Twist grain boundaries in cubic surfactant phases

Belushkin, Maxim; Gompper, Gerhard

doi:10.1063/1.3096987

Cited by 9 publications

(10 citation statements)

References 43 publications

(63 reference statements)

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Section: Numerical Modelling Of Minimal and Cmc Twinssupporting

confidence: 79%

“…Note that the deviations are only prominent in the vicinity of the twin boundary and decay fast within a short distance. In fact, a similar decay has also been reported for a simulated twist grain boundary in LLC within the Ginzburg-Landau scheme (Belushkin & Gompper, 2009). It is interesting to note that the opposite sides of the partitioning layer can be asymmetric, hence one side can be more strongly perturbed by twinning than the other.…”

Section: Numerical Modelling Of Minimal and Cmc Twinssupporting

confidence: 76%

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Crystal twinning of bicontinuous cubic structures

Han

Fujita

Chen

et al. 2020

IUCrJ

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Bicontinuous cubic structures in soft matter consist of two intertwining labyrinths separated by a partitioning layer. Combining experiments, numerical modelling and techniques in differential geometry, we investigate twinning defects in bicontinuous cubic structures. We first demonstrate that a twin boundary is most likely to occur at a plane that cuts the partitioning layer almost perpendicularly, so that the perturbation caused by twinning remains minimal. This principle can be used as a criterion to identify potential twin boundaries, as demonstrated through detailed investigations of mesoporous silica crystals characterized by diamond and gyroid surfaces. We then discuss that a twin boundary can result from a stacking fault in the arrangement of inter-lamellar attachments at an early stage of structure formation. It is further shown that enhanced curvature fluctuations near the twin boundary would cost energy because of geometrical frustration, which would be eased by a crystal distortion that is experimentally observed.

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Section: Numerical Modelling Of Minimal and Cmc Twinssupporting

confidence: 79%

Section: Numerical Modelling Of Minimal and Cmc Twinssupporting

confidence: 76%

Crystal twinning of bicontinuous cubic structures

Han

Fujita

Chen

et al. 2020

IUCrJ

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“…Here, we develop and use a technique based on surface reconstruction (SI Text), which closely follows the one successfully applied to study amphiphilic systems (43). More specifically, we construct a surface enveloping the arms of the gel.…”

Section: Resultsmentioning

confidence: 99%

Arrested demixing opens route to bigels

Varrato

Michele

Belushkin

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

107

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Understanding and, ultimately, controlling the properties of amorphous materials is one of the key goals of material science. Among the different amorphous structures, a very important role is played by colloidal gels. It has been only recently understood that colloidal gels are the result of the interplay between phase separation and arrest. When short-ranged attractive colloids are quenched into the phase-separating region, density fluctuations are arrested and this results in ramified amorphous space-spanning structures that are capable of sustaining mechanical stress. We present a mechanism of aggregation through arrested demixing in binary colloidal mixtures, which leads to the formation of a yet unexplored class of materials--bigels. This material is obtained by tuning interspecies interactions. Using a computer model, we investigate the phase behavior and the structural properties of these bigels. We show the topological similarities and the geometrical differences between these binary, interpenetrating, arrested structures and their well-known monodisperse counterparts, colloidal gels. Our findings are supported by confocal microscopy experiments performed on mixtures of DNA-coated colloids. The mechanism of bigel formation is a generalization of arrested phase separation and is therefore universal.spinodal decomposition | DNA-coated colloids | programmable interactions | amorphous self-assembly T he properties of a self-assembled material are ultimately controlled by the interactions among its building blocks and by the conditions in which they are prepared. It is by tuning these two properties that different structures can be obtained. Shortranged attractive colloidal systems, for example, can form crystals, two glasses of different origin, or gels. The latter have great technological importance. Colloidal gels find applications in synthetic colloid porous materials (1, 2), functionalization of surfaces and films production (3, 4), ceramics processing (5, 6), protein assemblies (7, 8), food science (9, 10), and soft matter (11, 12). Although they have been known for some time (13,14), it has only recently been understood that the colloidal gels arise as a result of arrested phase separation (15-18).The gels are characterized by a ramified amorphous spacespanning structure that is capable of sustaining mechanical stress. The colloidal density plays a crucial role in the aggregation and therefore in the resulting structure. At low densities, irreversible aggregation leads to fractal gels. At intermediate densities more compact porous structures are observed, whereas a homogeneous glass emerges when the solute occupies more than 50% of the volume (11,10,14,19).It has been proven that when colloidal particles are quenched into the gas-liquid phase separation region, gelation occurs as a consequence of dynamic arrest that interferes with phase separation (15, 18). After the quench, the system is thermodynamically unstable and strong density fluctuations set in, favoring the separation of the fluid into two ...

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“…This was similar to surfactant systems in bulk, in which Belushkin et. al [33] found with a Ginzburg-Landau model that the grain boundary between two orthogonal lamellar grains was a good approximation of a minimal surface and was well described by the Scherk's first surface. Thus, our simulations showed that the formation of the interface between domains resulted in a bicontinuous and double-periodic structure.…”

Section: Figmentioning

confidence: 97%

Morphology of Lamellae-Forming Block Copolymer Films between Two Orthogonal Chemically Nanopatterned Striped Surfaces

et al. 2012

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The structure of block copolymers results from the interplay between weak intermolecular forces, typically in the order of k(B)T per molecule. This is particularly true for block copolymer thin films in the presence of chemically patterned surfaces, where the different contributions to the total free energy, the interfacial and bulklike terms, have comparable magnitudes. Here, we report on the structures formed by block copolymers films equilibrated between two chemically patterned surfaces with orthogonal stripes. Our experiments and simulations reveal that the domains are continuous through the film and the interface between domains resembles the Scherk's first minimal surface. The impact of chemical patterns on block copolymer morphologies and the underlying physics gives insight into the nanofabrication of complex nanostructures with directed self-assembly using two engineered boundary conditions, as opposed to only one.

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Twist grain boundaries in cubic surfactant phases

Cited by 9 publications

References 43 publications

Crystal twinning of bicontinuous cubic structures

Crystal twinning of bicontinuous cubic structures

Arrested demixing opens route to bigels

Morphology of Lamellae-Forming Block Copolymer Films between Two Orthogonal Chemically Nanopatterned Striped Surfaces

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