The wetting dynamics of molten thermoplastic polymers, which are known to influence the force balance of the triple line, are not understood properly despite their importance in many industrial processes. In particular, the influence of the molecular weight Mn on the polymer dynamic wetting behavior is still unclear. In this work, we investigate how the dynamic equilibrium of the moving contact line between poly(ethylene glycol) and cellulosic substrates is influenced by Mn. After a careful assessment of the rel-evant material properties, dynamic wetting experiments are conducted using the Wilhelmy method. Our investigations reveal an influence of Mn on the evolution of all of the measured quantities. The dynamic wetting behavior is shown to relate to the polymer chain size, and to display a transition at the critical weight of entanglement Mc . This study should help defining guidelines for formulating and choosing polymers for various processes, such as composites manufacturing.(c) 2023 Elsevier Ltd. All rights reserved.