Polymerization in soft nanoconfinement of lamellar and reverse hexagonal mesophases

Qavi, Sahar; Bandegi, Alireza; Firestone, Millicent A.; Foudazi, Reza

doi:10.1039/c9sm01565e

Cited by 19 publications

(13 citation statements)

References 71 publications

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“…When these materials are extruded through a nozzle or die, the nano entities may become aligned in the flow direction, which produces a highly anisotropic macrostructure resulting in improved structure related properties. Such properties are of high interest in applications such as scaffolds for catalysis and separation, [ 17 ] templating, [ 18 ] encapsulation of molecules as drug delivery agents and nanocarriers, [ 19,20 ] or as media to obtain structural data of molecules. [ 21,22 ]…”

Section: Introductionmentioning

confidence: 99%

In Situ Visualization of the Structural Evolution and Alignment of Lyotropic Liquid Crystals in Confined Flow

Rodríguez-Palomo

Lutz‐Bueno

Cao

et al. 2021

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Self‐assembled materials such as lyotropic liquid crystals offer a wide variety of structures and applications by tuning the composition. Understanding materials behavior under flow and the induced alignment is wanted in order to tailor structure related properties. A method to visualize the structure and anisotropy of ordered systems in situ under dynamic conditions is presented where flow‐induced nanostructural alignment in microfluidic channels is observed by scanning small angle X‐ray scattering in hexagonal and lamellar self‐assembled phases. In the hexagonal phase, the material in regions with high extensional flow exhibits orientation perpendicular to the flow and is oriented in the flow direction only in regions with a high enough shear rate. For the lamellar phase, a flow‐induced morphological transition occurs from aligned lamellae toward multilamellar vesicles. However, the vesicles do not withstand the mechanical forces and break in extended lamellae in regions with high shear rates. This evolution of nanostructure with different shear rates can be correlated with a shear thinning viscosity curve with different slopes. The results demonstrate new fundamental knowledge about the structuring of liquid crystals under flow. The methodology widens the quantitative investigation of complex structures and identifies important mechanisms of reorientation and structural changes.

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Section: Introductionmentioning

confidence: 99%

In Situ Visualization of the Structural Evolution and Alignment of Lyotropic Liquid Crystals in Confined Flow

Rodríguez-Palomo

Lutz‐Bueno

Cao

et al. 2021

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“…The polymerization of the mesophases was performed in an oven at 70°C for 24 h. The monomer conversion in polyLLCs was approx. 90% 15 . As control samples, homogeneous mixtures of PEO/IL were prepared with the same ratio of PEO/IL as in the mesophase samples.…”

Section: Methodsmentioning

confidence: 99%

“…Several works have been reported on the morphology, ionic conductivity, glass transition temperature, and tensile strength of binary BCP/IL mixtures as function of the IL content 12,13 . In our previous work, we showed that polymerized LLCs (polyLLCs) of surfactant/water/oil and surfactant/IL/oil enable the formation of nanostructured polymers that exhibit enhanced mechanical strength while the original lamellar or hexagonal structure is retained after polymerization 14–16 . It has been suggested that by tuning the morphology and domain sizes of the self‐assembled structures, these materials could bypass the usual trade‐offs between mechanical strength and conductivity 17,18 .…”

Section: Introductionmentioning

confidence: 99%

Ion transport in polymerized lyotropic liquid crystals containing ionic liquid

Bandegi

Kim

Foudazi

2021

Journal of Polymer Science

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In this work, we investigate the effect of morphology and segmental dynamics on ion transport in polymerized lyotropic liquid crystals (polyLLCs) containing 1‐butyl‐3‐methylimidazolium tetrafluoroborate as ionic liquid (IL). We demonstrate that two important factors, which affect ion conduction in polyLLCs, are grain size and chain density at the interface. The polyLLC with large grain size (70 nm) shows significant reduction in ion conductivity (one order of magnitude) compared to its homopolymer/IL mixture. However, the polyLLC with small grain size (20 nm) has little difference in ion conductivity compared to its homopolymer/IL mixture. It is observed that decreasing the chain density enhances the interaction of IL with polymer chains and consequently slows the relaxation of polymer chains. In addition, comparing the dynamics of polymer chains in mixtures of homopolymer/IL and templated LLC mesophases shows that the confinement in LLC structure prolongs the relaxation of polymer chains.

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“…Porous polymers have many applications such as gas separation materials, , encapsulation agents for drug release, , membranes, − catalyst supports, , sensors, cell scaffolds, and electrode materials for energy storage, to name a few. The typical methods for making interconnected porous polymers include high internal phase emulsion (HIPE) templating, block copolymer self-assembly, , direct templating, and microfluidics . These methods can be cost-intensive when dealing with micrometer-sized void structures.…”

Section: Introductionmentioning

confidence: 99%

“…The major drawback to this process is the requirement of a template that is ultimately destroyed, limiting the scalability of the material. Self-assembly methods use block copolymer systems to produce ordered structures such as lyotropic liquid-crystalline phases, which can then be polymerized into a porous polymer . However, they are usually used to make mesoporous polymers with nanometer size pores.…”

Section: Introductionmentioning

confidence: 99%

Polyfoam: Foam-Templated Microcellular Polymers

Zowada

Foudazi

2020

Langmuir

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High internal phase emulsion (HIPE) templating has been developed as a robust method for the synthesis of porous polymers with designed porosity and void size. However, it has low starting material efficiency, requiring the removal of over 74% of the starting material to form interconnected porous structures. Foam templating methods attempt to resolve this issue by replacing the internal liquid phase with a gas phase. The current challenge for foam templating is to reach small void sizes (<100 μm), especially when using free-radical polymerization. We use a rapid gas dispersion method to form foam-templated hydrogels, which is an energy-effective method in comparison to the typical HIPE templating approach. We report hydrogels with an average void diameter of 63 μm at 70% porosity. The morphology and properties of foam-templated hydrogels are evaluated to show comparability to the HIPE-templated hydrogels of the same material.

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Polymerization in soft nanoconfinement of lamellar and reverse hexagonal mesophases

Abstract: The polymerization rate decreases in the nanoconfined structure compared to the bulk state due to the segregation effect, which increases the local monomer concentration and enhances the termination reaction.

Cited by 19 publications

References 71 publications

In Situ Visualization of the Structural Evolution and Alignment of Lyotropic Liquid Crystals in Confined Flow

In Situ Visualization of the Structural Evolution and Alignment of Lyotropic Liquid Crystals in Confined Flow

Ion transport in polymerized lyotropic liquid crystals containing ionic liquid

Polyfoam: Foam-Templated Microcellular Polymers

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