Wj. Wu et Gh. Nancollas, KINETICS OF HETEROGENEOUS NUCLEATION OF CALCIUM PHOSPHATES ON ANATASEAND RUTILE SURFACES, Journal of colloid and interface science, 199(2), 1998, pp. 206-211
The heterogeneous nucleation of calcium phosphates including octacalci
um phosphate (Ca4H(PO4)(3). 2.5H(2)O), hydroxyapatite (Ca-5(PO4)(3)OH,
HAP), and fluorapatite ((Ca-5(PO4)(3)F, FAP) on anatase and rutile su
rfaces has been studied in solutions supersaturated with respect to ea
ch phase. Induction periods preceding the initial crystal growth of th
e calcium phosphate phases varied markedly with relative supersaturati
on, At the same relative supersaturation, the induction time for calci
um phosphate nucleation on anatase surfaces was much shorter than that
on rutile surfaces. The surface properties of these titanium oxides w
ere characterized by zeta-potential measurements and by contact angle
measurements involving a thin layer wicking technique. The major diffe
rence between the surfaces was in the Lewis base surface tension param
eters, gamma(s)(-), 48 and 16 mJ m(-2) for anatase and for rutile, res
pectively. (C) 1998 Academic Press.