  We computationally investigate the active transport of tangentially-driven
polymers with varying degrees of flexibility and activity in two-dimensional
square lattices of obstacles. Tight periodic confinement induces notable
conformational changes and distinct modes of transport for flexible and stiff
active filaments. It leads to localization and caging of flexible polymers
inside the inter-obstacle pores, while promoting more elongated conformations
and enhanced diffusion for stiff polymers at low to moderate activity levels.
The migration of flexible active polymers occurs via hopping events, where they
unfold to move from one cage to another. In contrast, stiff chains travel
mainly in straight paths within inter-obstacle channels, while occasionally
changing their direction of motion. Both the duration of caging and persistent
directed migration within the channels decrease with increasing the activity
level. As a consequence, at high active forces polymers overcome confinement
effects and transport within inter-obstacle pores as swiftly as those in free
space. We explain the center of mass dynamics of semiflexible polymers in terms
of active force and obstacle packing fraction by developing an approximate
analytical theory.
