Published online by Cambridge University Press: 25 February 2011
Stokes settling in viscous gels was used as a method for classifying mixed powders of silicon crystallites and amorphous silicon; Quantum-size materials derived from porous silicon were encapsulated and trapped in the viscous gels. After complete gelation the matrix retained size gradations developed during Stokes settling, thus yielding a new variant of functionally gradient materials (FGM). Production and rheological properties of the sol and preparation of specimens for centrifuging are discussed. The relative position of particles with various sizes are quantitatively interpreted in relation to the increase in gel viscosity with time.