Electroactive polymer-based articulation mechanism for multi-fire surgical fastening instrument

Methods and devices are provided for effecting movement of one or more components of a multifire device, such as a clip applier, hernia tacker, or skin stapler. In one exemplary embodiment, a surgical fastening instrument is provided having an elongate shaft with an end effector coupled thereto and adapted to apply one or more surgical fasteners to tissue. An electrically expandable and contractible actuator, such as an electroactive polymer actuator, can be used to drive a fastener advancing or forming assembly through the elongate shaft, thereby driving a surgical fastener into tissue. In another embodiment, an electrically expandable and contractible actuator, such as an electroactive polymer actuator, can be used to effect movement of an articulation joint formed between the elongate shaft and the end effector.