EFFECT OF PARTICLE-SIZE ON THE BRIDGING STRUCTURE AND ELASTIC PROPERTIES OF FLOCCULATED SUSPENSIONS

The effect of particle size on the elastic properties of suspensions flocculated by polymer bridging was studied in terms of percolation. When the particle size was in the range of 10-20 nm, the storage modulus was high and almost independent of size. But the suspension of 45-nm silica particles had a very low modulus. One polymer molecule is required to bridge large particles, whereas for small particles one polymer molecule can extend through many bridges. The long-range interaction increases the density of particles which belong to the unbounded network and hence is primarily responsible for high elastic modulus. © 1992.