Knotting and adsorption of end-grafted active polymers.

Abstract

The adsorption of end-grafted active polymers is significantly influenced by the presence of knots in the polymer. In this study, the adsorption of end-grafted active polymers composed of an active head and an end-grafted passive chain is investigated using Langevin dynamics simulations. The relationship between knots and adsorption is checked by varying the rotational inertia <i>J</i> of the active head. The effect of the active head becomes more pronounced at larger <i>J</i> as the rotational persistence time of the active force on the active head is increased by increasing <i>J</i>. As a result, the adsorption of the active polymer is hindered and the critical surface attraction strength is increased with rising <i>J</i>. The results are primarily attributed to an increased probability of polymer knots <i>P</i>_knot with increasing <i>J</i>. The presence of knots leads to an obvious decrease in the number of adsorbed monomers. Furthermore, we find that the knotting process is slower than the adsorption and the influence of the knotting on the adsorption is relatively weaker than the surface attraction strength. Our simulation results reveal that the increase in the rotational persistence time can increase the probability of knotting and thus weaken the adsorption of active polymer.