Graft copolymers consisting of the polyacetal backbone substituted with -COO- groups and poly(oxyethylene) (POE) side chains in different proportions were synthesized, and their efficiency as modifiers of the processes occurring at the interphase between inorganic particles and the surrounding aqueous phase was studied. The series of double hydrophilic graft copolymers (DHGC) was obtained differing in the length of the main chain, the number of carboxylate groups, and the number of POE side chains in the macromolecule. Studies of the effect of DHGC on the stability of aqueous calcium carbonate (CaCO3) suspensions and on the shape and size of the CaCO3 crystals formed in the presence of DHGC allowed us to draw some conclusions concerning the effect of the structure of DHGC on their efficiency as modifiers of the processes occurring at the interphase between inorganic particles and the surrounding aqueous phase. (C) 2004 Wiley Periodicals, Inc.