The application provides a method of producing a comb polymer comprising the steps of: (a) Providing: (i) a plurality of monomers which are linear, branched or star-shaped, substituted or non-substituted, and have an olefinically unsaturated moiety, the olefinically unsaturated moiety being capable of undergoing addition polymerisation; (ii) an initiator compound; the initiator compound comprising a homolytically cleavable bond. (iii) a catalyst capable of catalysing the polymerisation of the monomer; and (b) Causing the catalyst to catalyse, in combination with the initiator, the polymerisation of a plurality of the monomers to produce the comb polymer. Catalysts and polymers obtainable by the process are also provided. Preferably, the comb polymer is capable of binding proteins and may be produced from monomers which are alkoxy polyethers, such as poly(alkyleneglycol) or polytetrahydrofuran.