Abstract: Branched polymers resulting from homopolymerization or copolymerization of monomers of formula I: ##STR1## R is H or a lower alkyl group of C.sub.1 to C.sub.3 ; Z is O or NH; B has the formula:--(CH.sub.2).sub.q1 --Z.sub.1 --(CH.sub.2).sub.2 --in which .sub.q1 and q.sub.2 are integers greater than or equal to 1, the sum of which is less than approximately 32 and Z.sub.1 represents a single bond or O, S, NH, CO or CO--NH; (AA).sub.p represents a peptide radical comprising p linked aliphatic alpha-aminoacids, bound at B by its carboxyl group, each amino acid comprising less than 15 carbon atoms and being possibly substituted at one carbon atom of the chain by a carboxylic acid or ester, amide or amine group, the terminal amine group of the peptide radical being possibly acylated by a R'CO group, R' being an alkyl radical comprising 1 to 4 carbon atoms, or by any other group stable under the conditions of synthesis; and p represents a number ranging between 1 and 200.

Abstract: The lipopeptides according to the invention are amphiphatic and consist of a hydrophobic chain containing from about 8 to 24 carbon atoms and of a peptide chain which is hydrophilic or has been rendered hydrophilic.They are applied, in particular, to emulsions of immiscible media and to the preparation of lyotropic liquid crystals.