Dynamic Light Scattering from Dilute, Semidilute, and Concentrated Block Copolymer Solutions

Pan, Chuanbin; Maurer, Wayne W.; Liu, Z.; Lodge, Timothy P.; Štěpánek, Petr; Meerwall, E. D. von; Watanabe, Hiroshi

doi:10.1021/ma00109a042

Cited by 68 publications

(65 citation statements)

References 24 publications

(50 reference statements)

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“…We found dn/dc ) 0.023 mL/g, while for the previously discussed case of SV-50 in THF we have dn/dc ) 0.110 mL/g. Accordingly, the heterogeneity mode 4 for the toluene solution has a higher relative amplitude than in the case of THF (as has been previously shown 12,48 ), and the same holds for modes 1 and 2. The relaxation time of the heterogeneity mode τ H is related to the self-diffusion coefficient D s of an A-B diblock copolymer by 46,47 where is the interaction parameter between the two polymer blocks A and B and κ ) 2δf 2 (1 -f ) 2 /(f 2 + (1 -f ) 2 ), with f being the fraction of A blocks and δ ) (M w /M n ) -1.…”

Section: Resultssupporting

confidence: 69%

“…[8][9][10] Important examples are the following: (1) In dilute solutions: translational diffusion of polymer coils, internal mode of homopolymer, 11 or diblock copolymer chains. 12,46,47 (2) In semidilute solutions: cooperative diffusion of the transient polymer network, heterogeneity mode related to polymer self-diffusion (in diblock copolymers), 12,13,17,46,47 entanglement mode, 14 chain reptation, 14,15 viscoelastic relaxation, 16 diffusion of clusters. 13,17,18,36 Rouse modes have been predicted theoretically 19 and observed experimentally.…”

Section: Introductionmentioning

confidence: 99%

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A Dynamic Light Scattering Study of Fast Relaxations in Polymer Solutions

et al. 2007

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We have analyzed the fine structure of the distribution of relaxation times obtained from dynamic light scattering on solutions of homopolymers and diblock copolymers. We have shown that in a carefully designed experiment two additional fast modes can be identified in the distribution of relaxation times, besides the usual cooperative mode, heterogeneity mode, and cluster mode. We have shown that the faster of these two modes, well observable only at small angles, is due to the thermal diffusion coefficient of the solvent. For the slower of these two modes, several experimental findings lead to the conclusion that this mode is representative of the motion of the solvent molecules in the solution.

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Section: Resultssupporting

confidence: 69%

Section: Introductionmentioning

confidence: 99%

A Dynamic Light Scattering Study of Fast Relaxations in Polymer Solutions

et al. 2007

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“…Some experimental studies have been reported on dilute, semi-dilute, and concentrated solutions of random and block copolymers. [107,108] …”

Section: Coil-globule Transition Of Copolymersmentioning

confidence: 99%

Coil‐Globule Collapse in Flexible Macromolecules

Baysal

Karasz

2003

Macro Theory & Simulations

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The transition of a solvated flexible macromolecular chain from random coil behavior in the θ‐state to a globular compact form in the collapsed state has been the subject of extensive theoretical and experimental studies. Most of the coil‐globule transition studies of macromolecules have concentrated on the prototypical polystyrene‐cyclohexane system. However, chain contractions reported in this system have been around 75% of those in the unperturbed θ‐state. This relatively small decrease in size does not satisfy the criterion for a densely packed, collapsed globule. Experimentally, the collapse from a coil to a true compact globular state has now been established for two flexible macromolecules: poly(N‐isopropylacrylamide) in water and poly(methyl methacrylate) in various solvents. In this contribution, we review recent theoretical studies covering phenomenological and Langevin models as well as computer simulations. In addition, we outline recent experimental studies of the coil‐globule transition of various flexible polymers, copolymers, and polyelectrolytes.Expansion factor, α, versus temperature for NaPSS in 4.17 M aqueous NaCl solution. (•): NaPSS‐1, (○): NaPSS‐2.imageExpansion factor, α, versus temperature for NaPSS in 4.17 M aqueous NaCl solution. (•): NaPSS‐1, (○): NaPSS‐2.

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“…5,6,9,28,29 This system is particularly well suited to explore the OOT and ODT behavior due to the presence of a birefringent phase (C) positioned between two isotropic phases (G and D). Figure 4 presents the temperature dependence of the depolarized transmitted intensity for the identical concentrations as in Figure 3.…”

Section: Neutral Solvent Phase Behaviormentioning

confidence: 99%

Effect of dilution on a block copolymer in the complex phase window

Hanley

Lodge

1998

J. Polym. Sci. B Polym. Phys.

111

180

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The phase behavior of a styrene–isoprene (SI) diblock copolymer, with block molecular weights of 1.1 × 104 and 2.1 × 104 g/mol, respectively, is examined in the neutral solvent bis(2‐ethylhexyl) phthalate (DOP) and the styrene‐selective solvent di‐n‐butyl phthalate (DBP). DBP is a good solvent for PS, but is near a theta solvent for PI at approximately 90°C. Small‐angle X‐ray scattering (SAXS), rheology, and static birefringence are used to locate and identify order–order (OOT) and order–disorder transitions (ODT); all three techniques gave consistent results. The neat polymer adopts the gyroid (G) phase at low temperatures, with an OOT to hexagonally‐packed cylinders (C) at 185°C, and the ODT at 238°C. Upon dilution with the neutral solvent DOP, the C window is diminished, until for a polymer concentration ϕ = 0.65, a direct G to disorder (D) ODT is observed. These results reflect increased stability of the disordered state, based on the different concentration scalings of the interaction parameter, χ, at the OOT and ODT. The OOT follows the dilution approximation, i.e., χOOT ∼ ϕ−1, but the ODT is found to follow a stronger concentration dependence, i.e., χODT ∼ ϕ−1.4, similar to the scaling of ϕ−1.6 found previously for lamellar SI diblocks in toluene and DOP. Addition of the selective solvent DBP produces dramatic changes in the phase behavior relative to DOP and the melt state; these include transitions to lamellar (L) and perforated layer (PL) structures. The observed phase sequences can be understood in terms of trajectories across the SI melt phase map (temperature vs. composition): addition of a neutral solvent or increasing temperature corresponds to a “vertical” trajectory, whereas adding a selective solvent amounts to a “horizontal” trajectory. When the solvent selectivity depends on temperature, as it does for the SI/DBP system, increasing temperature results in a diagonal trajectory. For both neutral and selective solvents the domain spacing, d*, scales with ϕ and χ as anticipated by self‐consistent mean‐field theory. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 3101–3113, 1998

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Dynamic Light Scattering from Dilute, Semidilute, and Concentrated Block Copolymer Solutions

Cited by 68 publications

References 24 publications

A Dynamic Light Scattering Study of Fast Relaxations in Polymer Solutions

A Dynamic Light Scattering Study of Fast Relaxations in Polymer Solutions

Coil‐Globule Collapse in Flexible Macromolecules

Effect of dilution on a block copolymer in the complex phase window

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