In this work, we demonstrate that the mechanical dynamics of polymer nanowires prepared by two-photon polymerization direct laser writing lithography is strongly influenced by their viscoelastic characteristics. Bending recovery measurements were carried out on cantilevered nanowires deflected by optical tweezers in a liquid environment. The assumption of purely elastic cantilever response (as defined by Young's modulus of the polymer material) fails to explain the observed overdamped oscillatory motion. A mechanical model is proposed to account for the nanowire viscoelastic behavior. The experimental data indicate that the origin of the nanowire viscous component is twofold. Both the partially cross-linked polymer structure and the solvent penetrating the polymer network contribute to frictional forces inside the nanowire. The present results provide guidance for the future design of nanosized polymer devices operated in a dynamic regime.

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