Calcium Carbonate-Magnetite-Chondroitin Sulfate Composite Microparticles with Enhanced pH Stability and Superparamagnetic Properties

The CaCO3 microparticle growth from supersaturated aqueous solutions in the presence of oleic acid stabilized magnetite nanoparticles as a water-based magnetic fluid and a natural strong-weak polyanion, chondroitin sulfate A, has been investigated. The study follows the microparticle formation characteristics under different relative CaCO3-magnetite-polymer ratios. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to provide high resolution on particle morphology and distribution of magnetite in the composites and flow particle image analysis (FPIA) to evidence their mean size and circularity, whereas X-ray diffraction (XRD) and Raman spectroscopy were used to determine polymorph type and crystallite characteristics. Polymer and magnetite presence in the composite particles was evidenced by energy dispersive X-ray (EDX), TEM, particle charge density, and zeta potential. The magnetic properties of the obtained microparticles were also investigated. The pH stability of the new composites, given by the presence of acid oleic stabilized magnetite nanoparticles and polymer, has been followed by zeta potential variation.