Graduate
  1. Physical Chemistry  1.1. Thermodynamics  1.1.1. Laws of Thermodynamics  1.1.2. Enthalpy and heat capacity  1.1.3. Entropy and free energy  1.1.4. Phase Equilibrium  1.1.5. Statistical thermodynamics  1.1.6. Thermodynamic cycle  1.1.7. Fugacity and activity  1.2. Quantum Chemistry  1.2.1. Principles of quantum mechanics  1.2.2. Schrödinger Equation  1.2.3. Particle in a box  1.2.4. Operators and eigenvalues  1.2.5. Atomic orbitals  1.2.6. Molecular orbital theory  1.2.7. Perturbation theory  1.2.8. Valence bond theory  1.2.9. Hybridization and chemical bonding  1.3. Chemical kinetics  1.3.1. Rate laws and reaction mechanisms  1.3.2. Collision theory  1.3.3. Transition state theory  1.3.4. Enzyme Kinetics  1.3.5. Chain Reactions and Polymerization  1.3.6. Photochemical reactions  1.4. Statistical mechanics  1.4.1. Partitioning functions  1.4.2. Molecular distribution functions  1.4.3. Boltzmann Distribution  1.4.4. Bose–Einstein and Fermi–Dirac statistics  1.5. Spectroscopy  1.5.1. Rotational Spectroscopy  1.5.2. Vibrational Spectroscopy  1.5.3. Electronic Spectroscopy  1.5.4. Nuclear magnetic resonance spectroscopy  1.5.5. Mass Spectrometry  1.5.6. Raman Spectroscopy  1.5.7. Electron paramagnetic resonance spectroscopy  1.6. Surface and colloidal chemistry  1.6.1. Absorption isotherm  1.6.2. Surface tension and wetting  1.6.3. Colloidal Stability  1.6.4. Catalysis  1.6.5. Emulsions and micelles  1.7. Electrochemistry  1.7.1. Nernst equation  1.7.2. Electrochemical cells  1.7.3. Conductivity and mobility  1.7.4. War  1.7.5. Fuel cells  1.7.6. Electrolysis
  2. Organic chemistry  2.1. Reaction mechanism  2.1.1. Nucleophilic substitution reactions  2.1.2. Electrophilic addition reactions  2.1.3. Elimination reactions  2.1.4. Rearrangement reactions  2.1.5. Radical reactions  2.1.6. Pericyclic reactions  2.2. Spectroscopy and structural determination  2.2.1. UV-Vis Spectroscopy  2.2.2. IR Spectroscopy  2.2.3. NMR Spectroscopy  2.2.4. Mass Spectrometry  2.2.5. X-ray crystallography  2.3. Stereoscopic  2.3.1. Chirality and optical activity  2.3.2. Structural analysis  2.3.3. Geometrical isomerism  2.3.4. Dynamic Stereochemistry  2.4. Organometallic Chemistry  2.4.1. Organolithium and organomagnesium reagents  2.4.2. Palladium-catalyzed cross-coupling reactions  2.4.3. Transition Metal Complexes  2.4.4. Metal–carbon bond  2.5. Polymer chemistry  2.5.1. Polymerization mechanism  2.5.2. Polymer Characteristics  2.5.3. Biodegradable Polymer  2.5.4. Conducting polymer  2.5.5. Supramolecular polymers  2.6. Medicinal chemistry  2.6.1. Drug design and development  2.6.2. Pharmacokinetics and pharmacodynamics  2.6.3. Structure-activity relationships  2.6.4. Molecular docking and drug screening
  3. Inorganic chemistry  3.1. Coordination chemistry  3.1.1. Crystal field theory  3.1.2. Ligand field theory  3.1.3. Spectrochemical Series  3.1.4. Chelation and stability  3.2. Organometallic Chemistry  3.2.1. Metal Carbonyls  3.2.2. Catalysis by organometallic complexes  3.2.3. Metallocenes  3.3. Bio-inorganic chemistry  3.3.1. Metalloproteins and enzymes  3.3.2. The role of metals in biological systems  3.3.3. Metal ion transport and storage  3.4. Solid state chemistry  3.4.1. Crystal Structures  3.4.2. Band theory of solids  3.4.3. Superconductors  3.4.4. Defects in the crystal  3.5. Lanthanides and Actinides  3.5.1. Electronic configuration in lanthanides and actinides  3.5.2. Coordination chemistry of the lanthanides  3.5.3. Magnetic Properties of Lanthanides
  4. Analytical chemistry  4.1. Chromatography  4.1.1. Gas Chromatography  4.1.2. High Performance Liquid Chromatography  4.1.3. Thin Layer Chromatography  4.2. Spectroscopic Techniques  4.2.1. Atomic absorption spectroscopy  4.2.2. X-ray diffraction  4.2.3. Inductively coupled plasma spectroscopy  4.3. Electroanalytical methods  4.3.1. Potentiometry  4.3.2. Voltammetry  4.3.3. Colometry  4.4. Mass Spectrometry  4.4.1. Ionization Technique  4.4.2. Fragmentation Pattern  4.5. Chemometrics  4.5.1. Multidisciplinary analysis  4.5.2. Machine Learning in Chemistry
  5. Theoretical and Computational Chemistry  5.1. Molecular dynamics simulation  5.1.1. Force fields and energy minimization  5.1.2. Monte Carlo simulation in molecular dynamics simulations  5.2. Quantum chemical methods  5.2.1. Hartree–Fock theory  5.2.2. Density functional theory  5.2.3. Semi-empirical methods  5.3. Computational drug design  5.3.1. Molecular Docking  5.3.2. QSAR Modeling  5.3.3. Virtual Screening
  6. Biochemistry  6.1. Enzyme Kinetics  6.1.1. Michaelis-Menten kinetics  6.1.2. Inhibition mechanism  6.2. Metabolism and Bioenergetics  6.2.1. Glycolysis  6.2.2. Citric acid cycle  6.2.3. Electron transport chain  6.3. molecular Biology  6.3.1. DNA replication and repair  6.3.2. Protein synthesis  6.3.3. Gene Regulation  6.4. Structural Biochemistry  6.4.1. Protein Folding  6.4.2. Membrane Biophysics
  7. Environmental Chemistry  7.1. Atmospheric Chemistry  7.1.1. Greenhouse gases  7.1.2. Ozone depletion  7.1.3. Air pollutants and smoke  7.2. Water Chemistry  7.2.1. pH and water hardness  7.2.2. Wastewater treatment  7.2.3. Aquatic Chemistry  7.3. Soil Chemistry  7.3.1. Heavy metal contamination  7.3.2. Soil pH and Buffering  7.3.3. Nutrient cycling  7.4. Toxicology and Chemical Safety  7.4.1. Toxicokinetics  7.4.2. Risk Assessment in Toxicology and Chemical Safety in Environmental Chemistry  7.4.3. Effects of pollutants on the environment

Graduate → Physical Chemistry → Surface and colloidal chemistry ↓


Emulsions and micelles


Both emulsions and micelles are fascinating topics in the field of colloidal chemistry, and they play a vital role in many industrial applications and natural processes. To delve deeper into these topics, it is important to understand their underlying principles, formation mechanisms, and real-world applications.

Understanding colloids

Before discussing emulsions and micelles in detail, it is important to understand what colloids are. A colloid is a mixture in which one substance, finely dispersed as tiny particles, is suspended within another substance. Colloidal particles have a size between 1 nanometer and 1 micrometer. These particles are larger than molecules but smaller than particles seen in suspensions, allowing them to remain evenly distributed without clumping.

Emulsion: A special type of colloid

Emulsions are specific types of colloids that form when two immiscible liquids are mixed, that is, liquids that do not naturally mix together. These usually include oil and water. The process of emulsification involves dispersing one liquid as tiny droplets within another liquid.

Types of emulsions

There are mainly two types of emulsions:

  • Oil-in-water (O/W) emulsions: These emulsions contain oil droplets dispersed in a continuous water phase. They are commonly used in food products such as milk and cream, and in pharmaceuticals.
  • Oil in water (W/O) emulsions: Here, water droplets are dispersed in a continuous oil phase. These emulsions are common in products such as butter and some cosmetic formulations.

Below is a visual example of an oil-in-water emulsion:

Water Phase Oil drops

Formation and stability of emulsions

The formation of emulsions often requires mechanical stirring or homogenization, which helps break up one liquid into smaller droplets within the other. However, emulsification alone is not always enough; emulsions must be stabilized to prevent them from separating over time. To achieve this stability, emulsifiers or surfactants are used.

R-SO4^- Na^+

In this formula, R represents the hydrophobic tail, and SO4^- is the hydrophilic head. Together, these molecules reduce the surface tension at the oil and water interface, stabilizing the emulsion by preventing the droplets from coming together.

Emulsions are used in many products, from foods to medicines, because of their ability to combine different functional ingredients in a uniform way. For example, in the pharmaceutical industry, emulsions are able to deliver drugs that would otherwise be insoluble in water, ensuring they are bioavailable.

Micelles: A molecular assembly

Micelles are another fascinating structure in surface and colloidal chemistry. These are formed by surfactant molecules, which have both hydrophilic (water-loving) and hydrophobic (water-repelling) parts. When surfactant molecules are present in sufficient quantities in water, they self-assemble into spherical aggregates, known as micelles.

Structure of micelles

The formation of micelles can be understood by examining the behavior of surfactant molecules:

  • Hydrophilic heads: These parts of the molecules want to remain in contact with water.
  • Hydrophobic tails: These parts avoid water and prefer to stay grouped together.

When the concentration of surfactant reaches a certain level known as the critical micelle concentration (CMC), the hydrophobic tails cluster inwards while the hydrophilic heads face outwards, forming a structure like this:

The centre of the micelle, where the tails are compressed, is hydrophobic and effectively traps oils and other nonpolar substances, a principle used in cleaning products such as soaps and detergents.

Applications of micelles

Micelles are widely used in various fields:

  • Cleaning agents: Soaps and detergents contain surfactants that form micelles around oil and grease, allowing them to be removed with water.
  • Drug delivery: Micelles can encapsulate hydrophobic drugs, increasing their solubility and distribution in the body. This capability is particularly promising for targeted delivery systems in nanomedicine.

Comparative analysis: emulsions and micelles

Although both emulsions and micelles contain surfactants and are related by the concepts of phase separation and surface tension, they differ in structure, manufacture, and use.

  • Structure: Emulsions are composed of one liquid dispersed within another liquid, while micelles resemble single-layer spheres formed by surfactant molecules in water.
  • Formation: Emulsions require energy input, such as stirring or mixing, to combine immiscible liquids, whereas micelles are formed spontaneously in CMCs.
  • Size: Emulsions are typically large, droplet-based colloids, whereas micelles are much smaller clusters at the molecular level.
  • Applications: Emulsions are used to combine different liquid phases in products such as lotions and medications, while micelles play an important role in cleaning and drug delivery.

Conclusion

Emulsions and micelles underscore the subtle role of chemistry at the interface and colloidal scale, demonstrating how slight manipulations of molecular affinity can drastically alter the properties of materials. Their underlying principles underpin both everyday products and advanced pharmaceutical technologies, illustrating how surface and colloidal chemistry translate into practical solutions.


Graduate → 1.6.5


U
username
0%
completed in Graduate

← Prev (1.6.4)
Catalysis
Next (1.7) →
Electrochemistry

Comments 



Emulsions and micelles

https://www.chemistryelite.com/g/1.6.5?ceal=en