The invention relates to a polymer-clay composite material comprising clay nanoparticles and a polymer, and wherein (a) the polymer comprises phosphate and/or phosphonate ligands; or (b) the polymer-clay composite further comprises linker molecules comprising a phosphate or phosphonate ligand, wherein the linker molecules are arranged to be anchored to the polymer. The invention further relates to organoclays, BMP-clay composite material. Uses, treatments, and manufacturer of the material are also provided.