Rheologica Acta最新文献

{"title":"Rheology of fiber–reinforced xanthan gum solutions","authors":"Mohsen Faramarzi,&nbsp;Seyed Mohammad Taghavi","doi":"10.1007/s00397-025-01544-5","DOIUrl":"10.1007/s00397-025-01544-5","url":null,"abstract":"<div><p>We investigate the rheology of synthetic organic fiber–reinforced xanthan gum solutions, via varying fiber concentration (0–4 g/L), length (1.8–12 mm), and temperature (10–50<span>(^circ)</span>C). Steady shear sweeps, oscillatory amplitude sweeps, and creep tests are performed. Three regimes are identified: (i) weak-interaction, where short fibers or low concentrations have little effect; (ii) shear-responsive networks, where intermediate fibers form weak structures at low shear that collapse under higher shear; and (iii) network-dominated, where higher concentrations and longer fibers increase viscosity across all shear rates and intensify non-Newtonian behavior. Oscillatory and creep tests confirm progressive network formation, increased elasticity, higher storage modulus, and elevated crossover stresses. Creep data show a transition from fluid-like to bounded, solid-like deformation. Temperature induces thinning, partly offset at higher loadings, while longer fibers raise yield stress and consistency, especially at high concentrations.</p></div>","PeriodicalId":755,"journal":{"name":"Rheologica Acta","volume":"65 3","pages":"241 - 254"},"PeriodicalIF":3.0,"publicationDate":"2026-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147560488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Slip flows of a Bingham fluid in curved channels","authors":"Simon Cox,&nbsp;Seyed Mohammad Taghavi","doi":"10.1007/s00397-026-01548-9","DOIUrl":"10.1007/s00397-026-01548-9","url":null,"abstract":"<div><p>Motivated by the treatment of varicose veins with aqueous foams, we determine the velocity profiles and yield surface positions for pressure-driven flows of a Bingham fluid in curved channels, incorporating Navier wall slip to capture the slip behavior of aqueous foams. Assuming a constant pressure gradient – consistent with syringe-driven injection in sclerotherapy – we reproduce a closed-form analytic solution for the flow in a straight channel, and extend this to a uniformly curved channel consisting of a section of an annulus. We find that increasing the slip length in the curved channel moves the unyielded fluid, or plug, towards the inside of the channel and slightly decreases the plug width. Channels with a change in curvature are tackled numerically, with a procedure that is validated against the analytic results. We solve for the flow of a Bingham fluid in the transition region between a straight and a uniformly curved channel and in a non-uniform sinusoidal channel where the wall curvature changes continuously. We find that there is greater yielding of the fluid in curved channels, caused by an increase in the shear stresses. As the slip length increases, there is a reduction in the area of unyielded fluid in regions of high wall curvature. In the context of varicose vein sclerotherapy, our results suggest that slip has both positive and negative consequences: it eliminates the possibility of static regions of foam developing in areas of high curvature in the vein, but also reduces the plug width in general, affecting the efficacy with which the foam displaces blood from the vein.</p></div>","PeriodicalId":755,"journal":{"name":"Rheologica Acta","volume":"65 4","pages":"353 - 367"},"PeriodicalIF":3.0,"publicationDate":"2026-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00397-026-01548-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147588391","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multilayer nanofilled polymer systems under extensional flow: Role of filler aspect ratio and interfacial chain dynamics","authors":"Jixiang Li,&nbsp;Emna Masghouni,&nbsp;Guillaume Sudre,&nbsp;Abderrahim Maazouz,&nbsp;Khalid Lamnawar","doi":"10.1007/s00397-026-01547-w","DOIUrl":"10.1007/s00397-026-01547-w","url":null,"abstract":"<div><p>The influence of carbon nanofillers on the melt extensional behavior of multilayer polymer nanocomposites was investigated using linear low-density polyethylene (LLDPE) as matrices embedded with either carbon nanostructures (CNS) or multi-walled carbon nanotubes (MWCNTs). Multilayer films with controlled layer architectures were fabricated via forced-assembly co-extrusion. Extensional rheology tests revealed that CNS, due to their higher aspect ratio and stronger interfacial interactions with LLDPE chains, significantly enhanced the extensional viscosity and strain hardening behavior, especially in highly layered (1025L) systems. By contrast, MWCNT-filled films exhibited extensional responses similar to the neat LLDPE matrix, indicating minimal nanofiller–polymer interaction. Microstructural analyses via SEM, TEM, and SAXS confirmed the alignment of CNS under extension and the presence of thick interfacial bound polymer layers, leading to complex interfacial chain relaxation dynamics. Furthermore, stress yielding observed in CNS-filled systems with fewer layers (e.g., 9L) was attributed to structural instabilities and filler-rich layer breakup. These findings provide new insights into the role of nanofiller morphology and interfacial dynamics in tuning extensional rheology, with implications for advanced polymer processing and modeling of nanocomposite systems.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":755,"journal":{"name":"Rheologica Acta","volume":"65 2","pages":"167 - 183"},"PeriodicalIF":3.0,"publicationDate":"2026-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147579525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Melt strain hardening of polypropylenes and its relation to molecular structure: a review","authors":"Helmut Münstedt","doi":"10.1007/s00397-025-01543-6","DOIUrl":"10.1007/s00397-025-01543-6","url":null,"abstract":"<div><p>Strain hardening of polymer melts is a rheological feature that improves properties of items processed by operations with pronounced extensional deformations. Thus, developments have been undertaken over the years to modify linear polypropylenes not showing strain hardening. The different ways to generate strain hardening polypropylenes are reviewed, and it is shown how rheological relations can be used for their characterization. Chemical reactions are shortly addressed, but the main focus lies on the generation of long-chain branches by electron-beams or γ-irradiation. Blends of a commercial long-chain branched and a linear isotactic polypropylene exhibit strain hardening and branching features determined in the highly diluted state by usual techniques that are comparable to the electron-beam irradiated samples. But measurements of the zero-shear viscosity as a function of molar mass provide a hint to different branching structures: Tree-like components for the blends and star-like molecules for the weakly electron-beam irradiated species. Using the results of these rheological methods, the influence of various experimental parameters like type of irradiation source and irradiation dose or temperature and molar mass of the irradiated polypropylene on the branching structures is elucidated. Furthermore, the different dependencies of strain hardening on elongation rate for samples with various branching structures are discussed, and a qualitative interpretation is presented.</p><h3>Graphical abstract</h3><div><figure><div><div><picture><img></picture></div></div></figure></div></div>","PeriodicalId":755,"journal":{"name":"Rheologica Acta","volume":"65 2","pages":"93 - 111"},"PeriodicalIF":3.0,"publicationDate":"2026-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00397-025-01543-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147579405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The modified Rouse model incorporating supplementary effects: I. Nonlinear modification for chain volume conservation and anisotropic friction","authors":"Youngdon Kwon","doi":"10.1007/s00397-026-01545-y","DOIUrl":"10.1007/s00397-026-01545-y","url":null,"abstract":"<div>\u0000 \u0000 <p>This study reexamines the constraint for volume conservation of the Rouse chain proposed recently (Kwon 2024). We provide conceivable reasoning for the constraint written in terms of the normal mode amplitude. Formulating the necessary number of constraints is verified to require vanishing correlation between distinct linear combinations of segmental vectors. Considering these observations, we prove that the normal mode amplitude is the only choice appropriate for the constraint. The constitutive equation derived expresses shear thinning with the exponent in the range between <span>(:-0.4)</span> and <span>(:-0.6)</span>, and therefore approximately matches the experiments. Second, we investigate the anisotropic friction. The anisotropy is modeled by substituting the friction tensor. We decompose the inverse of the friction tensor into reduced, isotropic and accreted friction terms. This implementation enables modeling finite value of <i>N</i>₂ as well as friction reduction. Probable correlation between <i>N</i>₂ and the extensional friction reduction has been also demonstrated.</p>\u0000 </div>","PeriodicalId":755,"journal":{"name":"Rheologica Acta","volume":"65 2","pages":"153 - 166"},"PeriodicalIF":3.0,"publicationDate":"2026-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00397-026-01545-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147579235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Solvent evaporation induces stiffening in caber and electrospinning of volatile polymer solutions","authors":"Étienne J. Beaudoin,&nbsp;Ricardo J. Zednik,&nbsp;Nicole R. Demarquette","doi":"10.1007/s00397-026-01550-1","DOIUrl":"10.1007/s00397-026-01550-1","url":null,"abstract":"<div>\u0000 \u0000 <p>Nanoscale polymer fibers have gained increasing attention over the past two decades due to their applications in filtration, sensing, and biomedical devices. These fibers are commonly produced by electrospinning, where a polymer solution is stretched in extension and rapidly solidifies through solvent evaporation. Since flow behavior plays a key role in determining fiber morphology, extensional rheology techniques such as Capillary Breakup Extensional Rheometry (CaBER) are often used to characterize polymer solutions. Like electrospinning, CaBER involves the formation and thinning of a filament exposed to ambient air. In this study, the influence of solvent evaporation on both electrospinning and CaBER measurements is investigated under controlled ambient vapor pressures (25% to 90%) using aqueous pullulan solutions. Electrospinning results show that lower vapor pressure accelerates solvent evaporation, leading to early jet solidification and the formation of thicker fibers. In parallel, CaBER measurements reveal longer relaxation times at low vapor pressure, suggesting evaporation-induced stiffening. To better understand this effect, a model was developed to calculate solvent evaporation at the filament surface and the resulting radial redistribution of solvent within the filament by diffusion. Using experimental filament radius data as input, the polymer concentration profile across the filament cross-section was computed over time. From these local concentration fields, the corresponding apparent bulk viscosity was calculated using a concentration-dependent viscosity relationship. Simulation results show that at low vapor pressure, polymer concentration increases near the surface due to solvent loss, which in turn leads to a significant rise in the apparent viscosity as the filament thins. The convergence of results from electrospinning, CaBER, and modeling highlights the strong influence of solvent evaporation on extensional flow behavior. These findings emphasize the need for careful environmental control and evaporation-aware modeling when characterizing volatile polymer solutions.</p>\u0000 <span>AbstractSection</span>\u0000 Graphical abstract\u0000 <div><figure><div><div><picture><source><img></source></picture></div></div></figure></div>\u0000 \u0000 </div>","PeriodicalId":755,"journal":{"name":"Rheologica Acta","volume":"65 4","pages":"303 - 315"},"PeriodicalIF":3.0,"publicationDate":"2026-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147588546","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shear jamming and nonlinear rheology of chocolate suspensions","authors":"Michel Orsi,&nbsp;Veeraj Shah,&nbsp;Mahesh Padmanabhan,&nbsp;Thomas Curwen,&nbsp;Jeffrey F. Morris","doi":"10.1007/s00397-026-01546-x","DOIUrl":"10.1007/s00397-026-01546-x","url":null,"abstract":"<div><p>We experimentally investigate the rheology of dark chocolate pastes in both industrially relevant pre-refined form and simplified model systems. Steady and oscillatory shear experiments reveal yielding, pronounced shear-thinning, and stress-dependent hysteresis governed by solid loading. Fitting the viscosity data with the Maron-Pierce model provides stress-dependent maximum flowable fractions <span>(phi _mathrm{{m}}(sigma ))</span>, defining yield loci in the <span>((phi , sigma ))</span> plane. Their variation with stress quantifies the coupled roles of friction and adhesion in setting flow limits. Large-amplitude oscillatory shear tests characterize transitions from elastic to viscous behavior and identify distinct recovery pathways near jamming. Contact-stress decomposition separates hydrodynamic and frictional contributions, confirming that adhesive contact networks dominate stress transmission in pre-refined pastes. These results establish chocolate pastes as dense, adhesive suspensions whose flow is controlled by the interplay of friction and adhesion, offering quantitative benchmarks for constitutive modeling and linking chocolate processing to the broader physics of constraint rheology.</p></div>","PeriodicalId":755,"journal":{"name":"Rheologica Acta","volume":"65 2","pages":"185 - 204"},"PeriodicalIF":3.0,"publicationDate":"2026-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147579517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of interstitial fluid viscosity on the vibrational response of particle-fluid mixtures","authors":"Amir Kafaei,&nbsp;Louis Gosselin,&nbsp;Houshang Alamdari,&nbsp;Seyed Mohammad Taghavi","doi":"10.1007/s00397-025-01542-7","DOIUrl":"10.1007/s00397-025-01542-7","url":null,"abstract":"<div>\u0000 \u0000 <p>Carbon anodes used in the Hall-Héroult process for aluminum production are manufactured by applying vertical vibration in the vibro-compaction stage to improve homogeneity and density. To investigate the effect of fluid viscosity on this stage, we prepared model mixtures of coke particles with glycerin–water fluids of varying viscosities, poured them into a transparent vessel, subjected them to vertical vibration, and tracked the bulk surface profile with an ultra-high-speed camera. Higher-viscosity mixtures formed bulks with larger angles of repose due to stronger cohesive forces. Consequently, after vibration, these mixtures compacted more slowly and less uniformly, requiring more time to stabilize. This resistance to compaction stems from a stronger cohesive network, created by viscous and capillary forces that resist particle movement and rearrangement. At the same time, this network helps viscous mixtures transmit vibration energy more effectively, causing the bulk surface to oscillate with larger amplitude.</p>\u0000 </div>","PeriodicalId":755,"journal":{"name":"Rheologica Acta","volume":"65 3","pages":"255 - 273"},"PeriodicalIF":3.0,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147561631","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integral fractional viscoelastic models in SPH: LAOS simulations versus experimental data","authors":"Luca Santelli,&nbsp;Adolfo Vázquez-Quesada,&nbsp;Aizeti Burgoa,&nbsp;Aitor Arriaga,&nbsp;Rikardo Hernandez,&nbsp;Marco Ellero","doi":"10.1007/s00397-025-01533-8","DOIUrl":"10.1007/s00397-025-01533-8","url":null,"abstract":"<div><p>The rheological behaviour of a polymer was investigated by performing numerical simulations in complex flow and comparing them to experiments. For our simulations, we employed a Smoothed Particle Hydrodynamics scheme, utilising an integral fractional model based on the K-BKZ framework. The results are compared with experiments performed on melt-state isotactic polypropylene under medium and large amplitude oscillatory shear. The numerical results are in good agreement with the experimental data, and the model is able to capture and predict both the linear and the non-linear viscoelastic behaviours of the polymer melt. Results show that equipping SPH with an integral fractional model is a promising approach for the simulation of complex polymeric materials under realistic conditions.</p><h3>Graphical abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":755,"journal":{"name":"Rheologica Acta","volume":"64 12","pages":"691 - 707"},"PeriodicalIF":3.0,"publicationDate":"2026-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026864","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sedimentation and yield stress of magnetorheological fluids; challenges and new directions","authors":"Rami Yazeed Khaleel Mousa,&nbsp;Mahmoud Z. Ibrahim,&nbsp;A. Hayyan,&nbsp;Hanee F. Hizaddin","doi":"10.1007/s00397-025-01536-5","DOIUrl":"10.1007/s00397-025-01536-5","url":null,"abstract":"<div><p>Magnetorheological fluids (MRFs) are a class of smart materials that exhibit a rapid and reversible change in rheological properties when external magnetic field is applied. Despite their potential, sedimentation of magnetic particles, and off-state viscosity, hinder their widespread and adoption in industrial applications. Additionally, increasing the yield stress would expand the application of MRF in wider sectors. Addressing these limitations has become a key focus of research in the field. Several approaches have been discussed such as the use of nanoparticle additives, coatings, and alternative MRF compositions for the stabilization and strengthening of MRFs. While these methods have demonstrated partial success, trade-offs between key parameters, such as stability and yield stress, remain an ongoing challenge. By consolidating insights from recent advancements, this review highlights the progress made and identifies new directions for future research. The goal is to provide a better understanding of the techniques and strategies that researchers have developed to refine MRF performance and expand their practical applications.</p><h3>Graphical abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":755,"journal":{"name":"Rheologica Acta","volume":"65 2","pages":"113 - 151"},"PeriodicalIF":3.0,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147579309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}