Formation and equilibrium properties of living polymer brushes

Polydisperse brushes obtained by reversible radical chain polymerization re action onto a solid substrate with surface-attached initiators are studied by means of an off-lattice Monte Carlo algorithm of living polymers (LP). V arious properties of such brushes, like the average chain length and the co nformational orientation of the polymers, or the force exerted by the brush on the opposite container wall, reveal power-law dependence on the relevan t parameters. The observed molecular weight distribution (MWD) of the graft ed LP decays much more slowly than the corresponding LP bulk system due to the gradient of the monomer density within the dense pseudobrush which favo rs longer chains. Both MWD and the density profiles of grafted polymers and chain ends are well fitted by effective power laws whereby the different e xponents turn out to be mutually self-consistent for a pseudobrush in the s trong-stretching regime. The specific values are, however, inconsistent wit h a standard self-consistent field theory of pseudobrushes which predicts a much softer mushroomlike layer. (C) 2000 American Institute of Physics. [S 0021-9606(00)51503-7].