On the wall slip phenomenon of elastomers in oscillatory shear measurements using parallel-plate rotational rheometry: I. Detecting wall slip

Walter, Bastian; Pelteret, Jean-Paul; Kaschta, Joachim; Schubert, Dirk W.; Steinmann, Paul

doi:10.1016/j.polymertesting.2017.05.035

Cited by 24 publications

(17 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Wall slip can be revealed from the raw waveform data or normalized Lissajous figures. 30,32 This is not, however, unambiguous, because yielding has a similar effect on the stress waveform. 33,34 Slippage can also be observed in the maximum of loss modulus (G′′) upon increasing strain/stress.…”

mentioning

confidence: 93%

“…Sample preparation and different geometries influence the results in the nonlinear viscoelastic regime. 30 Therefore, three different geometries were used for rheology: (i) a smooth parallel plate, (ii) cross-hatched parallel plate, and (iii) cone and plate (smooth). We used 5.0 mg/mL aq.…”

mentioning

confidence: 99%

“…This is relevant, as the wall slip results in an incomplete force transfer to the sample, leading to erroneous and unreliable data. Wall slip can be revealed from the raw waveform data or normalized Lissajous figures. , This is not, however, unambiguous, because yielding has a similar effect on the stress waveform. , Slippage can also be observed in the maximum of loss modulus ( G′′ ) upon increasing strain/stress. At this point the stress waveform deviates from a sinusoidal response with the two “additional peaks” .…”

mentioning

confidence: 99%

See 2 more Smart Citations

Strain-Stiffening of Agarose Gels

Bertula

Martikainen

Munne³

et al. 2019

ACS Macro Lett.

107

View full text Add to dashboard Cite

Strain-stiffening is one of the characteristic properties of biological hydrogels and extracellular matrices, where the stiffness increases upon increased deformation. Whereas strain-stiffening is ubiquitous in protein-based materials, it has been less observed for polysaccharide and synthetic polymer gels. Here we show that agarose, that is, a common linear polysaccharide, forms helical fibrillar bundles upon cooling from aqueous solution. The hydrogels with these semiflexible fibrils show pronounced strain-stiffening. However, to reveal strain-stiffening, suppressing wall slippage turned as untrivial. Upon exploring different sample preparation techniques and rheological architectures, the cross-hatched parallel plate geometries and in situ gelation in the rheometer successfully prevented the slippage and resolved the strain-stiffening behavior. Combining with microscopy, we conclude that strain-stiffening is due to the semiflexible nature of the agarose fibrils and their geometrical connectivity, which is below the central-force isostatic critical connectivity. The biocompatibility and the observed strain-stiffening suggest the potential of agarose hydrogels in biomedical applications.

show abstract

mentioning

confidence: 93%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Strain-Stiffening of Agarose Gels

Bertula

Martikainen

Munne³

et al. 2019

ACS Macro Lett.

107

View full text Add to dashboard Cite

show abstract

“…Furthermore, in dynamic rheology experiments at 200 °C, the sample was found to be tacky, adhering well to the plates, which is crucial for the no slip condition. The absence of the Newtonian plateau in both dynamic and shear rheology plots of the blends, the tacky nature of the samples during dynamic rheology experiments and the absence of breaks in the rheological curves indicate the no slip condition [ 56 , 57 ]. Hence, the possibility of experimental error has been ruled out.…”

Section: Resultsmentioning

confidence: 99%

Microstructure Development and Its Influence on the Properties of Styrene-Ethylene-Butylene-Styrene/Polystyrene Blends

2018

View full text Add to dashboard Cite

Abstract:The present work is a novel attempt to understand the microstructure of styrene-ethylenebutylene-styrene (SEBS)/polystyrene (PS) blends not only through morphological studies, but also thermal, mechanical and rheological characterizations. SEBS/PS blends containing 10, 30 and 50 wt % PS were processed in a micro-compounder and characterized. Scanning electron microscopy (SEM) studies, with selective staining of the PS phase, revealed the presence of PS as nanometer-sized domains, as well as phase-separated micrometer-sized aggregates. Blends with 30 and 50 wt % PS exhibited a fibrillar microstructure, obeying Hirsch's model of short fiber composites. A remarkable increase in glass transition temperature indicated a strong interaction of the fibrils with SEBS. All blends showed two modes of relaxation corresponding to the two phases. A single mode of relaxation of the PS phase has been attributed to combined effects of the partial miscibility of the added PS, along with the interaction of the fibrils with SEBS. The long relaxation time of the elastomeric phase indicated the tendency of these materials to undergo time-dependent shrinkage in secondary processing operations. An increase in PS content resulted in the lowering of the shear viscosity and energy requirement for mixing, indicating the ease of processing.

show abstract

“…The angular velocity of the oscillations was chosen as 2 rad/s. In addition, the sticky nature of the sample prevents slippage at the sample-machine interfaces [74,75,72]. Shear hysteresis loops in Fig.…”

Section: Constant Oscillatory Shearmentioning

confidence: 99%

Effects of soft and hard magnetic particles on the mechanical performance of ultra-soft magnetorheological elastomers

Moreno-Mateos

López-Donaire

Hossain

et al. 2022

Smart Mater. Struct.

View full text Add to dashboard Cite

Magnetorheological elastomers (MREs) mechanically respond to external magnetic stimuli by changing their mechanical properties and/or changing their shape. Recent studies have shown the great potential of MREs when manufactured with an extremely soft matrix and soft-magnetic particles. Under the application of an external magnetic field, such MREs present significant mechanical stiffening, and when the magnetic field is off, they show a softer response, being these alternative states fully reversible. Although soft-magnetic particles are suitable for their high magnetic susceptibility, they require the magnetic actuation to remain constant in order to achieve the magneto-mechanical stiffening. Here, we present an alternative solution based on hard-magnetic MREs to provide stiffening responses that can be sustained along time without the need of keeping the external magnetic field on. To this end, we manufacture novel extremely soft hard-magnetic MREs (stiffness in the order of 1~kPa) and characterise them under magneto-mechanical shear and confined magnetic expansion deformation modes, providing a comparison framework with the soft-magnetic counterparts. The extremely soft nature of the matrix allows for easily activating the magneto-mechanical couplings under external magnetic actuation. In this regard, we provide a novel approach by setting the magnetic actuation below the fully magnetic saturating field. In addition, free deformation tests provide hints on the microstructural transmission of torques from the hard-magnetic particles to the viscoelastic carrier matrix, resulting in macroscopic geometrical effects and complex functional morphological changes.

show abstract

On the wall slip phenomenon of elastomers in oscillatory shear measurements using parallel-plate rotational rheometry: I. Detecting wall slip

Cited by 24 publications

References 39 publications

Strain-Stiffening of Agarose Gels

Strain-Stiffening of Agarose Gels

Microstructure Development and Its Influence on the Properties of Styrene-Ethylene-Butylene-Styrene/Polystyrene Blends

Effects of soft and hard magnetic particles on the mechanical performance of ultra-soft magnetorheological elastomers

Contact Info

Product

Resources

About