Soft Matter最新文献

{"title":"Instabilities, thermal fluctuations, defects and dislocations in the crystal-R_I-R_II rotator phase transitions of <i>n</i>-alkanes.","authors":"Soumya Kanti Ganguly, Prabir K Mukherjee","doi":"10.1039/d4sm01170h","DOIUrl":"https://doi.org/10.1039/d4sm01170h","url":null,"abstract":"<p><p>The theoretical study of instabilities, thermal fluctuations, and topological defects in the crystal-rotator-I-rotator-II (X-R_I-R_II) phase transitions of <i>n</i>-alkanes has been conducted. First, we examine the nature of the R_I-R_II phase transition in nanoconfined alkanes. We propose that under confined conditions, the presence of quenched random orientational disorder makes the R_I phase unstable. This disorder-mediated transition falls within the Imry-Ma universality class. Next, we discuss the role of thermal fluctuations in certain rotator phases, as well as the influence of dislocations on the X-R_I phase transition. Our findings indicate that the herringbone order in the X-phase and the hexatic order in the R_II-phase exhibit quasi-long-range characteristics. Furthermore, we find that in two dimensions, the unbinding of dislocations does not result in a disordered liquid state.</p>","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143027622","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":"A multi-body finite element model for hydrogel packings: linear response to shear.","authors":"Ahmed Elgailani, Craig E Maloney","doi":"10.1039/d4sm00916a","DOIUrl":"https://doi.org/10.1039/d4sm00916a","url":null,"abstract":"<p><p>We study a multi-body finite element model of a packing of hydrogel particles using the Flory-Rehner constitutive law to model the deformation of the swollen polymer network. We show that while the dependence of the pressure, <i>Π</i>, on the effective volume fraction, <i>ϕ</i>, is virtually identical to a monolithic Flory material, the shear modulus, <i>μ</i>, behaves in a non-trivial way. <i>μ</i> increases monotonically with <i>Π</i> from zero and remains below about 80% of the monolithic Flory value at the largest <i>Π</i> we study here. The local shear strain in the particles has a large spatial variation. Local strains near the centers of the particles are all roughly equal to the applied shear strain, but the local strains near the contact facets are much smaller and depend on the orientation of the facet. We show that the slip between particles at the facets depends strongly on the orientation of the facet and is, on average, proportional to the component of the applied shear strain resolved onto the facet orientation. This slip screens the stress transmission and results in a reduction of the shear modulus relative to what one would obtain if the particles were welded together at the facet. Surprisingly, given the reduction in the shear modulus arising from the facet slip, and the spatial variations in the local shear strain inside the particles themselves, the deformation of the particle centroids is rather homogeneous with the strains of the Delaunay triangles having fluctuations of only order ±5%. These results should open the way to construction of quantitative estimates of the shear modulus in highly compressed packings <i>via</i> mean-field, effective-medium type approaches.</p>","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143031478","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":"Characterizing dynamic heterogeneities during nanogel degradation.","authors":"Zafrin Ferdous Mira, Vaibhav Palkar, Olga Kuksenok","doi":"10.1039/d4sm01256a","DOIUrl":"https://doi.org/10.1039/d4sm01256a","url":null,"abstract":"<p><p>Understanding photodegradation of nanogels is critical for dynamic control of their properties and functionalities. We focus on nanogels formed by end-linking of four-arm polyethylene glycol precursors with photolabile groups and characterize dynamic heterogeneities in these systems during degradation. We use our recently developed dissipative particle dynamics framework that captures the controlled scission of bonds between the precursors and diffusion of degraded fragments at the mesoscale. To quantify spatiotemporal fluctuations in the local dynamic behavior, we calculate the self-part of the van-Hove correlation function for the reactive beads for nanogels degrading in various environments. We demonstrate strong deviations from the Gaussian behavior during the degradation and quantify variations in the non-Gaussian parameter as a function of the relative extent of degradation. We show that for the nanogels degrading in a good solvent, the peak values in the non-Gaussian parameter are observed significantly earlier than the reverse gel point, and earlier than the peak values in the dispersity of the broken off fragments. Further, our study shows that a systematic decrease in solvent quality significantly affects the behavior of the non-Gaussian parameter as a function of the relative extent of degradation. The findings of this study allow one to quantify the dynamic heterogeneities during degradation in various environments and can potentially provide guidelines for designing controllably degrading nanocarriers.</p>","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143031479","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":"Topological defects induced by air inclusions in ferroelectric nematic liquid crystals with ionic doping.","authors":"Zhongjie Ma, Shengzhu Yi, Miao Jiang, Mingjun Huang, Satoshi Aya, Rui Zhang, Qi-Huo Wei","doi":"10.1039/d4sm01261e","DOIUrl":"https://doi.org/10.1039/d4sm01261e","url":null,"abstract":"<p><p>We report an experimental study on how topological defects induced by cylindrical air inclusions in the ferroelectric nematic liquid crystal RM734 are influenced by ionic doping, including an ionic surfactant and ionic polymer. Our results show that subtle differences in molecular structure can lead to distinct surface alignments and topological defects. The ionic surfactant induces a planar alignment, with two -1/2 line defects adhering to the cylindrical bubble surface. In contrast, the ionic polymer promotes homeotropic alignment, resulting in a -1 polar disclination around the cylindrical bubble. By numerical simulations, we verify that these topological defects are vertical lines with two dimensional polarization fields. These configurations differ from the boojums and hedgehog defects induced by air inclusions in nematic liquid crystals, highlighting the significant role of broken inversion symmetry.</p>","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143021335","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":"Entropy stabilized form chirality in curved rod nematics: structure and symmetries.","authors":"Alexandros G Vanakaras, Edward T Samulski, Demetri J Photinos","doi":"10.1039/d4sm01229a","DOIUrl":"https://doi.org/10.1039/d4sm01229a","url":null,"abstract":"<p><p>Monte Carlo molecular simulations of curve-shaped rods show the propensity of such shapes to polymorphism revealing both smectic and polar nematic phases. The nematic exhibits a nanoscale modulated local structure characterized by a unique, polar, <i>C</i>₂-symmetry axis that tightly spirals generating a mirror-symmetry-breaking organization of the achiral rods-form chirality. A comprehensive characterization of the polarity and its symmetries in the nematic phase confirms that the nanoscale modulation is distinct from the elastic deformations of a uniaxial nematic director in the twist-bend nematic phase. Instead it is shown that, analogous to the isotropic-to-nematic transition, entropy stabilizes the roto-translating polar director in the polar-twisted nematic phase. The conflation of macroscale form chirality in ferroelectric nematics with that in the twist-bend nematic stems from the misattribution of the nanoscale modulation in the lower temperature nematic \"N_X phase\" found in CB7CB dimers.</p>","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143021331","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":"Flow environment affects nutrient transport in soft plant roots.","authors":"Sumit Kumar Mehta, Anirudha Talukdar, Suraj Panja, Jinmay Kalita, Somchai Wongwises, Pranab Kumar Mondal","doi":"10.1039/d4sm01083c","DOIUrl":"https://doi.org/10.1039/d4sm01083c","url":null,"abstract":"<p><p>This work estimates Michaelis-Menten kinetics parameters for nutrient transport under varying flow rates in the soft roots of Indian mustard (<i>Brassica juncea</i>) using a plant fluidic device. To find the metallic components within the roots, inductively coupled plasma mass spectrometry (ICP-MS) analysis was performed. The flow rate-dependent metabolic changes were examined using Raman spectral analysis. In addition, three-dimensional numerical simulations were conducted to assess mechanical stresses resulting from the concentration difference that enhances osmotic pressure and flow loading at the root-liquid interface. Convection, the primary mode of nutrient transport in flowing media, was observed to reduce nutrient uptake at higher flow rates. In contrast, diffusion became more prevalent in areas where the complex root structure restricted the flow field. The concentration gradient between the upstream and downstream regions of the root caused nutrient diffusion from downstream to upstream. As seen, an increase in flow rate resulted in a decrease in root length due to the reduction of advantageous metabolites, which led to lower average mechanical stress and osmotic pressure loading. Additionally, osmotic pressure at the root-liquid interface was found to increase over time. Numerical simulations revealed that the average internal mechanical stress was substantially greater when osmotic pressure was considered. This emphasizes the importance of accounting for osmotic pressure when assessing mechanical stress in roots. This study uses a fluidic device that replicates hydroponic conditions for the first time in order to evaluate the convection-dependent Michaelis-Menten kinetics of nutrient uptake in plant roots.</p>","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142996373","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":"Collective motion and its connection to the energy landscape in 2D soft crystals.","authors":"Md Rakib Hassan, Sam R Aronow, Jack F Douglas, Francis W Starr","doi":"10.1039/d4sm01405g","DOIUrl":"https://doi.org/10.1039/d4sm01405g","url":null,"abstract":"<p><p>We examine the collective motion in computational models of a two-dimensional dusty plasma crystal and a charged colloidal suspension as they approach their respective melting transitions. To unambiguously identify rearrangement events in the crystal, we map the trajectory of configurations from an equilibrium molecular dynamics simulation to the corresponding sequence of configurations of local potential energy minima (\"inherent structures\"). This inherent structure (IS) trajectory eliminates the ambiguity that arises from localized vibrational motion. We find that the evolution of the IS trajectory in the crystal can be split into comparatively longer-lived ground states and shorter-lived discrete excited states. These discrete excited energy levels are a consequence of discrete numbers of defect clusters in the crystal. We find that the collective rearrangement occurs through different mechanisms: (i) small closed-loop motion in the ground states without the facilitation of defects, and (ii) much larger and complex open-ended particle motions in excited states that are facilitated by clusters of defects. In both cases, clusters of displacing particles can be separated into much smaller groups of replacing particles with a loop-like structure. In contrast to glass-forming liquids, the mass of the rearranging groups grows on heating towards the melting temperature rather than cooling. We find that crystal melting in these systems can be anticipated by the merging of the average time the crystal spends in the ground state with the average time in the excited states.</p>","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142996586","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":"Non-ionic surfactant self-assembly in calcium nitrate tetrahydrate and related salts.","authors":"Yashfeen Zahid, Yizhen Li, Ömer Dag, Gregory G Warr, Cemal Albayrak","doi":"10.1039/d4sm01268b","DOIUrl":"https://doi.org/10.1039/d4sm01268b","url":null,"abstract":"<p><p>Self-assembly of amphiphilic molecules can take place in extremely concentrated salt solutions, such as inorganic molten salt hydrates or hydrous melts. The intermolecular interactions governing the organization of amphiphilic molecules under such extreme conditions are not yet fully understood. In this study, we investigated the specific effects of ions on the self-assembly of the non-ionic surfactant C₁₂H₂₅(OCH₂CH₂)₁₀OH (C₁₂E₁₀) under extreme salt concentrations, using calcium nitrate tetrahydrate as a reference. The mixtures of Ca(NO₃)₂·4H₂O and C₁₂E₁₀ displayed lyotropic (H₁ and I₁) and micellar phases, in contrast to CaCl₂·<i>x</i>H₂O-C₁₂E₁₀ or CaBr₂·<i>x</i>H₂O-C₁₂E₁₀ mixtures where mesostructurally ordered salt-surfactant complexes were observed. The Ca(NO₃)₂·4H₂O-C₁₂E₁₀ system was thoroughly investigated by constructing its binary phase diagram and performing thermal and spectral comparisons with other salt hydrates. The Ca(NO₃)₂ system displayed significantly higher isotropization temperatures than zinc, aluminium, and lithium nitrate systems. ATR-FTIR analysis revealed that Ca²⁺ primarily interacts with the surfactant head groups through ion-dipole interactions, while these interactions were less pronounced with other cations. The results show that an intermediate hydration/coordination energy of the metal ion can lead to stronger metal-surfactant interactions and thermally more stable liquid crystals. Comparison between the Ca(NO₃)₂, CaCl₂, and CaBr₂ systems suggests that reduced ion pair formation enhances the interactions between Ca²⁺ and oxyethylene groups, leading to the salting-out of salt-surfactant complexes. Despite its low water content and strong intermolecular interactions, the Ca(NO₃)₂·<i>x</i>H₂O-C₁₂E₁₀ system exhibited an electrical conductivity of up to 1.0 × 10^-3 S cm^-1 with 4 water molecules per salt, making it a promising medium for electrochemical applications.</p>","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142996545","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":"The effect of selective surface interaction on polymer phase separation with explicit polydispersity during polymerization.","authors":"Hyeonmin Jeong, Junsi Gu, Paul Mwasame, Kshitish Patankar, Decai Yu, Charles E Sing","doi":"10.1039/d4sm01077a","DOIUrl":"https://doi.org/10.1039/d4sm01077a","url":null,"abstract":"<p><p>In polymerization-induced phase separation, the impact of polymer-substrate interaction on the dynamics of phase separation for polymer blends is important in determining the final morphology and properties of polymer materials as the surface can act as another driving force for phase separation other than polymerization. We modify the previously-developed polymerizing Cahn-Hilliard (pCH) method by adding a surface potential to model the phase separation behavior of a mixture of two species independently undergoing linear step-growth polymerization in the presence of a surface. In our approach, we explicitly model polydispersity by separately considering different molecular-weight components with their own respective diffusion constants, and with the surface potential preferentially acting on only one species. We first show that the surface potential induces faster phase separation of smaller molecules at early stages before the degree of polymerization becomes large enough to drive bulk phase separation. This model is then used to investigate the degree of anisotropic ordering in a direction perpendicular to the surface over various polymerization rates <i>k̃</i> and strengths of the potential <i>Ṽ</i>. We find that at low <i>k̃</i>, smaller molecules have sufficient time to diffuse and accumulate at the potential surface, resulting in richer production of heavier polymers at the surface without the need for larger polymers to diffuse on their own toward the surface. Conversely, at high <i>k̃</i>, larger polymers first evenly accumulate throughout the system before undergoing phase separation; the concentration wave initiated from the potential surface then propagates into the bulk, resulting in anisotropic phase separation.</p>","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142996491","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":"Functionalized amino acid-based injectable hydrogels for sustained drug delivery.","authors":"Arpita Roy, Kalipada Manna, Shaon Dey, Kanta Chakraborty, Santanu Dhara, Sagar Pal","doi":"10.1039/d4sm01402b","DOIUrl":"https://doi.org/10.1039/d4sm01402b","url":null,"abstract":"<p><p>Drug delivery vehicles optimize therapeutic outcomes by enhancing drug efficacy, minimizing side effects, and providing controlled release. Injectable hydrogels supersede conventional ones in the field of drug delivery owing to their less invasive administration and improved targeting. However, they face challenges such as low biodegradability and biocompatibility, potentially compromising their effectiveness. To address these limitations, a modified amino acid-based pH-responsive injectable shear-thinning hydrogel <i>cl</i>-β-CD-<i>g</i>-p(Gly-MA) has been developed as an efficient drug carrier. In the two-step synthetic approaches, first, the well-known amino acid glycine (Gly) is modified to form glycine methacrylate (Gly-MA). Afterward, Gly-MA is chemically crosslinked with β-cyclodextrin (β-CD), an oligosaccharide, using an ethylene glycol dimethacrylate (EGDMA) crosslinker. The presence of these biomaterials as building blocks enhances the biocompatibility, hemocompatibility, and biodegradability of the hydrogel. They also reduce the risk of immunogenicity. The unique property of easy injectability enables minimally invasive administration. This feature also helps prolong drug retention at the target site, further optimizing drug delivery efficiency. Moreover, the pH-responsive feature of the developed <i>cl</i>-β-CD-<i>g</i>-p(Gly-MA) hydrogel ensures controlled drug release in response to the physiological conditions of the target site, enhancing therapeutic efficacy. The study focuses on investigating the <i>in vitro</i> loading and release of diclofenac sodium (DS), a non-steroidal anti-inflammatory drug (NSAID) commonly used to treat arthritic pain and inflammation.</p>","PeriodicalId":103,"journal":{"name":"Soft Matter","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142996536","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}