Fundamental investigations of carbon nanotubes working as actuators

First published in
Proceedings of SPIE 
Number in series
7978
Article Number
79780O
Citation
Proceedings of SPIE - The International Society for Optical Engineering 7978 (): 79780O (2011)
Contribution to Conference
Conference Behavior and Mechanics of Multifunctional Materials and Composites 2011 
Publisher DOI
10.1117/12.879838
Scopus ID
2-s2.0-79957871988
Publisher
SPIE
Excellent properties like low density, high mechanical stiffness as well as an outstanding thermal and electrical conductivity make researchers focusing on carbon nanotubes (CNTs) since years. Beside that it is found that structures made of CNTs can be actuated when they are set up like a capacitor. Usually two dimensional (2D) CNT-papers with randomly oriented CNTs, called Bucky-papers, are used. They are charged and divided by an electrically insulating but ionic conductible electrolyte. Experiments demonstrate low voltages for actuation (±1V). Although the mechanism of CNT-actuation is still an open issue theoretical studies suggest a charge and ion induced lengthening of the C-bonds, which predict theoretical strains up to 1%. These characteristics make CNTs a potential candidate for lightweight and powerful actuators of future adaptive aerospace applications. The presented work gives an overview of possible CNT-actuator configurations. Comprehensive analysis tools for 2D mats of randomly oriented CNTs have been developed to guarantee a consistent data base for the comparison of different CNT-configurations. It is focused on the electro-mechanical properties with respect to the processing and configuration of CNT-actuators. For a more efficient use of the mechanical advantages of the CNT-geometry a new aligning manufacturing approach is presented, to get highly oriented 2D CNT-papers. Their properties are compared with randomly oriented CNT-papers. Finally a new test set-up will be introduced, which enables deflection measurements directly on the top of vertically aligned CNTs (CNT-arrays). The buildup and necessary prework are shown, as well as results of the first experiments. The method of measuring along the axis of aligned CNTs qualifies this set-up to get a deeper understanding about the actuation mechanism of CNTs. Vertically aligned CNTs promise to be a more efficient actuator configuration because of their high stiffness in direction of actuation. © 2011 SPIE.
Schlagworte
Actuation mechanism
Actuator
Bucky-paper
Carbon nanotube
Liquid electrolyte
Solid electrolyte
DDC Class
530: Physik
600: Technik
620: Ingenieurwissenschaften