Living and active polymers in complex environments

This thesis investigates the dynamics of active polymers using experiments on small aquatic worms called Tubifex tubifex. Although the experiments focus on these worms, the broader goal is to understand the physical principles governing a wider class of systems known as active polymers.
Active polymers are long, flexible structures that can move by consuming energy. Examples occur throughout nature, ranging from microscopic filaments such as actin inside living cells to larger organisms like worms and snakes. Compared to the simple spherical particles that are often studied in active matter physics, these elongated systems can bend, twist, and interact strongly with complex environments. This additional complexity gives rise to rich and sometimes unexpected behavior.
In this work, T. tubifex worms serve as an experimental model system for studying active polymer dynamics. Their motion in different environments is analyzed and compared with computer simulations and experiments using simple robotic filaments. By combining these approaches, it becomes possible to distinguish features that are specific to worms from more general behaviors shared by active polymers.
The results show that properties such as flexibility, activity, and interactions with the surrounding environment strongly influence how active polymers move and organize. Together, these findings contribute to a broader framework for understanding active polymers across a wide range of biological and artificial systems.