Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation M. Laurati, S. U. Egelhaaf, G. Petekidis; Nonlinear rheology of colloidal gels with intermediate volume fraction. Journal Rheology 1 May 2011; 55 (3): 673–706. https://doi.org/10.1122/1.3571554 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex...

Concentrated hard-sphere suspensions and glasses are investigated with rheometry, confocal microscopy, Brownian dynamics simulations during start-up shear, providing a link between microstructure, dynamics, rheology. The microstructural anisotropy is manifested in the extension axis where maximum of pair-distribution function exhibits minimum at stress overshoot. interplay relaxation shear advection as well available free volume determine structural magnitude Shear-induced cage deformation...

We investigate the structural, dynamical, and viscoelastic properties of colloid-polymer mixtures at intermediate colloid volume fraction varying polymer concentrations, thereby tuning attractive interactions. Within examined range samples varied from fluids to gels. In liquid phase, an increasing correlation length density fluctuations when approaching gelation boundary was observed by static light scattering microscopy, indicating clustering formation space-spanning networks....

Abstract Many natural and industrial processes rely on constrained transport, such as proteins moving through cells, particles confined in nanocomposite materials or gels, individuals highly dense collectives vehicular traffic conditions. These are examples of motion crowded environments, which the host matrix may retain some glass-like dynamics. Here we investigate transport a colloidal model system, dilute small spheres move slowly rearranging, glassy large spheres. Using confocal...

The history dependence of glasses formed from flow-melted steady states by a sudden cessation the shear rate γ[over ˙] is studied in colloidal suspensions, molecular dynamics simulations and mode-coupling theory. In an ideal glass, stresses relax only partially, leaving behind finite persistent residual stress. For intermediate times, relaxation curves scale as function ˙]t, even though no flow present. macroscopic stress evolution connected to length liquefaction displayed microscopic...

Microplastic (MP) pollution is a growing concern in every known ecosystem. However, MP presence groundwaters and the ecological impact they can have on groundwater fauna still poorly investigated. Here, we assess of MPs three Italian bodies, comprising two karst caves monitoring bores saturated alluvial aquifer. In addition to water samples, invertebrates were collected their potential ingestion MPs. For chemical characterization polymers was done by Fourier Transform Infrared Spectroscopy...

We investigate stresses and particle motion during the start-up of flow in a colloidal dispersion close to arrest into glassy state. A combination molecular dynamics simulation, mode-coupling theory confocal microscopy experiments is used origins widely observed stress overshoot (previously not reported) super-diffusive transient dynamics. link between macro-rheological versus strain curves microscopic established. Negative correlations auto-correlation function potential are found...

We investigate the dynamics of water absorbed in amorphous and semicrystalline aromatic polyamide copolymers. The combination dielectric spectroscopy quasi-elastic neutron scattering experiments allows us to characterize over a wide range temperatures (dielectric spectroscopy) at microscopic length scales (neutron scattering). investigation evidences two relaxations associated with motions: fast process corresponding motions loosely bonded molecules slower amide–water complexes. While...

The rheological response, in particular the non-linear to oscillatory shear is experimentally investigated colloidal glasses. glasses are highly concentrated binary hard-sphere mixtures with relatively large size disparities. For a ratio of 0.2, strong reduction normalized elastic moduli, yield strain and stress and, for some samples, even melting glass fluid observed upon addition second species. This attributed more efficient packing, as indicated by shift random close packing larger total...

Abstract Mechanical properties are of central importance to materials sciences, in particular if they depend on external stimuli. Here we investigate the rheological response amorphous solids, namely colloidal glasses, forces. Using confocal microscopy and computer simulations, establish a quantitative link between macroscopic creep microscopic single-particle dynamics. We observe dynamical heterogeneities, regions enhanced mobility, which remain localized regime, but grow for applied...

Abstract The macroscopic properties of gels arise from their slow dynamics and load-bearing network structure, which are exploited by nature in numerous industrial products. However, a link between these structural dynamical has remained elusive. Here we present confocal microscopy experiments simulations gel-forming colloid–polymer mixtures. They reveal that gel formation is preceded continuous directed percolation. Both transitions lead to system-spanning networks, but only percolation...

Glasses exhibit a liquidlike structure but solidlike rheological response with plastic deformations only occurring beyond yielding. Thus, predicting the behavior from microscopic is difficult, important for materials science. Here, we consider colloidal suspensions and propose to supplement static structural information local dynamics, namely, rearrangement breaking of cage neighbors. This quantified by mean squared nonaffine displacement number particles that remain nearest neighbors long...

We present a simple new analytical method for educing the materials' linear viscoelastic properties, over widest range of experimentally accessible frequencies, from step-strain measurement, without need preconceived models nor idealization real measurements. This is achieved by evaluating Fourier transforms raw experimental data describing both time-dependent stress and strain functions. The novel has been implemented into an open access executable “i-Rheo,” enabling its use to broad...

Particle surface chemistry and internal softness are two fundamental parameters in governing the mechanical properties of dense colloidal suspensions, dictating structure flow, therefore interest from materials fabrication to processing.

Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation M. Laurati, S. U. Egelhaaf, G. Petekidis; Plastic rearrangements in colloidal gels investigated by LAOS LS-Echo. J. Rheol. 1 September 2014; 58 (5): 1395–1417. https://doi.org/10.1122/1.4872059 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex...

The binary hard-sphere mixture is one of the simplest representations a many-body system with competing time and length scales. This model relevant to fundamentally understand both structural dynamical properties materials, such as metallic melts, colloids, polymers bio-based composites. It also allows us study how different scales influence physical behavior multicomponent glass-forming liquid; question that still awaits unified description. In this contribution, we report on distinct...

We report the synthesis and characterization of poly (vinyl alcohol) (PVA)/Chitosan (CT) cryogels for applications involving uptake entrapment particulate bacterial colonies. In particular, we systematically investigated network pore structures gels as a function CT content different freeze-thaw times, combining Small Angle X-Ray Scattering (SAXS), Scanning Electron Microscopy (SEM), confocal microscopy. The nanoscale analysis obtained from SAXS shows that while characteristic correlation...

Starlike PEP-PEO block copolymer micelles offer the possibility to investigate phase behavior and interactions of regular star polymers (ultrasoft colloids). Micellar functionality f can be smoothly varied by changing solvent composition (interfacial tension). Structure factors obtained small-angle neutron-scattering quantitatively described in terms an effective potential for polymers. The experimental diagram reproduces a high level accuracy predicted liquid-solid transition. Whereas...

A combination of confocal microscopy and rheology experiments, Brownian dynamics (BD) molecular (MD) simulations mode coupling theory (MCT) have been applied in order to investigate the effect shear rate on transient stress–strain relations supercooled glassy systems under shear. Immediately after is switched on, microscopic display super-diffusion macroscopic a stress overshoot, which become more pronounced with increasing rate. MCT relates both negative sections generalized modulus, grow...

The transient response of model hard sphere glasses is examined during the application steady rate start-up shear using Brownian dynamics simulations, experimental rheology and confocal microscopy. With increasing strain, glass initially exhibits an almost linear elastic stress increase, a peak at yield point then reaches constant state. overshoot has nonmonotonic dependence with Peclet number, Pe, volume fraction, φ, determined by available free competition between structural relaxation...

Using confocal microscopy we investigate binary colloidal mixtures with large size asymmetry, in particular the formation of dynamically arrested states spheres. The volume fraction system is kept constant, and as concentration small spheres increased observe a series transitions to different states: an attractive glass, gel, asymmetric glass. These are distinguished by degree dynamical arrest amount structural heterogeneity. between two occur through melting fluid state. While...

Although solubilization of lipid membranes has been studied extensively, questions remain regarding the structural pathways and metastable structures involved. This study investigated whether non-ionic detergent Triton X-100 follows classical pathway or if intermediate nanostructures are formed.Small angle X-ray neutron scattering (SAXS/SANS) was used in combination with transmission electron cryo-microscopy cryo-tomography to deduce structure mixtures...

We investigate by means of small angle neutron scattering experiments and numerical simulations the interactions inter-particle arrangements concentrated dispersions copolymer microgels across volume phase transition (VPT).

Fluvial ecosystems are among the main drivers of microparticles (MPC) in form both synthetic polymers (i.e. microplastics; MPs) and natural-based textile fibers (MF