This study is aimed at developing polymeric actuators using nanofibrous structures made of conductive polymers and gaining insight into the associated phenomena and mechanisms. This roadmap was created due to high specific surface area and porosity provided by the nanofibrous structures both of which allow the ef?cient diffusion of ions and in turn enhance the performance of actuators. In this study, the design of experiments by using the response surface method was used to minimize the polyurethane nanofibers diameter. By electrospinning under optimum conditions, PU nanofibers with diameter of 221 nm were obtained. The chemical and electrochemical polymerization methods were used to synthesis polypyrrole conductive polymer on the surface of PU nanofibers. The effect of different variables including the concentration of the reactants, the time of the polymerization process and the type of dopant in the chemical method, as well as the amount of consumed charge, the polymerization temperature, the solvent and the type of dopant in the electrochemical polymerization on the final properties of nanofibers were investigated. The results indicated that using of lithium bis(trifluoromethanesulfone) imide dopant leads to polyurethane/polypyrrole nanofibers with the lowest surface resistivity in both chemical and electrochemical methods, i.e. 7.39 and 7.68 ?/?, respectively. Also, nanofibers produced using the propylene carbonate as solvent at temperature of -30.0 °C based on the electrochemical polymerization method, exhibited the lowest surface resistivity. Finally, after the production of samples under different conditions and methods, the electrochemical and electrochemo-mechanical properties of the bending actuators were investigated using cyclic voltammetry, coulo-voltammetric, dynamo-voltammetric and coulo-dynamic responses. The nanofibrous actuators produced by using the lithium bis(trifluoromethanesulfone) imide and lithium perchlorate dopants showed the highest and lowest bending actuation with angular displacement of 80 o and 160 o , respectively. It was also observed that the size of electrolyte ions can affect the ion exchange mechanism and the actuation properties of actuators. Using larger ions in a specific ion exchange mechanism results in greater bending movements. For example, using lithium bis(trifluoromethanesulfone) imide electrolyte solution instead of lithium chloride in the same potential range, increased the actuator bending displacement from 31 o to more than 250 o . Immersing in 0.1 M lithium bis(trifluoromethanesulfone) imide electrolyte solution, the produced nanofibrous actuator showed a remarkable bending displacement as high as 720° in a cycle potential ranging between -0.8 V and 0.8 V. Also, the nanofibrous actuators produced by the electrochemical polymerization method with consumed charges of 2.0, 3.0, 4.0 and 5.0 C showed the total bending actuation of 48 o , 153 o , 190 o and 225 o , respectively. Comparison the performance of nanofibrous actuators indicated that the bending movement of sample produced by electrochemical method, i.e. 185 o , is drastically greater than that of sample produced by chemical method, i.e. 80 o . The results also showed that regardless of production method, the produced actuators show a Faradaic behavior and their movement and speed are controlled by the consumed charges and the applied currents, respectively. In this study, two-stage polymerization of polypyrrole on the surface of polyurethane nanofibers was also investigated with the aim of coating the conductive polymer on the surface of entire fibers of electrospun layer by electrochemical method. The actuator produced by this method showed a remarkably enhanced performance with angular displacement of 550 o . Also, with the aim of reducing the potential drop along the length of actuators, the copper electroplating method was used to metalize the surface of polyurethane nanofibres and providing an electrical contact along the entire length of the layer. The surface resistivity of copper-electroplated nanofibers was decreased to 0.71 ?/?, which is about 260 times lower than that of the gold-sputtered specimen. The copper electroplating process improved the final performance of nanofibrous actuator.