Decoration of Microparticles by Highly Charged Nanoparticles

Huang, Haohao; Ruckenstein, Eli

doi:10.1021/jp401889m

Cited by 10 publications

(7 citation statements)

References 17 publications

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“…This implies that the interaction between GO and GnP is the highest at this combination which also suggests that much of the hydrophilic sites on GO are occupied by GnP. Previous studies have also highlighted an optimum concentration range of colloidal mixtures to yield a stable hybrid system [ 84 , 115 , 116 ]. As the GnP concentration increases beyond this benchmark, the viscosity rapidly drops which may indicate the saturation of GnP on GO sheet and the remaining particles will strongly flocculate and form much bigger structures.…”

Section: Resultsmentioning

confidence: 83%

Investigation on the use of graphene oxide as novel surfactant to stabilize weakly charged graphene nanoplatelets

et al. 2015

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This paper presents a unique synergistic behavior between a graphene oxide (GO) and graphene nanoplatelet (GnP) composite in an aqueous medium. The results showed that GO stabilized GnP colloid near its isoelectric point and prevented rapid agglomeration and sedimentation. It was considered that a rarely encountered charge-dependent electrostatic interaction between the highly charged GO and weakly charged GnP particles kept GnP suspended at its rapid coagulation and phase separation pH. Sedimentation and transmission electron microscope (TEM) micrograph images revealed the evidence of highly stable colloidal mixtures while zeta potential measurement provided semi-quantitative explanation on the mechanism of stabilization. GnP suspension was confirmed via UV-vis spectral data while contact angle measurement elucidated the close resemblance to an aqueous solution indicating the ability of GO to mediate the flocculation prone GnP colloids. About a tenfold increase in viscosity was recorded at a low shear rate in comparison to an individual GO solution due to a strong interaction manifested between participating colloids. An optimum level of mixing ratio between the two constituents was also obtained. These new findings related to an interaction between charge-based graphitic carbon materials would open new avenues for further exploration on the enhancement of both GO and GnP functionalities particularly in mechanical and electrical domains.

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Section: Resultsmentioning

confidence: 83%

Investigation on the use of graphene oxide as novel surfactant to stabilize weakly charged graphene nanoplatelets

et al. 2015

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“…Mixtures of charged colloids have been modeled, e.g., by integral-equation theory [64][65][66][67][68][69][70][71][72][73], Poisson-Boltzmann theory [74][75][76][77][78], and computer simulation [79][80][81][82][83]. Motivated by experimental observations, several studies of colloid-nanoparticle mixtures [69,71,77,78,80] computed effective pair interactions between colloids that are qualitatively consistent with the postulated nanoparticle haloing mechanism. Further studies are needed, however, to chart the multidimensional parameter space.…”

Section: Introductionmentioning

confidence: 99%

Effective electrostatic interactions in colloid-nanoparticle mixtures

Denton

2017

Phys. Rev. E

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Interparticle interactions and bulk properties of colloidal suspensions can be substantially modified by addition of nanoparticles. Extreme asymmetries in size and charge between colloidal particles and nanoparticles present severe computational challenges to molecular-scale modeling of such complex systems. We present a statistical mechanical theory of effective electrostatic interactions that can greatly ease large-scale modeling of charged colloid-nanoparticle mixtures. By applying a sequential coarse-graining procedure, we show that a multicomponent mixture of charged colloids, nanoparticles, counterions, and coions can be mapped first onto a binary mixture of colloids and nanoparticles and then onto a one-component model of colloids alone. In a linear-response approximation, the one-component model is governed by a single effective pair potential and a one-body volume energy, whose parameters depend nontrivially on nanoparticle size, charge, and concentration. To test the theory, we perform molecular dynamics simulations of the two-component and one-component models and compute structural properties. For moderate electrostatic couplings, colloid-colloid radial distribution functions and static structure factors agree closely between the two models, validating the sequential coarse-graining approach. Nanoparticles of sufficient charge and concentration enhance screening of electrostatic interactions, weakening correlations between charged colloids and destabilizing suspensions, consistent with experiments.

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“…where the Hamaker constant A ij depends on the dielectric constants of both the particles and the medium. Since we restrict attention here to like-charged particles whose repulsive electrostatic interactions are sufficiently strong to prevent nanoparticle adsorption, we neglect dielectric polarization effects, as in previous studies of charged colloidal mixtures [23][24][25][26][27][28][29][30][31][32][33][34][35][37][38][39][40][41]. Although induced polarization charges may affect self-assembly of strongly coupled, oppositely charged colloidal mixtures [42], charge-charge interactions are expected to dominate in the moderately coupled, like-charged systems investigated here.…”

Section: Coarse-grained Model Of Colloid-nanoparticle Mixturesmentioning

confidence: 99%

“…Charged colloidal mixtures have been modeled by a variety of theoretical and computational methods, including computer simulations [22][23][24][25][26], integral-equation theory [27][28][29][30][31][32][33][34][35][36], and Poisson-Boltzmann theory [37][38][39][40][41]. Several recent studies of highly asymmetric mixtures of charged colloids and nanoparticles [23,32,33,40,41] yielded effective colloid-colloid pair interactions that support the postulated nanoparticle haloing mechanism for certain system parameters. However, while previous studies have focused on weakly charged colloids mixed with oppositely-charged nanoparticles, relatively little is known about the influence on suspensions of strongly charged colloids of like-charged nanoparticles.…”

Section: Introductionmentioning

confidence: 99%

Structure and stability of charged colloid-nanoparticle mixtures

Weight

Denton

2018

The Journal of Chemical Physics

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Physical properties of colloidal materials can be modified by addition of nanoparticles. Within a model of like-charged mixtures of particles governed by effective electrostatic interactions, we explore the influence of charged nanoparticles on the structure and thermodynamic phase stability of charge-stabilized colloidal suspensions. Focusing on salt-free mixtures of particles of high size and charge asymmetry, interacting via repulsive Yukawa effective pair potentials, we perform molecular dynamics simulations and compute radial distribution functions and static structure factors. Analysis of these structural properties indicates that increasing the charge and concentration of nanoparticles progressively weakens correlations between charged colloids. We show that addition of charged nanoparticles to a suspension of like-charged colloids can induce a colloidal crystal to melt and can facilitate aggregation of a fluid suspension due to attractive van der Waals interactions. We attribute the destabilizing influence of charged nanoparticles to enhanced screening of electrostatic interactions, which weakens repulsion between charged colloids. This interpretation is consistent with recent predictions of an effective interaction theory of charged colloid-nanoparticle mixtures.

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Decoration of Microparticles by Highly Charged Nanoparticles

Cited by 10 publications

References 17 publications

Investigation on the use of graphene oxide as novel surfactant to stabilize weakly charged graphene nanoplatelets

Investigation on the use of graphene oxide as novel surfactant to stabilize weakly charged graphene nanoplatelets

Effective electrostatic interactions in colloid-nanoparticle mixtures

Structure and stability of charged colloid-nanoparticle mixtures

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