Disk-Shaped Bicelles in Block Copolymer/Homopolymer Blends

Greenall, M. J.

doi:10.1021/acs.macromol.5b02033

Cited by 3 publications

(5 citation statements)

References 75 publications

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“…Our observation of a limited growth of the disc-like micelles is in agreement with other studies 60 and recent theoretical considerations predicting conditions for their formation. 61 It is, however, not clear if the amphiphiles, which form spherical micelles on its own, are accumulated at the high curvature edges of the discs, 26,62,63 or if the two amphiphiles mix homogenously over the entire assembly. Although a reduction of the effective spontaneous curvature by mixing compounds of different molecular asymmetry provides the possibility of a morphological fine-tuning, a marked reduction to a value favoring extended bilayer structures was not observed.…”

Section: Discussionmentioning

confidence: 99%

Controlled self-assembly of stomatosomes by use of single-component fluorinated dendritic amphiphiles

et al. 2018

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A series of novel non-ionic amphiphiles with dendritic oligoglycerol head groups of different generations ([G1]-[G3]) and lipophilic/fluorophilic tail segments, comprising single or double tail alkyl chains, C8F17-perfluoro rod segments as well as flexible spacer groups of different lengths were designed and synthesized. We expected that the differences in the size of the dendritic head groups in combination with perfluorinated segments would have an impact on the supramolecular structures formed in aqueous solution if compared with the hydrogenated analogues. Investigating the self-assembly behavior mainly by cryogenic transmission electron microscopy (cryo-TEM) and cryo-electron tomography (cryo-ET) we found as a new result the formation of perforated bilayer vesicles (stomatosomes) and bicontinuous network structures. Surprisingly, we have observed stomatosome formation by self-assembly of single component fluorinated dendritic amphiphiles. These assembly structures turned out to be extremely robust against harsh conditions, although there are strong indications that they represent non-equilibrium structures, which eventually transform into a bicontinuous cubic network structure of double diamond symmetry. In general, the molecular asymmetry of amphiphiles tuned by chemical design induced the expected trend from spherical micelles through worm-like micelles to perforated bilayers and three-dimensional network structures.

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Section: Discussionmentioning

confidence: 99%

Controlled self-assembly of stomatosomes by use of single-component fluorinated dendritic amphiphiles

et al. 2018

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“…The stability of a diskshaped micelle under different proportions of DBC2 in the copolymer blend has been discussed by Greenall; so, a blend with 70% DBC1 and 30% DBC2 in the solvent is considered. 29 In Figure 1c, the cross section through the center of the micelle and in the normal direction of the substrate is obtained according to symmetry from the SCFT result. A disk-shaped micelle is absorbed on the substrate, and above it, there is a probe, which has a point-like shape.…”

Section: Resultsmentioning

confidence: 99%

“…Both the lamella-forming diblock DBC1 and the sphere-forming diblock DBC2 cannot self-assemble into a stable disk-shaped micelle alone in a selective solvent. The stability of a disk-shaped micelle under different proportions of DBC2 in the copolymer blend has been discussed by Greenall; so, a blend with 70% DBC1 and 30% DBC2 in the solvent is considered . In Figure c, the cross section through the center of the micelle and in the normal direction of the substrate is obtained according to symmetry from the SCFT result.…”

Section: Resultsmentioning

confidence: 99%

“…Greenall investigated the structure and stability of this micelle using SCFT, and its stability is compared with spherical, cylindrical, and lamellar aggregates. 29 The length of the hydrophilic block of the amphiphile is also a critical factor to the stability of disk-shaped micelles because micelles undergo a sequence of shape transitions from lamellar to cylindrical and then sphere as the hydrophilic block gets longer. 30 In this present work, we proposed a model system to study the effect of doped asymmetric phospholipid molecules on the mechanical response properties of micelles.…”

Section: Introductionmentioning

confidence: 99%

“…Amphiphilic block copolymers with long hydrophilic blocks and short hydrophilic blocks spontaneously self-assemble in a selective solvent to form disk-shaped micelles, which is a relatively rare form of self-assemblies as compared to cylindrical and spherical micelles. Greenall investigated the structure and stability of this micelle using SCFT, and its stability is compared with spherical, cylindrical, and lamellar aggregates . The length of the hydrophilic block of the amphiphile is also a critical factor to the stability of disk-shaped micelles because micelles undergo a sequence of shape transitions from lamellar to cylindrical and then sphere as the hydrophilic block gets longer …”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Regulation Mechanism of Bubbling Deformation and Fracture Toughness of the Membrane by Asymmetric Phospholipids: A Model System Study

Yang

Zhang

2020

Langmuir

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Dynamic regulation of the deformation modulus and fracture toughness of a membrane is critical to organelles and cells for matching their conflicting needs of resilient and fractured behaviors. These properties implement the protection of the function in the normal condition and the fission function in the endocytosis condition of a membrane. Naturally, a membrane contains phospholipids that have different hydrophilic and hydrophobic group length. The diffusion and aggregation of the phospholipids with asymmetry of the hydrophilic–hydrophobic ratio on the membrane play a key role in regulating the mechanical behaviors passively to the external force. In present work, the effects of the asymmetry of phospholipids on the bubbling deformation and fracture toughness of the membrane to external stretching are investigated in a model system. A disk-shaped micelle formed from the blend of symmetric and asymmetric diblock copolymers in a selective solvent is considered as the membrane sheet. Its mechanically responsive behaviors are investigated by self-consistent field theory. By analyzing the evolution of different components during the stretching process, the mechanism of formation of the bubbling structure is revealed. Moreover, the fracture toughness depending on the asymmetry of the phospholipids is determined quantitatively.

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One-step formulation of nonionic surfactant bicelles (NSBs) by a double-tailed polyglycerol-type nonionic surfactant

Aramaki

Iwata

Mata

et al. 2017

Phys. Chem. Chem. Phys.

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Bicelles are generally formed by phospholipid-based systems and are useful for various applications, such as nanocarriers or membrane protein crystallization. The same disc-like assemblies, nonionic surfactant bicelles (NSBs), can also be formed using nonionic amphiphiles, but this has not been reported extensively. We report a novel NSB system that employs the double-tailed nonionic amphiphile, polyglyceryl dialkyl ether (CCG), which has two alkyl chains and a polyglyceryl group. A symmetric-tail molecule, CCG, formed vesicles, whereas an asymmetric-tail molecule, CCG, formed NSBs through a simple one-step process using ultrasonication. The 1 wt% aqueous solution of CCG was in a two-phase equilibrium of a lamellar phase and a water phase. Transparent dispersion was obtained through ultrasonication treatment. The size distribution in the dispersion was obtained by dynamic light scattering (DLS), resulting in a narrow distribution of around 20 nm in diameter. A negatively-stained transmission electron microscopy (TEM) image showed oblong and spherical shapes, which are typically observed in bicelle-forming systems. A small angle neutron scattering (SANS) measurement well proved bicelle formation by fitting a core-shell bicelle form factor model. The disc thickness and diameter were in agreement with the values obtained by DLS and TEM, respectively. A larger shell thickness at the rim part than at the flat disc part suggested that NSB aggregates have inhomogeneous molecular distribution. Similar to phospholipid systems, the bicelle-forming CCG system produced a defective lamellar phase formation at high surfactant concentrations, whereas a general lamellar phase was formed in the vesicle-forming CCG system.

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Disk-Shaped Bicelles in Block Copolymer/Homopolymer Blends

Cited by 3 publications

References 75 publications

Controlled self-assembly of stomatosomes by use of single-component fluorinated dendritic amphiphiles

Controlled self-assembly of stomatosomes by use of single-component fluorinated dendritic amphiphiles

Regulation Mechanism of Bubbling Deformation and Fracture Toughness of the Membrane by Asymmetric Phospholipids: A Model System Study

One-step formulation of nonionic surfactant bicelles (NSBs) by a double-tailed polyglycerol-type nonionic surfactant

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