Lanthanum complex of a multifunctional water-soluble siloxane compound—Synthesis, surface activity and applications for nanoparticles stabilization

A tris(hydroxymethyl)aminomethane-modified polysiloxane has previously been investigated for surface properties and valuable practical applications have been proposed, including nanoparticle stabilization, complexing of 3d metals, micellar solubilization of drugs and water dispersion of metal oxide nanoparticles. In this article we show the ability of this multifunctional polymer to bind 4f metals. A polymeric lanthanum complex was obtained and characterized. The most probable structure was assigned based on ESI-MS and FT-IR, using data obtained with a homologous disiloxane model compound. The polymeric lanthanum complex shows surface activity, with a CMC value of 150 mg/L. Self-assembling in water was also studied by DLS and TEM, which revealed formation of vesicles. The La complex was tested with very good results for polymer nanoparticle stabilization. Polycarolactone nanoparticles of ca. 150 nm with long-term stability (Zeta potential = 55 mV) were obtained. The aqueous dispersion of organic-coated metal oxide nanoparticles was also successful.