HETEROGENEOUS NUCLEATION OF CALCIUM PHOSPHATES ON SOLID-SURFACES IN AQUEOUS-SOLUTION

The heterogeneous nucleation of calcium phosphates on solid surfaces o f poly(methyl methacrylate) (PMMA), poly(tetrafluoroethylene-co-hexafl uoropropylene) (FEP), silicone rubber, mica, and radiofrequency glow d ischarge (RFGD)-treated PMMA, FEP, and silicone rubber has been studie d in solutions supersaturated with respect to hydroxyapatite. The surf ace properties of the substrates were characterized by contact angle m easurements. For the RFGD-treated surfaces, the Lifshitz-Van der Waals surface tension component changes very little, but the Lewis acid-bas e surface tension parameters vary greatly depending upon the materials . With scanning electron microscopy, nucleation of calcium phosphates was observed only on the surfaces: mica, RFGD-treated PMMA and FEP, wi th relatively high values of the Lewis base surface tension parameter. The more hydrophobic surfaces having low Lewis acid-base surface tens ions, untreated PMMA and FEP, silicone rubber, and even RFGD-treated s ilicone rubber showed no nucleation. (C) 1997 John Wiley & Sons, Inc.