Induction of hydroxycarbonate apatite formation on polyethylene or alumina substrates by spherical vaterite particles deposition

Abstract

Hydroxycarbonate apatite (HCA) layers were formed on polyethylene (PE) or alumina substrates by depositing spherical sub-micron vaterite particles and then immersing in simulated body fluid (SBF). HCA formation on vaterite‐coated PE was faster than that on coated alumina (3days for PE and 7days for alumina). The adsorption of phosphate ions on the vaterite particles in SBF was studied by monitoring changes in the concentration of phosphorous in SBF and the surface charges of vaterite during the SBF immersion. The phosphorous concentration of SBF in which a vaterite-coated PE was immersed for 1h was lower than that in which a vaterite-coated alumina was immersed. Zeta potential of the vaterite surface deposited on PE drastically decreased after 1h immersion in SBF. The vaterite particles deposited on each substrate immediately adsorbed phosphate ions in SBF. The amount of ions adsorbing on the vaterite surfaces deposited on PE was larger than that on alumina. This was attributed to differences in the surface charges between PE (−16mV) and alumina (+38mV). The phosphate adsorption was predominantly electrostatic therefore related to the surface charge of vaterite particles. The surface charges of substrates may affect the charge of vaterite particles.