Braiding two polymer chains into a double helix with a molecular rotor

inherently challenging due to random Brownian motion. Although directional motion at the molecular scale has been widely demonstrated, its translation into controlled molecular architectures remains limited. Here, we show that a rotary molecular motor can actively direct the assembly of two polymer chains into a double-helical structure. Two poly(ethylene oxide) chains were covalently anchored to an overcrowded alkene-based motor, whose unidirectional rotation 20 is driven by UV-light. The resulting motor-induced entanglement was probed by single-molecule force spectroscopy, revealing distinct mechanical signatures, including force plateaus and twiststretch coupling behaviour, consistent with the formation of intertwined polymer chains in a doublehelical arrangement reminiscent of DNA. These findings demonstrate how molecular rotary motion can be harnessed to induce controlled long-range mechanical organization, enabling the 25