Controlled and rapid ordering of oppositely charged colloidal particles

Sharma, Vyom; Yan, Qingfeng; Wong, Chee Cheong; Carter, W. Craig; Chiang, Yet‐Ming

doi:10.1016/j.jcis.2009.01.047

Cited by 22 publications

(19 citation statements)

References 36 publications

(44 reference statements)

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“…where 5 is the separation distance between particles in solution and A is the Hamaker constant for polystyrene spheres separated by water and is equal to 0.95 x 10^ [32,33]. Coulomb's law gives the electrostatic force between two charges as [34] ( 6) where SQ is the vacuum permittivity, q is the charge, and h is the separation distance.…”

Section: Discussionmentioning

confidence: 99%

Size-Dependent Nanoparticle Margination and Adhesion Propensity in a Microchannel

Agarwal

Singh

Roy

et al. 2013

Journal of Nanotechnology in Engineering and Medicine

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Intravenous injection of nanoparticies as drug delivery vehicles is a common practice in clinical trials of therapeutic agents to target specific cancerous or pathogenic sites. The vascular flow dynamics of nanocarriers (NCs) in human microcapillaries play an important role in the ultimate efficacy of this drug delivery method. This article reports an experimental study of the effect of nanoparticle size on their margination and adhesion propensity in microfluidic channels of a half-elliptical cross section. Spherical polystyrene particles ranging in diameter from 60 to 970 nm were flown in the microchannels and individual particles adhered to either the top or bottom wall of the channel were imaged using fluorescence microscopy. When the number concentration of particles in the flow was kept constant, the percentage of nanoparticies adhered to the top wall increased with decreasing diameter (d), with the number of particles adhered to the top wail following a d^^ trend. When the volume concentration of particles in solution was kept constant, no discernible trend was found. This experimental finding is explained by the competition between the Brownian force promoting margination and repulsive particle-particle electrostatic forces retarding adhesion to the wall. The 970 nm particles were found to adhere to the bottom wall much moré than to the top wall for each of the three physiologically relevant shear rates tested, revealing the effect of gravitational force on the large particles. These findings on the flow behavior of spherical nanoparticies in artificial microcapillaries provide further insight for the rational design of NCs for targeted cancer therapeutics. [DOL iO.l 115/1.4025609]

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Section: Discussionmentioning

confidence: 99%

Size-Dependent Nanoparticle Margination and Adhesion Propensity in a Microchannel

Agarwal

Singh

Roy

et al. 2013

Journal of Nanotechnology in Engineering and Medicine

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“…However, close-packed lattices have limited available symmetries (FCC or HCP) and associated properties which are too restrictive for diverse potential applications, especially in photonics. Using a mixed suspension of two particle types, colloidal crystals with lower symmetries can be made possible to provide novel properties in photonics, sensing and filtering (Bartlett et al, 1992;Kitaev & Ozin, 2003;Sharma et al, 2009;Tan et al, 2008). Layer-by-layer growth is commonly used to self-assemble these structures, with right conditions of surfactants, temperature and ionic strength.…”

Section: Mobility In Binary Colloidmentioning

confidence: 99%

“…12a), each interstice in the first layer of hexagonally close packed (hcp) particles (L) is filled by one small particle (S). LS 6 structure is also possible where each interstice of first layer is filled by three particles (S) instead (Sharma et al, 2009). Unfortunately, both lower and higher densities of binary structures are usually observed together in LBL experiments.…”

Section: Mobility In Binary Colloidmentioning

confidence: 99%

Colloidal Crystals

Ng¹,

K.²,

Chi³

2012

Modern Aspects of Bulk Crystal and Thin Film Preparation

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“…The diamond cubic structure is an exemplar of particular interest due to its complete photonic band gap. 1,2 Researchers have also used spontaneous self-assembly of particles (through spin-coating, 3,4 convective assembly, 5,6 etc.) to create dense-packed binary colloidal crystals.…”

Section: Introductionmentioning

confidence: 99%

Templated self-assembly of non-close-packed colloidal crystals: Toward diamond cubic and novel heterostructures

et al. 2011

Self Cite

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We demonstrate the formation of non-close-packed binary colloidal structures through a novel layer-by-layer directed self-assembly methodology. In this approach we deposit colloidal suspensions of particle concentration and controlled electrostatic potential onto a planar template with a periodic array of features that is able to trap the particles, nucleating ordered domains with a template-defined symmetry and periodicity that permits subsequent, sequential deposition to produce an ordered heterostructure. Specifically, a silicon template with a hole pattern formed by interference lithography that corresponds to [100] symmetry of a cubic system has been used. At low particle concentrations, and using a Debye length that is on the order of the particle diameter, ordered domains in which polystyrene (PS) particles occupy every other site in the template are formed. The remaining sites on the 2D template are then filled by identically sized silica particles using vertical deposition. This process is repeated to produce a second layer of the same structure. Upon removing the PS particles, a two-layer non-close-packed structure that is a half-unit-cell precursor to the diamond cubic structure is obtained. To our knowledge this is the first demonstration of colloidal self-assembly to obtain a non-close-packed multilayer structure. Challenges that remain in applying the approach to create extended three-dimensional structures are discussed.

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Controlled and rapid ordering of oppositely charged colloidal particles

Cited by 22 publications

References 36 publications

Size-Dependent Nanoparticle Margination and Adhesion Propensity in a Microchannel

Size-Dependent Nanoparticle Margination and Adhesion Propensity in a Microchannel

Colloidal Crystals

Templated self-assembly of non-close-packed colloidal crystals: Toward diamond cubic and novel heterostructures

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