Study of Polyelectrolyte Complex Nanoparticles as Novel Templates for Biomimetic Mineralization

Needle-like water-soluble polyelectrolyte complex nanoparticles (PEC NPs), consisting of sodium carboxylmethyl cellulose (CMCNa) and poly(methacryloxyethyl trimethyl ammonium chloride) (PDMC), were studied as novel templates for biomimetic mineralization. Barium acetate and sodium sulfate solutions were added simultaneously into CMCNa/PDMC polyelectrolyte complex (PEC) solutions as BaSO4 precursors. Spherical BaSO4 crystals with unique annual ring cross section were synthesized in different concentrations of PEC solution. Energy dispersive X-ray spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric analysis (TGA) showed that these crystals were composed of ca. 90-95 wt % BaSO4 and 5-10 wt % PEC NPs. Study of ionic strength effect on PEC mineralization revealed that the rigid needle-like structure of PEC is responsible for BaSO4 morphology. In addition, the mineralization differences between CMCNa and CMCNa/PDMC PEC are discussed.