Actuators And Memory Devices Based On Nano-materials Of Conducting Polymers

Ever since the discovery of conducting polymers 30 years ago, these materials have been widely applied in solar cells, photo-electrical devices, super capacitors, sensors, memory devices, actuators and artificial muscles, due to their unique optical, electrical, mechanical and magnetic properties. Nanostructures and nanocomposites of conducting polymers have the properties of conducting polymers and improved properties of nano-materials. Thus, devices based on conducting polymer nano-structures and theirs nano-composites were studied in this thesis. Two typical devices were focused: all polymeric solid actuator based on conducting polymer nano-wires and memory devices based on conducting polymer/gold nanoparticles composites.A two-step approach was employed for fabricating the ABA 3-layerd actuators, which can work in air. Layer"A"is poly-pyrrole nano-sheet with a lot of interstices which causes the close occlusion to Layer"B". Thus, the actuator shows good actuation (displacement 0.1 mm/s), and great mechanical properties (tensile strength 3.1 MPa). Comparing to actuators based on single wall carbon nanotubes, this actuator exhibits comparable performance with relatively low cost.On the other hand, memory devices based on electro-chemical polymerized poly(3-hexylthiophene)/gold nanoparticles composite layer were studied. It was shown that 3-(11-mercapto-1-undecanoxyl)thiophene played an important role in this system: thiol groups closely attached on the surface of the gold nanoparticles through Au-S bonds, while thiophene groups were involved in copolymerization. Therefore, the gold nanoparticles are stabilized in the conducting polymer matrix with uniform diameters and dispersion. The device exhibits good electrical bistability with the on/off ratio of 104.