Use of at least one material chosen from homopolymers and salts thereof of formula (I), defined herein, for moisturizing the skin, mucous membranes and/or keratin fibres, and/or as a moisturizer and/or emollient, for the skin, mucous membranes and/or keratin fibres. The invention also relates to a cosmetic or pharmaceutical composition for moisturizing the skin, mucous membranes and/or keratin fibres, comprising at least one material chosen from homopolymers and salts thereof of formula (I).