Amphiphilicity (otherwise diphilicity ) is a property of molecules of substances (usually organic) that have both lyophilic (in particular, hydrophilic ) and lyophobic ( hydrophobic ) properties [1] .
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Description
Lyophilicity and lyophobicity (from the Greek. Lýo - dissolve, philéo - I love and phóbos - fear) - qualitative characteristics of the intermolecular interaction of the substance and the environment in which it is located. If the substance and the medium are close in structure to the molecules or the molecules of the substance strongly interact with the medium, for example, form hydrogen bonds, then they speak about lyophilicity, and with a weak interaction of the substance and the medium - about lyophobicity. In cases where water serves as a medium, the terms “hydrophilicity” and “hydrophobicity” (from Greek hydro - water) are usually used [1] .
As a rule, the hydrophobic part of the amphiphilic compound is a long unbranched hydrocarbon chain CH 3 (CH 2 ) n , where n> 4, and the hydrophilic part is a polar functional group of the type COOH or a small ion, for example, COO - or N (CH 3 ) 3 + . The existence of the polar and nonpolar parts of the molecule promotes the aggregation of particles with the formation of micelles , bilayers, and other structures (see Fig.). Surfactants, lipids , many peptides , proteins , polymers possess amphiphilic properties [1] .
In particular, phospholipids as well as lipoproteins are amphiphilic substances. Due to the amphiphilic properties of phospholipids when interacting with water, they form micelles , liposomes and lipid bilayers. Proteins have amphiphilic properties, since they usually contain amino acids with hydrophilic and hydrophobic radicals. Amphiphilicity of proteins affects the tertiary and quaternary structures of molecules formed by them.
Since amphiphilic substances in solution are capable of forming various supramolecular structures: monolayers , micelles, liposomes, etc. (see Fig.), They are widely used for the synthesis of nanoparticles of various nature, as well as films and membranes. In addition, they are often used as a protective shell for nanoparticles [1] .
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See also
- Hydrophilicity
- Hydrophobicity
Notes
- ↑ 1 2 3 4 5 Eremin Vadim Vladimirovich. Amphiphilic “Dictionary of nanotechnological terms” . Rusnano . Date of treatment December 18, 2011. Archived March 28, 2012.