Pore size in one-step swelling and polymerization of monodisperse polymer beads

Crosslinked polystyrene beads were prepared at low swelling ratios by one-s tep swelling and polymerization method. Pore size of the beads was observed based on the GPC calibration curves. It is found that: (1) the pore size i ncreases as the swelling ratio decreases; (2) when a good solvent is used a s the porogen the pore size increases with the crosslinking monomer content ; and (3) at high crosslinking monomer content the pore size does not depen d on the porogen solubility. The effects are discussed in terms of polymer miscibility, including phase separation between the seed and bead polymers. (C) 2000 John Wiley & Sons, Inc.