Mechanical properties of polymer/carbon nanotube composite micro-electromechanical systems bridges

作者：Sousa P M^*; Chu V; Conde J P

来源：Journal of Applied Physics, 2013, 113(13): 134508.

DOI：10.1063/1.4798577

Microelectromechanical systems with all-polymer structural layers are expected to allow novel MEMS applications due to their mechanical, optical, electronic, and chemical properties, which are tunable and distinct from the standard inorganic layers currently used. The mechanical properties of micro-electromechanical bridge resonators (pMEMS) based on a polymer/carbon-nanotubes (CNT) composite structural material are presented. The structural material of the electrostatically actuated pMEMS microresonators are multilayers of a conductive polymer based on poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) to which carboxylated multi-wall CNTs monolayers are electrostatically attached after surface functionalization. The effects of measurement pressure, temperature, and applied load on the resonance frequency and on the quality factor, Q, of the pMEMS are studied. The long term reliability of the pMEMS resonators is also investigated, and the resonators were subjected to above 10(11) actuation cycles without significant performance deterioration. The mechanical properties of the pMEMS are systematically compared to those of a doped hydrogenated amorphous silicon (n(+)-a-Si:H) MEMS. While the CNT multilayers increase the rigidity (and hence the resonance frequency) as well as the electrical conductivity of the structural layer, they decrease the energy dissipation (and hence increase Q). Changes in CNT-polymer matrix adhesion result in reversible changes of the resonator properties during operation, requiring monitoring and control.

• 出版日期2013-4-7