Applications of shear-induced polarized light imaging (SIPLI) technique for mechano-optical rheology of polymers and soft matter materials

Mykhaylyk, Oleksandr O.; Warren, Nicholas J.; Parnell, Andrew J.; Pfeifer, Gerhard; Laeuger, Joerg

doi:10.1002/polb.24111

Cited by 47 publications

(77 citation statements)

References 52 publications

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“…Indeed, a characteristic Maltese cross appeared in the polarized light images ( Figure 11 b) at 26 °C, which indicated birefringence caused by worm alignment under shear. 61 The observations roughly correspond to those in the temperature-dependent SAXS study, where a population of relatively long worms (contour length >2000 nm) is detected between 20 and 25 °C.…”

Section: Resultssupporting

confidence: 84%

“…This recently commercialized instrument has been described in detail elsewhere. 61 The measurements were performed using a plate–plate geometry composed of a 25 mm polished steel top plate and a fused quartz bottom plate coupled with a variable temperature Peltier system. The gap between plates d gap was set at 1.0 mm for all experiments.…”

Section: Experimental Sectionmentioning

confidence: 99%

“… 60 More recently, SIPLI has been used to demonstrate that G x -H y worms can be aligned under shear and also to obtain characteristic worm relaxation times after cessation of shear. 61 …”

Section: Introductionmentioning

confidence: 99%

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Critical Dependence of Molecular Weight on Thermoresponsive Behavior of Diblock Copolymer Worm Gels in Aqueous Solution

et al. 2018

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Reversible addition–fragmentation chain transfer (RAFT) aqueous dispersion polymerization of 2-hydroxypropyl methacrylate was used to prepare three poly(glycerol monomethacrylate)x–poly(2-hydroxypropyl methacrylate)y (denoted Gx-Hy or PGMA-PHPMA) diblock copolymers, namely G37-H80, G54-H140, and G71-H200. A master phase diagram was used to select each copolymer composition to ensure that a pure worm phase was obtained in each case, as confirmed by transmission electron microscopy (TEM) and small-angle x-ray scattering (SAXS) studies. The latter technique indicated a mean worm cross-sectional diameter (or worm width) ranging from 11 to 20 nm as the mean degree of polymerization (DP) of the hydrophobic PHPMA block was increased from 80 to 200. These copolymer worms form soft hydrogels at 20 °C that undergo degelation on cooling. This thermoresponsive behavior was examined using variable temperature DLS, oscillatory rheology, and SAXS. A 10% w/w G37-H80 worm dispersion dissociated to afford an aqueous solution of molecularly dissolved copolymer chains at 2 °C; on returning to ambient temperature, these chains aggregated to form first spheres and then worms, with the original gel strength being recovered. In contrast, the G54-H140 and G71-H200 worms each only formed spheres on cooling to 2 °C, with thermoreversible (de)gelation being observed in the former case. The sphere-to-worm transition for G54-H140 was monitored by variable temperature SAXS: these experiments indicated the gradual formation of longer worms at higher temperature, with a concomitant reduction in the number of spheres, suggesting worm growth via multiple 1D sphere–sphere fusion events. DLS studies indicated that a 0.1% w/w aqueous dispersion of G71-H200 worms underwent an irreversible worm-to-sphere transition on cooling to 2 °C. Furthermore, irreversible degelation over the time scale of the experiment was also observed during rheological studies of a 10% w/w G71-H200 worm dispersion. Shear-induced polarized light imaging (SIPLI) studies revealed qualitatively different thermoreversible behavior for these three copolymer worm dispersions, although worm alignment was observed at a shear rate of 10 s–1 in each case. Subsequently conducting this technique at a lower shear rate of 1 s–1 combined with ultra small-angle x-ray scattering (USAXS) also indicated that worm branching occurred at a certain critical temperature since an upturn in viscosity, distortion in the birefringence, and a characteristic feature in the USAXS pattern were observed. Finally, SIPLI studies indicated that the characteristic relaxation times required for loss of worm alignment after cessation of shear depended markedly on the copolymer molecular weight.

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Section: Resultssupporting

confidence: 84%

Section: Experimental Sectionmentioning

confidence: 99%

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Critical Dependence of Molecular Weight on Thermoresponsive Behavior of Diblock Copolymer Worm Gels in Aqueous Solution

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“…† This opto-rheological technique has been recently used to demonstrate the alignment of anisotropic nano-objects such as block copolymer worms and lamellae at a certain critical rate of applied shear. 57 Thus, the SIPLI image recorded under continuous shear ow at 3 C appears dark (see Fig. S4 †); this is consistent with the presence of isotropic spheres, which cannot be aligned.…”

Section: Resultssupporting

confidence: 55%

Unique aqueous self-assembly behavior of a thermoresponsive diblock copolymer

et al. 2020

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“…10 Pa. To our knowledge, this kind of viscosity behavior has not been reported earlier for MFC suspensions. Such abrupt change in the rheological behavior of the MFC suspension is likely to be related with a sudden structural change in the suspension, for example, in fibre orientation [31] and/or flocculation [28]. For the floc size analysis, 50 images consisting of 1000 successive A-scans were analysed for the amplitude signals.…”

Section: Appl Sci 2018 8 X For Peer Review 5 Of 11mentioning

confidence: 99%

Rheological and Flocculation Analysis of Microfibrillated Cellulose Suspension Using Optical Coherence Tomography

et al. 2018

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A sub-micron resolution optical coherence tomography device was used together with a pipe rheometer to analyze the rheology and flocculation dynamics of a 0.5% microfibrillated cellulose (MFC) suspension. The bulk behavior of the MFC suspension showed typical shear thinning (power-law) behavior. This was reflected in a monotonously decreasing floc size when the shear stress exceeded the yield stress of the suspension. The quantitative viscous behavior of the MFC suspension changed abruptly at the wall shear stress of 10 Pa, which was reflected in a simultaneous abrupt drop of the floc size. The flocs were strongly elongated with low shear stresses. With the highest shear stresses, the flocs were almost spherical, indicating a good level of fluidization of the suspension.

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Applications of shear-induced polarized light imaging (SIPLI) technique for mechano-optical rheology of polymers and soft matter materials

Cited by 47 publications

References 52 publications

Critical Dependence of Molecular Weight on Thermoresponsive Behavior of Diblock Copolymer Worm Gels in Aqueous Solution

Critical Dependence of Molecular Weight on Thermoresponsive Behavior of Diblock Copolymer Worm Gels in Aqueous Solution

Unique aqueous self-assembly behavior of a thermoresponsive diblock copolymer

Rheological and Flocculation Analysis of Microfibrillated Cellulose Suspension Using Optical Coherence Tomography

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