A dispersion of polymer particles, the particle containing, on average, one or more living radicals each, the radicals not being chemically protected. Further disclosed is a free radical polymerization process resulting in a dispersion containing polymer particles having on average one or more living radicals. The process involves carefully regulating the polymerization conditions to produce small size particles under monomer-starved conditions containing, on average, more than one living radical in every particle. These living polymer radicals can be further reacted to form polymers with a controlled architecture.