The determination of standard deviation requires size
The size-dependence of growth rate of monodisperse silica partimeasurement of a large number of particles, and the standard cles was investigated by analyzing the competitive growth of a deviation of monosize particles is small, so that following dispersion of silica spheres with a bimodal and trimodal size distrithe deviation of particle size distribution as a function of bution. It was found that under the conditions that no new partitime is labored, and it is difficult to accurately measure the cles could be formed, particles with different size grew at the same very small change in deviation. Van Bladderen (4) and Chen rate, demonstrating that the growth was surface reaction limited et al. (7) investigated the size dependence of growth rate process. Under conditions of formation of new particles, however, of monosize silica by following the mean size of a dispersion smaller particles grew faster than larger particles, indicating that of silica particles with a bimodal size distribution; the meathe growth proceeded through diffusion limited process. α§ 1997 Academic Press surement of the mean size is easier and can be done more Key Words: monodisperse; silica particles; growth rate; mechaaccurately than the standard deviation. The same result was nism; tetraethylorthosilicate.
obtained in the growth of monodisperse silica particles that were size-independent, consistent with surface reaction-limited growth mechanisms. Since the same result was obtained 1 To whom correspondence should be addressed. of average diameter of monosize particles as the growth rate 268