Time-Resolved Small-Angle X-ray Scattering Studies of Spinodal Decomposition Kinetics in a Semidilute Polystyrene−Dioctyl Phthalate Solution

Xie, Yonglin; Ludwig, Karl; Bansil, Rama; Gallagher, Patrick; Koňák, and Čestmír; Morales, G.

doi:10.1021/ma950153k

Cited by 11 publications

(5 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…50 The tendency to form clusters increases with increasing solute concentration and with decreasing temperature. Similar inhomogeneities were also observed in SAXS measurements on moderately concentrated polystyrene solutions in dioctylphthalate 51 and in cyclohexane. 52 The slow mode was also observed by Burchard 53 and Brown et al 54 Although the origin of this mode is not fully understood, it may reflect an association between chains.…”

Section: Figuresupporting

confidence: 79%

Dynamics of solutions of triblock copolymers in a selective solvent: Effect of varying copolymer concentration

Koňák

Fleischer

Tuzar

et al. 2000

J. Polym. Sci. B Polym. Phys.

Self Cite

View full text Add to dashboard Cite

Section: Figuresupporting

confidence: 79%

Dynamics of solutions of triblock copolymers in a selective solvent: Effect of varying copolymer concentration

Koňák

Fleischer

Tuzar

et al. 2000

J. Polym. Sci. B Polym. Phys.

Self Cite

View full text Add to dashboard Cite

“…Although further careful studies are required, this suggests the relevance of a two-fluid model. Similar analysis may also be applied to the early stage of phase separation of polymer systems [153][154][155].…”

Section: 12mentioning

confidence: 99%

Viscoelastic phase separation

Tanaka

2000

J. Phys.: Condens. Matter

553

718

View full text Add to dashboard Cite

Phase separation is one of the most fundamental phenomena that create spatially inhomogeneous patterns in materials and nature. It has so far been classified into three types: (i) solid, (ii) fluid, and (iii) viscoelastic phase separation [1]. The relevant transport processes are only diffusion for (i), diffusion and hydrodynamic convection for (ii), and diffusion, hydrodynamic convection, and mechanical stress for (iii). Here we discuss the physical mechanism of viscoelastic phase separation. This phase separation takes place universally if there is strong dynamic asymmetry between the components of a mixture. The origin of the dynamic asymmetry is either the size disparity between the components or the difference in the glass transition temperature between the components. For example, viscoelastic phase separation has been observed in polymer solutions, protein solutions [2], colloidal suspensions [3], and membrane systems [4]. Under a deep quench, a transient gel is formed by strong attractive interactions between the slower components. The connectivity of the network acts against phase separation and produces the mechanical stress in it. The coupling between the composition, velocity, and stress fields is the key to this phase separation. We also find phase-separation behaviour accompanying mechanical fracture [5]. Surprisingly, mechanical fracture becomes a dominant coarsening process of the phase separation. The behaviour of viscoelastic and fracture phase separation originates from a strong coupling between the composition and deformation field. We demonstrate that the same type of coupling between the density and deformation field leads to cavitation of fluid under shear and mechanical fracture of glassy liquids and solids under deformation [6]. We discuss a common physics underlying these apparently unrelated phenomena and a selection principle of the kinetic pathway of pattern evolution. For example, the only difference between phase separation and fracture may stem from whether deformation is produced internally by phase separation itself or externally by loading. The author thanks T. Araki, T. Koyama, Y. Nishikawa, and Y. Iwashita, and M. Tateno, for collaboration on viscoelastic phase separation and A. Furukawa for collaboration on cavitation and fracture.

show abstract

“…Although Okano et al 17 and others 18 have found full agreement with the O-Z behavior, experiments carried out in the semidilute regime of polymer solutions have shown deviations from the Ornstein-Zernike function. An "excess scattering" has been reported at low wavenumbers from polymeric solutions 1,[19][20][21][22][23][24] which is caused by the enhanced long wavelength concentration fluctuations in the system. It is not clear so far as to what causes this excess scattering.…”

Section: Theoretical Backgroundmentioning

confidence: 99%

Small-Angle Neutron Scattering Studies of Chemically Cross-Linked Gelatin Solutions and Gels

et al. 2001

View full text Add to dashboard Cite

Small-angle neutron scattering measurements are reported for experiments performed on mixtures of gelatin and glutaraldehyde (GA) in the aqueous phase, where the gelatin concentration was fixed at 5% (w/v) and the GA concentration was varied from 1.25 × 10 -4 to 3 × 10 -3 % (w/v). Two length scales associated with this system were identified in both sol (60°C) and gel state (28°C). One of these, the correlation length ( ) or mesh size of the cross-linked network showed negligible dependence on temperature, but a scaling ∼ [GA] ν , where [GA] is the concentration of cross-linker GA, was observed with ν ) 0.33 ( 0.04 in the gel state. Other length scale associated was the size of inhomogeneities which showed no [GA] dependence but showed appreciable increase in size as the system transformed from a sol to gel state for all [GA]. Observations are discussed in the context of the results obtained from dynamic light scattering experiments performed earlier.

show abstract

Time-Resolved Small-Angle X-ray Scattering Studies of Spinodal Decomposition Kinetics in a Semidilute Polystyrene−Dioctyl Phthalate Solution

Cited by 11 publications

References 25 publications

Dynamics of solutions of triblock copolymers in a selective solvent: Effect of varying copolymer concentration

Dynamics of solutions of triblock copolymers in a selective solvent: Effect of varying copolymer concentration

Viscoelastic phase separation

Small-Angle Neutron Scattering Studies of Chemically Cross-Linked Gelatin Solutions and Gels

Contact Info

Product

Resources

About