Reversible long range network formation in gold nanoparticle - nematic liquid crystal composites

Milette, Jonathan; Cowling, Stephen J.; Toader, Violeta; Lavigne, Cyrille; Sáez, Isabel M.; Lennox, R. Bruce; Goodby, John W.; Reven, Linda

doi:10.1039/c1sm06604h

Cited by 79 publications

(111 citation statements)

References 28 publications

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“…7 For sterically stabilized colloids or nanoparticles, aggregation arises through interaction of particles with the mesogenic solvent. 9 Previous experimental investigations of colloid-LC mixtures [9][10][11][12][13][14][15][16][17] posit different mechanisms and structures for gelation, depending on the nature of dispersion. When colloids are dispersed in an isotropic LC phase, cooling of the liquid below the IN transition temperature favors the nucleation of nematic droplets within the mixed phase.…”

Section: Introductionmentioning

confidence: 99%

Liquid-crystal mediated nanoparticle interactions and gel formation

Whitmer

Joshi

Roberts

et al. 2013

The Journal of Chemical Physics

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Colloidal particles embedded within nematic liquid crystals exhibit strong anisotropic interactions arising from preferential orientation of nematogens near the particle surface. Such interactions are conducive to forming branched, gel-like aggregates. Anchoring effects also induce interactions between colloids dispersed in the isotropic liquid phase, through the interactions of the pre-nematic wetting layers. Here we utilize computer simulation using coarse-grained mesogens to perform a molecular-level calculation of the potential of mean force between two embedded nanoparticles as a function of anchoring for a set of solvent conditions straddling the isotropic-nematic transition. We observe that strong, nontrivial interactions can be induced between particles dispersed in mesogenic solvent, and explore how such interactions might be utilized to induce a gel state in the isotropic and nematic phases.

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Section: Introductionmentioning

confidence: 99%

Liquid-crystal mediated nanoparticle interactions and gel formation

Whitmer

Joshi

Roberts

et al. 2013

The Journal of Chemical Physics

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“…Secondly, the diffraction efficiency decreases for longer wavelengths as expected from the inverse proportionality of Eq. (14). Finally, Table I. the diffraction is fairly insensitive to the aspect ratio of the particles.…”

Section: A Optimization Of the Gold Nanoparticle Liquid Crystal Compmentioning

confidence: 99%

“…Moreover, even low concentration suspensions have increased the nonlinearity of hybrid photorefractive liquid crystal cells [13]. Liquid crystals have also been shown to cause gold nanoparticles to spontaneously form linear self-assemblies [14] and large 3D plasmonic crystals have been formed in an LC host using optical tweezers [15]. Gold nanoparticles functionalized with liquid crystalline surfactants have been demonstrated to form large, complex, self-assembled structures, which exhibit anisotropic absorption [16,17].…”

Section: Introductionmentioning

confidence: 99%

Gold nanoparticle liquid crystal composites as a tunable nonlinear medium

2014

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We investigate the nonlinearity of a liquid crystal cell doped with gold nanoparticles by considering their selective absorption. Such nonlinearities are promising for optical processing applications and optical limiters. Systems displaying thermal nonlinearities are particularly attractive as the maximum nonlinearity may occur in the absence of an applied field and additionally this nonlinearity can be controlled by the reorientation of the liquid crystal. We show that there exists a theoretical optimum concentration of absorbers, which maximizes the nonlinearity. Further we show that the nonlinearity of the system can be tuned by the reorientation of the liquid crystal host, with the nonlinearity decreasing from 9×10 −5 cm 2 W −1 to zero by the application of a magnetic field of the order of 0.01 Tesla. This allows a fine control of the diffraction efficiency and, in principle, many other nonlinear effects.

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“…Elasticity-mediated interactions between particles cause micron-sized particles to self-organize into chains or clusters that are strongly (∼1000k B T ) bound together [2,[5][6][7]. Smaller nanoparticles (NPs) disperse uniformly in the isotropic phase but can be sculpted into a variety of structures by kinetic effects as the host undergoes a transition into a liquid crystalline phase [1,8,9]. Self-assembly of nanoparticles in LCs can therefore exploit nucleation and growth as would occur in an isotropic fluid [10,11], but the liquid crystalline order permits additional control over the self-assembled structure [9].…”

Section: Introductionmentioning

confidence: 99%

Modeling deformation and chaining of flexible shells in a nematic solvent with finite elements on an adaptive moving mesh

DeBenedictis¹,

Atherton²,

Rodarte³

et al. 2018

Phys. Rev. E

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A micrometer-scale elastic shell immersed in a nematic liquid crystal may be deformed by the host if the cost of deformation is comparable to the cost of elastic deformation of the nematic. Moreover, such inclusions interact and form chains due to quadrupolar distortions induced in the host. A continuum theory model using finite elements is developed for this system, using mesh regularization and dynamic refinement to ensure quality of the numerical representation even for large deformations. From this model, we determine the influence of the shell elasticity, nematic elasticity, and anchoring condition on the shape of the shell and hence extract parameter values from an experimental realization. Extending the model to multibody interactions, we predict the alignment angle of the chain with respect to the host nematic as a function of aspect ratio, which is found to be in excellent agreement with experiments.

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Reversible long range network formation in gold nanoparticle - nematic liquid crystal composites

Cited by 79 publications

References 28 publications

Liquid-crystal mediated nanoparticle interactions and gel formation

Liquid-crystal mediated nanoparticle interactions and gel formation

Gold nanoparticle liquid crystal composites as a tunable nonlinear medium

Modeling deformation and chaining of flexible shells in a nematic solvent with finite elements on an adaptive moving mesh

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