Configuration dynamics of active polymer chain with actively driven regions

Langevin dynamics simulations were implemented to investigate the configuration dynamics of a polymer chain in two-dimensional space. The polymer chain we studied consists of two types of beads: passive Brownian particles and active Brownian particles. Special attention is given to the dependence of the radius of gyration Rg of the polymer chain on the ratio of active sites Φ. We found that as the ratio of active sites Φ increases, the radius of gyration Rg of a flexible chain increases monotonically, whereas for a semi-flexible polymer chain, the radius of gyration Rg exhibits a non-monotonic variation. Moreover, when the ratio of active sites Φ is fixed, the radius of gyration Rg of the polymer chain also exhibits a non-monotonic variation as the activity increases. Analysis reveals that it is the interplay between two effects of active semi-flexible chain, one is the stretching effect of the polymer chain due to rigidity, and the other is the folding effect of the polymer chain due to active sites. Once the ratio of active sites is large enough, the activity acts as an effective high temperature, increasing the polymer chain's radius of gyration Rg.