Emulsions in Chemistry

An emulsion is a mixture of two or more liquids that normally don't mix (immiscible). Imagine oil and water - they separate into distinct layers. Emulsions use a special ingredient (emulsifier) to keep the liquids mixed as tiny droplets.

The type of emulsion depends on which liquid is dispersed and which is the surrounding liquid.

• Oil in Water (O/W): Oil droplets are spread throughout water.
• Water in Oil (W/O): Water droplets are spread throughout oil.

An emulsifying agent is a special ingredient that helps to hold the different liquids together in an emulsion. It acts like a bridge between the liquids, preventing them from separating.

The dispersed liquid is called the Internal Phase (the droplets) and the surrounding liquid is the External Phase.

Emulsions are not perfectly stable and can separate over time. Factors like temperature, the type of emulsifier used, and the size of the droplets all affect how stable an emulsion is.

A type of emulsion where tiny droplets of oil are dispersed throughout a continuous water phase. Examples include milk and some lotions.

A type of emulsion where tiny droplets of water are dispersed throughout a continuous oil phase. Used for topical applications to protect and moisturize skin.

Droplets of oil are dispersed in water (O/W), and then the entire mixture is dispersed in oil (O/W/O). This creates a double emulsion.

Droplets of water are dispersed in oil (W/O), and then the entire mixture is dispersed in water (W/O/W).

Small emulsion droplets (0.01-0.2 mm) that are thermodynamically stable and optically transparent due to their small size.

Emulsions that are unstable over time and require a stabilizing agent to prevent separation.

The process where the oil droplets in an emulsion rise to the top, forming a concentrated layer.

The process where the emulsion becomes too thick and eventually separates into distinct oil and water phases.

In this type of emulsion, tiny oil droplets are dispersed throughout a continuous water phase. Think of milk - fat droplets dispersed in water.

In this type of emulsion, tiny water droplets are dispersed throughout a continuous oil phase. Think of butter - water droplets surrounded by fat.

These agents have a special structure with both water-loving (hydrophilic) and oil-loving (lipophilic) parts. This allows them to connect with both oil and water, holding them together in an emulsion.

This is a type of emulsifier that forms a single layer around the dispersed droplets (oil or water). The layer is thin and acts like a protective shield, preventing separation. This is like a thin film coating the droplets.

This type of emulsifier forms multiple layers around the dispersed droplets. These layers create a more robust barrier, enhancing the stability of the emulsion. This is like many layers around the droplets, stronger protection.

These emulsifiers are solid particles that adsorb to the surface of the dispersed droplets (oil or water), forming a protective layer around them. Imagine tiny particles attaching to the surface, creating a barrier.

The term 'external phase' describes the continuous liquid in an emulsion. This is the liquid that surrounds the droplets. In an O/W emulsion, water is the external phase.

This term is used to describe the dispersed liquid in an emulsion. These are the tiny droplets suspended within the external phase. In a W/O emulsion, water is the internal phase.

This theory suggests that emulsifiers form a thin film around the droplets of the dispersed phase, preventing them from combining.

The theory emphasizes that emulsifiers lower the interfacial tension between oil and water, making it easier to form smaller droplets and stablize the emulsion.

This theory focuses on the force resisting the separation of two immiscible liquids. Lower interfacial tension caused by emulsifiers helps prevent droplet coalescence.

This theory argues that emulsifiers create an electric double layer around the droplets, leading to electrostatic repulsion that prevents them from merging.

This theory proposes that emulsifiers form a monolayer on the surface of the droplets, providing a barrier against coalescence.

The HLB value is a measure of the hydrophilicity-lipophilicity balance of a surfactant. A higher HLB value indicates a more hydrophilic surfactant, while a lower HLB value indicates a more lipophilic surfactant.

The HLB value of a combination of surfactants can be calculated using a weighted average. The weight for each surfactant is its proportion in the mixture.

This theory suggests that emulsifiers are wedge-shaped molecules that align themselves at the interface to create an even, stable mixture.

A single emulsifier is surrounded by a layer of surfactant molecules that prevent coalescence, keeping the droplets separate.

This theory explains that emulsifiers are adsorbed at the interface of oil and water, forming a layer that prevents coalescence.

Higher viscosity of the continuous phase makes it harder for droplets to coalesce, contributing to the emulsion's stability.

Multiple layers of surfactant molecules or hydrophilic colloids surround the oil droplets, creating a barrier that prevents coalescence.

Solid particles are adsorbed at the interface between the two immiscible liquids, forming a physical barrier that stabilizes the emulsion.

The attractive van der Waals force pulls oil droplets together, destabilizing the emulsion. The repulsive electrostatic force pushes droplets apart, stabilizing the emulsion.

Emulsions are not always stable. Over time, smaller droplets coalesce into larger ones, leading to separation into two layers.

Emulsions can improve drug bioavailability, enhance solubility, allow targeted delivery, enhance patient compliance, and improve drug stability.

Surfactants with a pH between 3 and 10, these are generally non-ionic and used in various topical and emulsified applications, such as creams and lotions.

A specialized type of emulsifier that forms a protective layer around droplets of the dispersed phase in an emulsion, stabilizing the mixture.

In the HLB system, a low HLB number indicates a predominantly lipophilic (oil-loving) character. Emulsifiers with low HLB numbers tend to promote the formation of water-in-oil (W/O) emulsions.

Specific examples of non-ionic surfactants commonly used in cosmetics and pharmaceuticals.

A system used to classify emulsifiers based on their balance of hydrophilic (water-loving) and lipophilic (oil-loving) properties. Expressed on a scale from 1 to 18.

In the HLB system, a high HLB number indicates a predominantly hydrophilic (water-loving) character. Emulsifiers with high HLB numbers tend to promote the formation of oil-in-water (O/W) emulsions.

These are natural substances derived from plants or animals, used to act as emulsifiers, stabilizing mixtures of normally incompatible liquids.

These auxiliary agents, such as fatty acids and alcohols, help stabilize emulsions by thickening the mixture, improving its stability.