NANOPARTICLE HYDROXYAPATITE CRYSTALLIZATION CONTROL BY USING POLYELECTROLYTES

Abstract

The synthesis of advanced inorganic materials such as biomedical devices, catalysis, ceramics, optical and electronic films require crystallization strategies that provide control over the size, structure, orientation and morphology of the forming crystal. In biomineralization, inorganic crystals form under the full control of structure directing polymers, such as proteins and polysaccharides. In this work we present a facile way to produce HAP nanoparticles by wet chemical synthesis in the presence of polyelectrolytes under strictly controlled temperature, pH, and atmospheric conditions. The constant-composition method has been used to study the influence of polyelectrolytes on the kinetics of crystal growth of hydroxyapatite (HAP) on HAP seed crystals at pH 7.4 and 37 degrees C. The results indicate that polyelectrolyte concentration and the larger number of negatively charged functional groups markedly affect the growth rate. The fit of the Langmuir adsorption model to the experimental data supports a mechanism of inhibition through molecular adsorption of polymers on the surface of growing crystals.