Surface-tethered chains entangled in a polymer melt: effects on adhesion dynamics.

The adhesion between a polymer melt and substrate is studied in the presence of chemically attached chains on the substrate surface. Extensive molecular dynamics simulations have been carried out to study the effect of temperature, tethered chain density (Sigma), tethered chain length (N(t)), and tensile pull velocity (v) on the adhesive failure mechanisms of pullout and/or scission of the tethered chains. We observe a crossover from pure chain pullout to chain scission as N(t) is increased. The value of N(t) for which this crossover begins approaches the bulk entanglement length N(e) as the temperature is lowered.