Formation of Network and Cellular Structures by Viscoelastic Phase Separation

Tanaka, Hajime

doi:10.1002/adma.200802763

Cited by 72 publications

(79 citation statements)

References 74 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, in the PS/PVME/SiO 2 (10/90/4) blend, the mobility of the original fast PVME‐rich phase was arrested by the SiO 2 nanoparticles and made the original slow phase (PS‐rich phase) become the fast one. Accordingly, there is a substantial decrease in the deformation rate of domains,42 which slows down the whole coarsening process of the phase separation. Moreover, the PVME‐rich phase became the slow component while the PS‐rich phase had a fast relaxation process.…”

Section: Resultsmentioning

confidence: 99%

Morphological Transition Induced by Nanoparticles in Dynamically Asymmetric PS/PVME Blends

Xia

Huang

Peng

et al. 2010

Macro Chemistry & Physics

View full text Add to dashboard Cite

The influence of hydrophilic SiO2 nanoparticles on the morphology of polystyrene (PS)/poly(vinyl methyl ether) (PVME) (10/90) blends in an unstable region has been investigated using optical microscopy and dynamic rheology techniques. For PS/PVME (10/90) blends annealed at 120 °C, the formation of a transient network structure and subsequent phase inversion indicates that a typical viscoelastic phase separation has occurred. However, for PS/PVME (10/90) blends filled with 4 wt.‐% SiO2 nanoparticles, a droplet‐like structure was formed immediately without the appearance of a network‐like structure. The rheological relaxation time of the blends suggested that the morphology transition observed in the PS/PVME/SiO2 (10/90/4) blend was related to the change in the dynamic asymmetry between the PS‐rich phase and the PVME‐rich phase, which was induced by the selective affinity of the SiO2 nanoparticles for PVME. After the incorporation of SiO2 nanoparticles, the PVME‐rich majority phase, which is originally the dynamically fast phase, became the slow phase, and led to a dynamic inversion compared with those unfilled blends.

show abstract

Section: Resultsmentioning

confidence: 99%

Morphological Transition Induced by Nanoparticles in Dynamically Asymmetric PS/PVME Blends

Xia

Huang

Peng

et al. 2010

Macro Chemistry & Physics

View full text Add to dashboard Cite

show abstract

“…First we emphasize that pattern evolution in viscoelastic phase separation is essentially the same between the two types of dynamically asymmetric mixtures: 11,13,14 one is a system like polymer solutions, [5][6][7]64 colloidal suspensions, 65 and protein solutions, 66 where the strong dynamic asymmetry comes from a large difference in the molecular size and topology between the components, and the other is a system whose components have a large difference in the glass transition temperature. 8 In both cases, a mixture first becomes cloudy just after the temperature quench, then, after some incubation time, small solvent holes start to appear (see Fig.…”

Section: General Featuresmentioning

confidence: 99%

Viscoelastic phase separation in soft matter and foods

Tanaka

2012

Faraday Discuss.

Self Cite

View full text Add to dashboard Cite

Phase separation is a fundamental phenomenon that produces spatially heterogeneous patterns in soft matter and foods. We argue that phase separation in these materials generally belongs to "viscoelastic phase separation", where the morphology is determined by the mechanical balance of not only the thermodynamic force (interface tension) but also the viscoelastic force. The origin of the viscoelastic force is dynamic asymmetry between the components of a mixture, which can be caused by either a size disparity or a difference in the glass transition temperature between the components. Such dynamic asymmetry quite often exists in foods, which are typically mixtures of big molecules (polymers, proteins, etc.) and liquids (water, oil, etc.). We show examples of mechanically driven pattern formation in foods, in which dynamic asymmetry plays crucial roles, including the formation of network and cellular patterns in foods (e.g., breads, sponge cakes, butter, chocolates, etc.) and crack pattern formation (dried foods, cooked meat, etc.). Collapsing of these structures upon heating or moisture uptake is also discussed. We also argue that heterogeneous gels are in general formed as a consequence of dynamical arrest of the viscoelastic phase separation. Finally we mention an intimate link of viscoelastic phase separation, where deformation fields are spontaneously generated by phase separation itself, to mechanical instability and fracture induced by externally imposed strain fields. Such mechanical instability and nonlinear rheology may be relevant to food processing and also to separation and fracture of foods. We propose that all these phenomena can be understood as mechanically driven inhomogeneization with the concept of dynamic asymmetry in a unified manner.

show abstract

“…Because ultimate performance of blended materials is mainly determined by the formed structures, many studies on curing reaction, rheology, and morphology evolution have been carried out detailedly . Among these, an unusual viscoelastic phase separation founded by Tanaka et al has been paid some attention in recent years . With much larger size or higher glass‐transition temperature ( T g ), the evolution of slow dynamic component normally falls behind the rate of phase separation, leading to the volume shrinking phenomenon and transient network or sponge‐like structure formation.…”

Section: Introductionmentioning

confidence: 99%

Effect of cellulose nanofiber on the dynamically asymmetric phase separation in epoxy/polysulfone blends

Zhang

Ling

Zhao

et al. 2019

J Polym Sci B Polym Phys

View full text Add to dashboard Cite

Significant effect of cellulose nanofibers (CNFs) on cure‐induced phase separation in dynamically asymmetric system is reported. An epoxy/polysulfone blends with typical layered structure formation was chosen as the polymer matrix, and morphology evolution and rheological behavior of systems with different nano‐size fiber loadings upon curing reaction were investigated using optical microscopy and rheological measurement. CNF distributed uniformly in the polymer matrix and had good interaction with polymer chains. Curing reaction of epoxy was promoted by CNF, making the system gel and phase separate earlier. Meanwhile, system viscosity was increased with CNF addition, and the movement of polymer chains and component diffusion were constrained, as a result, the structure evolution process was slowed down. The CNF altered the final morphologies, resulting in refined structures with smaller characteristic length scales or even completely change the morphologies from the layered structures to a bicontinuous structure when the CNF concentration reached to a relatively high level. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 1357–1366

show abstract

Formation of Network and Cellular Structures by Viscoelastic Phase Separation

Cited by 72 publications

References 74 publications

Morphological Transition Induced by Nanoparticles in Dynamically Asymmetric PS/PVME Blends

Morphological Transition Induced by Nanoparticles in Dynamically Asymmetric PS/PVME Blends

Viscoelastic phase separation in soft matter and foods

Effect of cellulose nanofiber on the dynamically asymmetric phase separation in epoxy/polysulfone blends

Contact Info

Product

Resources

About