In one aspect, novel robust electroactive polymers (EAPs) is described, which contract and expand at low voltages to provide for a shape-morphing system, e.g., a prosthetic liner, and potentially entire prosthetic socket, to contract and expand in strategic areas as needed to maintain a comfortable and good fit throughout the day. In some embodiments, as the residual limb changes, these novel robust EAPs can change dynamically as needed to maintain a comfortable, snug fit of the prosthetic liner or socket with the hard shell of the prosthetic socket device. In some embodiments, the EAPs used in prosthetic liners or sockets can also be used to detect pressure as the device is being used, and automatically adjust to maintain fit through a control unit, so that the patient does not even have to stop and adjust his or her device as he or she goes about an active day.