Colloidal chemistry

homogeneous mixture composed of only one phase

thumb|upright=1.4|Mist and [[fog are aerosols|alt=photograph of heavy mist]]

the random motion of particles suspended in a fluid resulting from their collision with the quick atoms or molecules in the gas or liquid

A colloid is a mixture in which one substance, consisting of microscopically dispersed insoluble particles, is suspended throughout another substance. Some definitions specify that the particles must be dispersed in a liquid, while others extend the definition to include substances like aerosols and gels. The term colloidal suspension refers unambiguously to the overall mixture (although a narrower sense of the word suspension is distinguished from colloids by larger particle size). A colloid has a dispersed phase (the suspended particles) and a continuous phase (the medium of suspension). thu

thumb|Brunauer, Emmett, and Teller's #BET|model of multilayer adsorption is a random distribution of molecules on the material surface.

heterogeneous mixture

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thumb|Schematic diagram of a [[micelle of oil in aqueous suspension, such as might occur in an emulsion of oil in water. In this example, the surfactant molecules' oil-soluble tails project into the oil (blue), while the water-soluble ends remain in contact with the water phase (red).]]

thumb|300px|1. Illustration of electrophoresis thumb|300px|2. Illustration of electrophoresis retardation

thumb|250px|right|Cross-section view of the structures that can be formed by phospholipids in aqueous solutions (unlike this illustration, micelles are usually formed by single-chain lipids, since it is difficult to fit two chains into this shape) thumb|250px|right|Scheme of a micelle formed by phospholipids in an [[aqueous solution]]

mixture in which components are dispersed in a continuous phase of different composition, where at least one of the phases consists of finely divided phase domains

ratio of permittivity to the electric constant

thumb|Turbidity standards of 5, 50, and 500 NTU

quantification of the electrical interactions between ions in solution

branch of chemistry and physics

layer enriched with ions of opposite charge to that carried by a solid surface to maintain electroneutrality in solution

colloidal suspension of very small solid particles in a continuous liquid medium

measure of a charge carrier's net electrostatic effect in a solution and how far it persists

thumb|Coacervate droplets dispersed in a dilute phaseCoacervate ( or ) is an aqueous phase rich in macromolecules such as synthetic polymers, proteins or nucleic acids. It forms through liquid-liquid phase separation (LLPS), leading to a dense phase in thermodynamic equilibrium with a dilute phase. The dispersed droplets of dense phase are also called coacervates, micro-coacervates or coacervate droplets. These structures draw a lot of interest because they form spontaneously from aqueous mixtures and provide stable compartmentalization without the need of a membrane—they are protocell candida

Behaviour of charged particles near a semi-permeable membrane

thumb|right|Gelatin, here in sheets for cooking, is a hydrogel. thumb|Peptide hydrogel formation shown by the inverted vial method.

electrokinetic potential in colloidal dispersions

cloudy emulsion resulting from adding water to ouzo

the concentration of surfactants above which micelles are spontaneously formed

thumb|200px|Chemical structures of two synthetic polyelectrolytes, as examples. To the left is sodium polystyrene sulfonate|poly(sodium styrene sulfonate) (PSS), and to the right is [[polyacrylic acid (PAA). Both are negatively charged polyelectrolytes when dissociated. PSS is a 'strong' polyelectrolyte (fully charged in solution), whereas PAA is 'weak' (partially charged).]]

Imbibition is a special type of diffusion that takes place when liquid is absorbed by solids-colloids causing an increase in volume. Water surface potential movement takes place along a concentration gradient; some dry materials absorb water. A gradient between the absorbent and the liquid is essential for imbibition. For a substance to imbibe a liquid, there must first be some attraction between them. Imbibition occurs when a wetting fluid displaces a non-wetting fluid, the opposite of drainage in which a non-wetting phase displaces the wetting fluid. The two processes are governed by differe

boundary between different phases of matter

thumb|right|250px|Dosage of defoamer A defoamer or an anti-foaming agent is a chemical additive that reduces and hinders the formation of foam in industrial process liquids. The terms anti-foam agent and defoamer are often used interchangeably. Strictly speaking, defoamers eliminate existing foam and anti-foamers prevent the formation of further foam. Commonly used agents are insoluble oils, polydimethylsiloxanes and other silicones, certain alcohols, stearates and glycols. The additive is used to prevent formation of foam or is added to break a foam already formed.

function representing relative sizes of particles in a system

thumb|210px|right|A nephelometer at the Kosan, Cheju Island, South Korea NOAA facility

process in which small crystals preferentially dissolve and re-precipitate onto larger crystals over time

thumb|320px|alt="dielectrophoresis of cancer cells"|Dielectrophoresis assembling cancer cells in a 3D microfluidic model.

thumb|A uniform (monodisperse) collectionthumb|A non-uniform (polydisperse) collection

thumb|right|300px|Polysorbate 20, a compound used as a food additive in some pudding mixes to prevent scorching during preparation Polysorbates are a class of emulsifiers used in some pharmaceuticals and food preparation. They are commonly used in oral and topical pharmaceutical dosage forms. They are also often used in cosmetics to solubilize essential oils into water-based products. Polysorbates are oily liquids derived from ethoxylated sorbitan (a derivative of sorbitol) esterified with fatty acids. Common brand names for polysorbates include Hedjuvan, Kolliphor, Scattics, Alkest, Canarcel,

technique for determining size distribution of particles

type of glaciomarine clay

A dispersant or a dispersing agent is a substance, typically a surfactant, that is added to a suspension of solid or liquid particles in a liquid (such as a colloid or emulsion) to improve the separation of the particles and to prevent their settling or clumping.

equation describing the distribution of the electric potential in solution in the direction normal to a charged surface

theoretical model for aggregation of aqueous dispersions

Surfactin is a cyclic lipopeptide, commonly used as an antibiotic for its capacity as a surfactant. It is an amphiphile capable of withstanding hydrophilic and hydrophobic environments. The Gram-positive bacterial species Bacillus subtilis produces surfactin for its antibiotic effects against competitors. Surfactin showcases antibacterial, antiviral, antifungal, and hemolytic effects.

extraction or expulsion of a liquid from a gel

family of several different effects that occur in heterogeneous fluids, or in porous bodies filled with fluid, or in a fast flow over a flat surface

thumb|Settling pond for iron particles at water works

direct mutual attraction between particles (atoms or molecules) via van der Waals forces or chemical bonding

The peptization of a liquid mixture is the process of converting the mixture into a colloid by shaking it with a suitable electrolyte called a peptizing agent. That is, the insoluble solid particles which have settled out of the mixture (i.e. the precipitate) are reformed into microscopic particles suspended in the mixture. Peptization is the reverse of flocculation, the aggregation of colloidal particles into precipitate; as such, it is also known as deflocculation.

material property relevant for characterizing fluid flow

minimum temperature at which surfactants form micelles

Superplasticizers (SPs), also known as high-range water reducers (HRWRs), are additives used for making high-strength concrete or to place self-compacting concrete. Plasticizers are chemical compounds enabling the production of concrete with approximately 15% less water content. Superplasticizers allow reduction in water content by 30% or more. These additives are employed at the level of a few weight percent. Plasticizers and superplasticizers also retard the setting and hardening of concrete.

Distance at which electrostatic interaction between two electrical charges is comparable to their thermal energy

Microemulsions are clear, thermodynamically stable, isotropic liquid mixtures of oil, water and surfactant, frequently in combination with a cosurfactant. The aqueous phase may contain salt(s) and/or other ingredients, and the "oil" may actually be a complex mixture of different hydrocarbons. In contrast to ordinary emulsions, microemulsions form upon simple mixing of the components and do not require the high shear conditions generally used in the formation of ordinary emulsions. The three basic types of microemulsions are direct (oil dispersed in water, o/w), reversed (water dispersed in oil

effect

type of solution

REDIRECT Colloid#Hydrocolloids Category:Colloidal chemistry

occurs when dispersed particles move under the influence of either gravity or centrifugation in a medium

process of incorporating the solubilizate into or onto micelles

dimensionless quantity that characterizes the contribution of the surface conductivity to various electrokinetic and electroacoustic effects, as well as to electrical conductivity and permittivity of fluid heterogeneous systems

The pH value at which the surface of a colloidal solid carries no net electrical charge

formula for sound intensity loss in a Newtonian fluid

an ordered array of colloid particles, analogous to a standard crystal whose repeating subunits are atoms or molecules