Dewetting of a thin polymer film probes the stress and mobility frozen in during preparation. A companion theory showed that self-propulsion enhances the elastic modulus of flexible active films through grip forces at entanglements. Here I derive the semiflexible case relevant to biological filaments. Because a semiflexible chain reorients along its tube, grip forces from successive segments add in quadrature. At fixed persistence length ${\ell }_p$ and propulsion strength, this changes the activity parameter $\alpha$ (the ratio of active to passive plateau modulus) from $\alpha \propto L$ to $\alpha \propto {\left({\ell }_{p}L\right)}^{1/2}$ in the chain contour length $L$, and the active viscosity from $L^2$ to $L^{3/2}$, a scaling class lying between the passive $\left(L^3\right)$ and flexible active $\left(L^2\right)$ melts. The biexponential relaxation is retained; an exact relation between the fast-channel weight and $\alpha$ renders three observables stiffness-independent, while the kink in sequential nucleation and hole growth dynamics fixes the propulsion speed alone, while its amplitude ratio returns the activity parameter and hence the stiffness. A parameter-free wormlike-chain numerical simulation confirms the quadrature scaling and its crossover to the coherent limit, and published T. Tubifex worm rheology qualitatively supports the two-channel picture.

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• Polymer entanglement
• Polymer thin films
• Polymer scaling theory