Amphiphile

Amphiphile (from the Greek αμφις, amphis: both and φιλíα, philia: love, friendship) is a term describing a chemical compound possessing both hydrophilic (water-loving, polar) and lipophilic (fat-loving) properties. Such a compound is called amphiphilic or amphipathic. This forms the basis for a number of areas of research in chemistry and biochemistry, notably that of lipid polymorphism. Organic compounds containing hydrophilic groups at both ends of a prolate molecule are called bolaamphiphilic. Common amphiphilic substances are soaps and detergents.

Structure and Properties

The lipophilic group is typically a large hydrocarbon moiety, such as a long chain of the form CH₃(CH₂)_n, with n > 4. The hydrophilic group falls into one of the following categories:

1. Charged groups
• Anionic. Examples, with the lipophilic part of the molecule represented by an R, are:
• carboxylates: RCO₂⁻;
• sulfates: RSO₄⁻;
• sulfonates: RSO₃⁻.
• phosphates: The charged functionality in phospholipids.
• Cationic. Examples:
• amines: RNH₃⁺.
2. Polar, uncharged groups. Examples are alcohols with large R groups, such as diacyl glycerol (DAG), and oligoethyleneglycols with long alkyl chains.

Often, amphiphilic species have...
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