Abstract: The invention relates to a chain end functionalised polymer of formula: ##STR1## in which: the polymer chain (P) is a hydrophobic chain obtained by radical polymerisation of at least one monomer,R represents a hydrogen atom or a linear or branched hydrocarbon chain having 1 to 8 carbon atoms optionally substituted with at least one group selected from CO.sub.2, NH.sub.2, OH or a phenyl group, itself being optionally substituted,A and B, identical or different, each represent a single bond, a saturated or unsaturated linear or branched hydrocarbon chain having from 1 to 16 carbon atoms, it being possible for it to contain an amide bond or a peptide chain having 2 to 4 amino acids, particularly natural amino acids,the NH.sub.2 and/or COOH groups being free or salified.The invention also relates to the use of the above products as surfactants and more particularly as wetting agents, dispersing agents of solid particles and for preparing microdispersions of polymers, in particular microgels and microlatexes.

Abstract: The invention relates to a functionalised polymer of formula:(P)--S--X--F (1)in which:(P) is a hydrophobic polymer chain obtained by radical polymerisation of at least one monomer,S represents sulphur,X represents:a saturated or unsaturated linear or branched hydrocarbon chain having 1 to 6 carbon atoms and substituted with at least one COOH or NH.sub.2 group in the free or salified forma peptide chain constituted of 2 to 4 amino acids, particularly natural amino acids,F represents a COOH or NH.sub.2 group, in the free or salified form,with the exception of the .omega.-dicarboxylic macromonomers resulting from the radical polymerisation of a monomer in the presence of a chain transfer agent constituted of thiomalic acid.

Abstract: Block copolymers denoted by AB from acrylic or methacrylic acid, the corresponding blocks being denoted by A, and from alkyl acrylate or methacrylate with the alkyl chain being C.sub.1 -C.sub.10, the corresponding blocks being denoted by B. Said copolymer blocks are used as wetting and/or dispersing agents for solid particles in an essentially organic medium consisting of a solvent or a mixture of solvents solubilizing the block B.The invention also concerns solid particle dispersions using the above-defined block copolymers.It also concerns compositions, in particular cosmetic compositions, containing said dispersions.