Towards Nano-Biomimetic Muscles: Polyacrylonitrile Nanofibers

摘要

The important characteristics of the activated Polyacrylonitrile (PAN) fibers are its ability to change in length more than 100% and its comparable strength to human muscle. As against to other reported works in which commercially available fibers with diameters in the range of 10s of micrometers were used, here we tried to study the phenomenon in a few hundred nanometer diameter fibers. These fibers are expected to have smaller response times and higher deformations than conventional micronsized fibers. These PAN fibers were made by electrospinning. The fibers are placed in a solution and the change in the shape of the fibers was observed with change in pH. The fibers contracted in acidic solution and expanded in basic solution similar to that reported in the literature. Here we measured the variation in the diameter of the fibers using E-SEM while the change in pH is taking place. It appears that a variation of more than 100% was observed similar to that observed with conventional fibers of diameter ranging from 10 to 50 μm. These results provide a potential in developing fast actuating PAN muscles and linear actuators, and muscle structures similar to sarcomere/myosin/actin-like assembly. In addition, we were able to observe giant volume changes more than 1,000% with conventional PAN fibers.