Detergent
 |
This article is a stub. Please help Sciencemadness Wiki by expanding it, adding pictures, and improving existing text.
|
A detergent is a surfactant or a mixture of surfactants with cleansing properties when in dilute solutions.
Depending on the formulation, detergents can be solid (powder) or liquid.
Contents
General
Detergents are a group of compounds with an amphiphilic structure, where each molecule has a hydrophilic (polar) head and a long hydrophobic (non-polar) tail. The hydrophobic portion of these molecules may be straight- or branched-chain hydrocarbons, or it may have a steroid structure. The hydrophilic portion is more varied, they may be ionic or non-ionic, and can range from a simple or a relatively elaborate structure. Detergents are surfactants since they can decrease the surface tension of water. Their dual nature facilitates the mixture of hydrophobic compounds (like oil and grease) with water. Because air is not hydrophilic, detergents are also foaming agents to varying degrees.
Detergent molecules aggregate to form micelles, which makes them soluble in water. The hydrophobic group of the detergent is the main driving force of micelle formation, its aggregation forms the hydrophobic core of the micelles. The micelle can remove grease, protein or soiling particles. The concentration at which micelles start to form is the critical micelle concentration (CMC), and the temperature at which the micelles further aggregate to separate the solution into two phases is the cloud point when the solution becomes cloudy and detergency is optimal.
Laundry and commercial detergents generally contain builders (50% by weight, approximately), surfactants (15%), bleach (7%) (sodium perborate or sodium percarbonate), enzymes (2%), soil antideposition agents, foam regulators, corrosion inhibitors, optical brighteners, dye transfer inhibitors, fragrances, dyes, fillers and formulation aids.
Types
- Anionic detergents: the most common form of detergents, typically represented by alkyl and alkylbenzene sulfonates, such as sodium dodecyl sulfate, sodium dodecylbenzenesulfonate.
- Cationic detergents: similar to anionic ones, but quaternary ammonium replaces the hydrophilic anionic sulfonate group. The ammonium sulfate center is positively charged.
- Non-ionic detergents: characterized by their uncharged, hydrophilic headgroups. Typical non-ionic detergents are based on polyoxyethylene or a glycoside.
- Amphoteric detergents: Amphoteric or zwitterionic detergents have zwitterions within a particular pH range, and possess a net zero charge arising from the presence of equal numbers of +1 and −1 charged chemical groups.
Availability
Detergents can be bought from most stores. Special detergents can be bought online or from cleaning product suppliers.
Projects
- Cleaning labware
- Washing clothes
Safety and handling
Detergents are not harmful, though direct contact might cause irritation to the skin, eyes or mouth.
FOR THE LOVE OF GOD, DO NOT EAT TIDE PODS!
Detergents can be safely poured down the drain.
