A hierarchic build-up of functional nano- and microparticles allows the generation of smart organic supports for metallocene catalysts. Latices, well defined in size and surface structure, are made by emulsion polymerization using poly(ethylene oxide)-containing surfactants. Micron-sized catalyst beads are formed by reversible loading/crosslinking with a metallocene/methylaluminoxane complex. As a result of the network fragmentation during ethylene polymerization, the catalysts achieve very high productivities, hard polyethylene particles and homogeneous distributions of nanometer-sized fragments in the product.