Sulfonated Polymethylsiloxane as an Additive for Selective Calcium Oxalate Crystallization

Abstract

Abstract Sulfonated and fluorescent polymethylsiloxanes (SO 3 H‐PMS) were synthesized, and their effect as additives on in vitro calcium oxalate (CaOx) crystallization was evaluated. SO 3 H‐PMS was prepared by hydrosilylation and sulfonation reactions with poly(dimethylsiloxane‐ co ‐hydrogenmethylsiloxane) (PDMS‐ co ‐PMHS). Several analytical tools were used to investigate the morphology, crystal structure, and chemical contents of the harvested CaOx crystals. Varying the concentration of SO 3 H‐PMS induces a transition of CaOx monohydrate (COM) with expanded multilayer and circular stacked‐sheet morphologies as well as of the bipyramidal CaOx dihydrate (COD) crystals in three crystallization procedures. Energy‐dispersive X‐ray spectroscopy (EDS) and XRD allowed detecting the presence of Si (0.2–1.0°wt.‐%), which stems from SO 3 H‐PMS adsorbed on CaOx, and the selective formation of phases of COM and COD. We demonstrated that the presence of anionic moieties on the SO 3 H‐PMS backbone and their concentration were crucial to control the crystal type, morphology, crystal size, and chemical composition.