Charging Mechanism for Polymer Particles in Nonpolar Surfactant Solutions: Influence of Polymer Type and Surface Functionality

Lee, Joohyung; Zhou, Zhang‐Lin; Behrens, Sven H.

doi:10.1021/acs.langmuir.6b00583

Cited by 22 publications

(45 citation statements)

References 63 publications

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“…Nanoparticle NP1 and NP2 were, in contrast, charged negative by addition of the oil-soluble ionic surfactant Aerosol-OT at molar concentrations C AOT above the critical micellar concentration so that spherical reverse micelles form in solution. It has been proposed 14,36 that charge regulation in systems containing AOT is a multi-site CR 2 process with two independent association reactions,…”

Section: B Charge Regulationmentioning

confidence: 99%

Charge regulation of nonpolar colloids

et al. 2018

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Individual colloids often carry a charge as a result of the dissociation (or adsorption) of weakly-ionized surface groups. The magnitude depends on the precise chemical environment surrounding a particle, which in a concentrated dispersion is a function of the colloid packing fraction η. Theoretical studies have suggested that the effective charge Z eff in regulated systems could, in general, decrease with increasing η. We test this hypothesis for nonpolar dispersions by determining Z eff (η) over a wide range of packing fractions (10 −5 ≤ η ≤ 0.3) using a combination of small-angle X-ray scattering and electrophoretic mobility measurements. All dispersions remain entirely in the fluid phase regime. We find a complex dependence of the particle charge as a function of the packing fraction, with Z eff initially decreasing at low concentrations before finally increasing at high η. We attribute the non-monotonic density dependence to a crossover from concentrationindependent screening at low η, to a high packing fraction regime in which counterions outnumber salt ions and electrostatic screening becomes η-dependent. The efficiency of charge stabilization at high concentrations may explain the unusually high stability of concentrated nanoparticle dispersions which has been reported 1 .

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Section: B Charge Regulationmentioning

confidence: 99%

Charge regulation of nonpolar colloids

et al. 2018

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“…However, some oil-soluble surfactants have been reported to promote electric charging in nonpolar media and colloidal surfaces suspended therein. , [24,[31][32][33][34][35][36][37][38][39][40][41][42][43][44] In nonpolar media, the dissolved surfactants can self-assemble and form inverse micelles that have polar pools at the core. It is widely believed that electric charges can be stabilized in these local high-dielectric environments with a reduced energetic cost of charging (born energy of the ion) and the inverse micelles-as charge carriers-could increase the electrical conductivity of nonpolar media.…”

Section: Introductionmentioning

confidence: 99%

“…It is widely believed that electric charges can be stabilized in these local high-dielectric environments with a reduced energetic cost of charging (born energy of the ion) and the inverse micelles-as charge carriers-could increase the electrical conductivity of nonpolar media. [45][46][47][48] Several hypotheses have been proposed for the surface charging mechanisms of suspended colloidal particles: 1) surfactants adsorb on the particle surface, donate or accept charges depending on the relative acid-base strengths between the surfactants and surfaces, and the charged surfactants desorb, leaving charges with opposite signs on the particle surface (this mechanism is often referred to as the acid-base particle charging mechanism); [24,34,38] 2) particles are charged via the asymmetric or preferential adsorption of charged entities from the nonpolar solution phase onto the particle surface; [32,[35][36][37]39,40] 3) particles are charged via the dissociation of some surface functional groups, [40,43] with the dissociated ions stabilized in the inverse micelles in the nonpolar solution phase. However, the exact mechanisms are still under debate and a matter of ongoing research.…”

Section: Introductionmentioning

confidence: 99%

Electrostatic Stabilization of Nano Liquid Metals in Doped Nonpolar Liquids

Kim

Jeong

Hyun

et al. 2021

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their range of applications could be substantially extended beyond the traditional ones based on liquid metals as a continuous fluid. To date, liquid-metal particles of micro-or nano-sizes have demonstrated promising performances in diverse research areas such as self-healing electronics, [8,9] thermal interface materials, [10,11] catalytic reaction implementation, [12] drug delivery, [13] and plasmonics. [14] Among the various methods developed for manufacturing liquid-metal particles, [15,16] sonication is most commonly employed, [5][6][7] which breaks the bulk liquid metal into small entities in a desired solvent. The dispersed liquid-metal particles have a thin oxide skin that forms spontaneously on a surface, [1] which prevents liquidmetal droplet coalescence and allows them to maintain their particulate form. The modulation of the surface oxide, typically with the support of surface-bound ligands, [17,18] can be used to precisely control the mechanical, electrical, and optical properties of liquid-metal particles that carry the liquid-state core under the outermost oxide surface. This can provide unique opportunities that are inaccessible by conventional all-solid-state metal and metal oxide particles.Despite the large number of studies on the preparation and applications of micro-and nano-sized liquid-metal particles reported to date, less attention has been focused on the colloidal behavior of such particles suspended in liquid media. To the best of our knowledge, no studies have been conducted on liquid-metal colloids in highly nonpolar organic solvents such as saturated hydrocarbons. Nonpolar colloidal dispersions are crucial in various industrial applications, the best-known example of which is the electronic ink embedded in an electrophoretic display. [19][20][21][22] Owing to the low electrical conductivity of nonpolar solvents, the power consumption of electrophoretic displays is low, which can be beneficial in the development of emerging portable and wearable Internet-of-Things (IoT) devices. Thus, classical electronic ink technology was recently combined with a triboelectric nanogenerator (TENG) to develop self-powered and low-power-consumption electronic paper. [23] Other useful applications of nonpolar dispersions include oilbased printing toners for electrostatic lithographic printers, [24] electrorheological fluids, [25,26] photonic crystals, [27] and drug delivery systems. [28] While conventional nonpolar dispersions used in such applications employ all-solid-state particles, new Liquid metals and alloys are attracting renewed attention owing to their potential for application in various advanced technologies. Eutectic galliumindium (EGaIn) has been focused on in particular because of its integrated advantages of high conductivity, low melting point, and low toxicity. In this study, the colloidal behavior of nano-dispersed EGaIn in nonpolar oils is investigated. Although the nonpolar oil continuous phase is commonly considered to be free of electric charges, electrostatic repulsion appears to...

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“…Processes occurring at solid-liquid interfaces are of critical importance for a variety of applications spanning diverse fields including geochemistry, environmental science, catalysis, solar energy, corrosion protection, and many others [1]. Examples of such processes include interactions involving (dis)charging of colloids [2][3][4][5][6][7][8], physisorption and chemisorption [9][10][11][12], (electro)chemical reactions, and photocharging [13], all of which involve evolution of the effective surface charge. In order to understand these processes, it is important to develop tools that enable systematic studies of these interactions, depending on the nature of the interface.…”

Section: Introductionmentioning

confidence: 99%

Simultaneous fluorescence and surface charge measurements on organic semiconductor-coated silica microspheres in (non)polar liquids

et al. 2017

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We present an experimental platform which combines spectroscopic capabilities with time-resolved measurements of effective surface charge at solid-liquid interfaces. Silica microspheres, pristine and coated with various organic semiconductor molecules, were optically trapped either in water or in toluene. Adsorption of organic semiconductor molecules on the microspheres was observed via appearance of fluorescence and dramatic reduction in the effective surface charge, measured concurrently on individual spheres, with elementary charge resolution. The versatile platform accommodates possibilities to study a variety of photoinduced processes simultaneously with measurements of surface charge and can be incorporated in devices such as microreactors and microfluidics.

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Charging Mechanism for Polymer Particles in Nonpolar Surfactant Solutions: Influence of Polymer Type and Surface Functionality

Cited by 22 publications

References 63 publications

Charge regulation of nonpolar colloids

Charge regulation of nonpolar colloids

Electrostatic Stabilization of Nano Liquid Metals in Doped Nonpolar Liquids

Simultaneous fluorescence and surface charge measurements on organic semiconductor-coated silica microspheres in (non)polar liquids

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