Fabrication of Colloidal Doublets by a Salting Out−Quenching−Fusing Technique

Yake, Allison M.; Panella, Rocco A.; Snyder, Charles E.; Velegol, Darrell

doi:10.1021/la061339n

Cited by 49 publications

(61 citation statements)

References 58 publications

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“…In these cases the high melting point of the metals does not allow to enhance the stability by fusing but the high Hamaker constants make the attractive van der Waals forces maintain the stability of the dimers. SiO 2 ‐polymer heterodimers can be synthesized by this method,107 as well as by one‐step reaction through a miniemulsion polymerization technique 108. The organic and inorganic reagents were confined in miniemulsion microreactor droplets.…”

Section: Building Blocksmentioning

confidence: 99%

Self‐Assembled Photonic Structures

et al. 2010

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Photonic crystals have proven their potential and are nowadays a familiar concept. They have been approached from many scientific and technological flanks. Among the many techniques devised to implement this technology self-assembly has always been one of great popularity surely due to its ease of access and the richness of results offered. Self-assembly is also probably the approach entailing more materials aspects owing to the fact that they lend themselves to be fabricated by a great many, very different methods on a vast variety of materials and to multiple purposes. To these well-known material systems a new sibling has been born (photonic glass) expanding the paradigm of optical materials inspired by solid state physics crystal concept. It is expected that they may become an important player in the near future not only because they complement the properties of photonic crystals but because they entice the researchers' curiosity. In this review a panorama is presented of the state of the art in this field with the view to serve a broad community concerned with materials aspects of photonic structures and more so those interested in self-assembly.

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Section: Building Blocksmentioning

confidence: 99%

Self‐Assembled Photonic Structures

et al. 2010

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“…Dimers are one of the few nonspherical shapes for which analytical solutions exist; none exist for trimers. We make dimer and triangular trimer clusters through limited aggregation of sulfate polystyrene spheres (Invitrogen) [25], 1.3-µm diameter for dimers and 1-µm diameter for trimers. We transfer these particles into a 250 mM NaCl solution to screen the charge of the stabilizing sulfate groups and start the aggregation, then we decrease the ionic strength by quenching with deionized water (Millipore) after 1 minute to arrest the aggregation.…”

mentioning

confidence: 99%

Holographic measurements of anisotropic three-dimensional diffusion of colloidal clusters

Fung

Manoharan

2013

Phys. Rev. E

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We measure all nonzero elements of the three-dimensional (3D) diffusion tensor D for clusters of colloidal spheres to a precision of 1% or better using digital holographic microscopy. We study both dimers and triangular trimers of spheres, for which no analytical calculations of the diffusion tensor exist. We observe anisotropic rotational and translational diffusion arising from the asymmetries of the clusters. In the case of the three-particle triangular cluster, we also detect a small but statistically significant difference in the rotational diffusion about the two in-plane axes. We attribute this difference to weak breaking of threefold rotational symmetry due to a small amount of particle polydispersity. Our experimental measurements agree well with numerical calculations and show how diffusion constants can be measured under conditions relevant to colloidal self-assembly, where theoretical and even numerical prediction is difficult.Diffusion plays a critical role in the dynamics, selfassembly, and rheology of complex fluids. In systems such as colloidal suspensions, which typically have shortranged interaction potentials, diffusion can in fact play a larger role than energy barriers in setting transition rates [1]. However, the diffusion of geometrically anisotropic particles, a common class of colloidal suspension that can also arise as intermediates in the selfassembly of spherical particles, can be difficult to predict. Theoretically determining friction factors for these particles requires analytically solving Stokes' equation, which is only possible for highly symmetric particles such as ellipsoids [2] or sphere dimers [3] in unbounded fluids. Numerical methods such as bead modeling [4] or finiteelement methods [5][6][7] require approximating the shape of the particles or the hydrodynamic interactions. These methods are difficult to apply when asymmetric particles diffuse near rigid boundaries or other particles, two situations that are relevant to colloidal self-assembly and dynamics in general. Thus experimental measurements of diffusion tensors are crucial.In particular, precision measurements on single particles rather than ensembles are necessary. Anisotropic particles show multiple diffusion timescales that are difficult to resolve through bulk techniques such as depolarized dynamic light scattering [8]. But there have been few single-particle studies of anisotropic diffusion in 3D. Video microscopy has been used to measure twodimensional (2D) diffusion of colloidal ellipsoids [9,10] and planar sphere clusters [11] but the technique yields limited information about out-of-plane motions [12][13][14]. Confocal microscopy can be used to study the 3D dynamics of geometrically anisotropic particles, but has only * vnm@seas.harvard.edu been applied to highly symmetric particles [15,16] and is limited by the time (∼ 1 s) needed to acquire a 3D stack. This can make it challenging to probe timescales comparable to particle diffusion times or to study rare processes such as the early stages of self-assem...

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“…27 This solution is held quiescently for 5 min until the resulting aggregates are repeatedly washed with millipore water and centrifugation to return the aggregates to a low salt concentrations and inhibit further aggregation. The majority of spheres remain isolated and approximately 5 % are clusters of 2 or greater.…”

Section: Methodsmentioning

confidence: 99%

Reversible Adsorption Kinetics of Near Surface Dimer Colloids

Salipante

Hudson

2016

Langmuir

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We investigate the effect of shape on reversible adsorption kinetics using colloidal polystyrene dimers near a solid glass surface as a model system. The interaction between colloid and wall is tuned using electrostatic, depletion, and gravity forces to produce a double well potential. The dwell times in each of the potential wells is measured from long duration particle trajectories. The height of each monomer relative to the glass surface is measured to a resolution of <20 nm by in-line holographic microscopy. The measured transition probability distributions are used in kinetic equations to describe the flux of particles to and from the surface. The dimers are compared to independent isolated monomers to determine the effects of shape on adsorption equilibria and kinetics. To elucidate these differences, we consider both mass and surface coverage and two definitions of surface coverage. The results show that dimers with single coverage produce slower adsorption and lower surface coverage in comparison to monomers while dimers with double coverage adsorb faster and result in higher surface coverage.

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Fabrication of Colloidal Doublets by a Salting Out−Quenching−Fusing Technique

Cited by 49 publications

References 58 publications

Self‐Assembled Photonic Structures

Self‐Assembled Photonic Structures

Holographic measurements of anisotropic three-dimensional diffusion of colloidal clusters

Reversible Adsorption Kinetics of Near Surface Dimer Colloids

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