Surface active agents lipophobic group

Surfactants, sometimes called surface active agents or detergents, are amphiphilic materials which contain both apolar, hydrophobic (lipophilic) and polar, hydrophilic (lipophobic) groups (Hartley, 1948, 1977 Fendler and Fendler, 1975 Fendler, 1982 Lindman and Wennerstrom, 1980 Sudholter... 

In their similar action on the cell membrane the tyrocidines, gramicidins and the polymyxins resemble other surface active agents. Like these, they contain also lipophilic and lipophobic groups, which, as has been revealed by studies on gramicidins, may be separated in the molecule by being fixed on different sides of the molecular plane. 

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