Nature of Viscoelasticity in Lamellar Block Copolymers: Contraction Correlated to Strain Localization

Polis, Daniel L.; Winey, Karen I.; Ryan, Anthony J.; Smith, Steven D.

doi:10.1103/physrevlett.83.2861

Cited by 19 publications

(13 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Its viscosity could not be determined (with the instrument used) below a temperature of about 85 C. The mechanisms responsible for the rather low fluidity of ZMeImI could include various effects of molecular weight, 28 tail length, 21 as well as microstructure formation (microphase separation) in the fluid. [29][30][31] To explore the first two possibilities, the viscosities of ZMeImI were measured at 85-95 C, where the sample attained a more fluid state to permit such measurements. The results were then compared with the liquid phase viscosities, measured at the same temperatures, for another group of PEGylated ILs (cf.…”

Section: Viscosity Measurementsmentioning

confidence: 99%

Ionic liquids with fluorinated block-oligomer tails: Influence of self-assembly on transport properties

Ganapatibhotla

Zheng

et al. 2011

J. Mater. Chem.

View full text Add to dashboard Cite

A novel imidazolium iodide ionic liquid with an u-perfluoroalkyl poly(ethylene glycol) (PEG) tail attached to the imidazolium ring has been synthesized for its potential incorporation as an electrolyte in dye-sensitized solar cells. The ionic liquid molecules, with block oligomer tails, self-assembled to form a solvent-free ionic gel, without the assistance of an external gelator or an immobilizing matrix. The solidification was evidently facilitated by the generation of ionic clusters due to electrostatic interactions, as well as microphase separation of the immiscible perfluoroalkyl and PEG segments of the cation. We report herein the synthesis and electrochemical properties of this block oligomer ionogel, along with the results of self-consistent mean field calculations probing the formation of nanostructures in the ionogel. Although properties such as high viscosity and high ionic conductivity appear incompatible, it is shown that a nano-structured fluid can support high iodide diffusion at low effective fluidity, and that the formation of an organic alloy, by simple blending of two imidazolium iodide salts, can produce significant conductivity enhancements without lowering the viscosity.

show abstract

Section: Viscosity Measurementsmentioning

confidence: 99%

Ionic liquids with fluorinated block-oligomer tails: Influence of self-assembly on transport properties

Ganapatibhotla

Zheng

et al. 2011

J. Mater. Chem.

View full text Add to dashboard Cite

show abstract

“…We suggest that the delamination is the result of both disentanglement and normal forces. Lamellar contraction is known to occur during shear deformation 19 and could give rise to the necessary normal forces for delamination upon cooling. 20…”

Section: Effect Of Strain On Kink Band Morphology Andmentioning

confidence: 99%

Evolution of Kink Bands and Tilt Boundaries in Block Copolymers at Large Shear Strains

Qiao

Winey

2000

Macromolecules

View full text Add to dashboard Cite

The evolution of kink bands and kink band boundaries in a prealigned poly(styrene-bethylene propylene) lamellar diblock copolymer was investigated by applying steady shear at strains in the range of 1-10 strain units. Boundary morphologies were characterized using transmission electron microscopy. As the shear strain increases, both the kink bands and the lamellae within the kink bands rotate continuously toward the shearing direction, leading to a decrease in the tilt boundary angle and the kink band boundary angle. Simultaneously, the nature of the kink band boundary transforms. The chevron boundaries present at low strains, and thus large tilt angles, become omega boundaries as the strain increases to ∼3 strain units. At higher strains (∼5 strain units), the tilt angle further decreases, and the omega boundaries start to break, preferentially in the PS microdomains. Delamination of the PS microdomains was also observed at the highest strain amplitude (10 strain units), which was associated with the limited extent of entanglement across the PS microdomains.

show abstract

“…There have been several discussions of the effect of flow on the layer spacing in block copolymer lamellar systems, which focus on the change in polymer conformations due to the stretching imposed by flow in melts and solutions [42], and layer changes have been reported in melts [45]. Our mechanism is unrelated to this one, but may be related to recent experiments on block copolymer solutions that have demonstrated a change in layer spacing [46] and onion formation as a function of flow [19], if those systems are Helfrich stabilised.…”

Section: Introduction and Overviewmentioning

confidence: 99%

The effect of shear flow on the Helfrich interaction in lyotropic lamellar systems

Marlow

Olmsted

2002

Eur. Phys. J. E

View full text Add to dashboard Cite

We study the effect of shear flow on the entropic Helfrich interaction in lyotropic surfactant smectic fluids. Arguing that flow induces an effective anisotropic surface tension in bilayers due to a combination of intermonolayer friction, bilayer collisions and convection, we calculate the reduction in fluctuations and hence the renormalised change in effective compression modulus and steady-state layer spacing. We demonstrate that non-permeable or slowly permeating membranes can be susceptible to an undulatory instability of the Helfrich-Hurault type, and speculate that such an instability could be one source of a transition to multilamellar vesicles.

show abstract

Nature of Viscoelasticity in Lamellar Block Copolymers: Contraction Correlated to Strain Localization

Cited by 19 publications

References 12 publications

Ionic liquids with fluorinated block-oligomer tails: Influence of self-assembly on transport properties

Ionic liquids with fluorinated block-oligomer tails: Influence of self-assembly on transport properties

Evolution of Kink Bands and Tilt Boundaries in Block Copolymers at Large Shear Strains

The effect of shear flow on the Helfrich interaction in lyotropic lamellar systems

Contact Info

Product

Resources

About