KINETICS OF ANCHORING OF POLYMER-CHAINS ON SUBSTRATES WITH CHEMICALLYACTIVE-SITES

We consider dynamics of an isolated polymer chain with a chemically ac tive end-bead on a two-dimensional (2D) solid substrate containing imm obile, randomly placed chemically active sites (traps). For a particul ar situation when the end-bead can be irreversibly trapped by any of t hese sites, which results in a complete anchoring of the whole chain, we calculate the time evolution of the probability P-ch(t) that the in itially nonanchored chain remains mobile until time t. We find that fo r relatively short chains P-ch(t) follows at intermediate times a stan dard-form 2D Smoluchowski-type decay law In P-ch(t)similar to - t/ln(t ), which crosses over at very large times to the fluctuation-induced d ependence In P-ch(t)similar to - t(1/2), associated with fluctuations in the spatial distribution of traps. We show next that for long chain s the kinetic behavior is quite different; here the intermediate-time decay is of the form In P-ch(t)similar to - t(1/2), which is the Smolu chowski-type law associated with subdiffusive motion of the end-bead, while the long-time fluctuation-induced decay is described by the depe ndence In P-ch(t)similar to -t(1/4), stemming out of the interplay bet ween fluctuations in traps distribution and internal relaxations of th e chain. [S1063-651X(98)01611-0].