weight fraction of the largest cluster in these networks, and finally the percolation threshold. The results indicate that the higher we crosslink the SBR, the stiffer our final rubber becomes according to the results of the dynamics and rheology. We further probe the dependence of the structural and viscoelastic properties of the SBS rubber on crosslinking density by comparing a fully percolated system with one having lower crosslinking density (3%) and the non crosslinked SBR melt.</p>","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" 28","pages":" 5743-5751"},"PeriodicalIF":2.9,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144482626","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}
Soft MatterPub Date : 2025-06-25DOI: 10.1039/D5SM00373C
Eric Khoudi Omori, Renato Ferreira de Souza, Rodolfo Teixeira de Souza and Rafael Soares Zola
{"title":"Winding up dynamics for matched and unmatched elastic constants in chiral nematic liquid crystals†","authors":"Eric Khoudi Omori, Renato Ferreira de Souza, Rodolfo Teixeira de Souza and Rafael Soares Zola","doi":"10.1039/D5SM00373C","DOIUrl":"10.1039/D5SM00373C","url":null,"abstract":"<p >Recently discovered materials have opened up the possibility of easily and repeatably altering the ratio among the elastic constants characterizing nematic liquid crystals. These ratios are crucial for defining the pathways for the relaxation process from the unwound state to the Grandjean (planar) state in chiral nematics. In this study, we use the Landau–de Gennes method in the <strong>Q</strong>-tensor formalism to investigate this textural transition for different bend-to-twist ratios representing nematic phases that are currently easily prepared. We also examine the effect of varying alignment conditions and strength on this transition and make qualitative comparisons with experimental data. This work demonstrates how the dynamics are entirely different under small changes in the material and the confinement and how one can use its results to design reflective chiral nematic displays.</p>","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" 29","pages":" 5969-5979"},"PeriodicalIF":2.9,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2025/sm/d5sm00373c?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144558560","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}