A novel poly(vinyl phosphate) ligand was synthesized as a model of biopolymer ligands containing the OH...O hydrogen bonds and CaHPO4.2H(2)O (brushite) composites with the polymer ligands were also prepared. Successful detection of the polymer ligand binding to the CaHPO4.2H(2)O crystals is achieved by P-31 MAS NMR with 1 pda (single pulse with decoupling and phase cycling) sequence, which enhances P-31 signals of the phosphate polymer having shorter T-1 value.