This paper reports novel electromechanical behavior for a natural biopolymer film due to the incorporation of a conductive carbon nanotube network. Through simple solution blending and casting, high weight fraction single-walled carbon nanotube-chitosan composite films were fabricated and exhibited electromechanical actuation properties with motion controlled by low alternating voltage stimuli in atmospheric conditions. Of particular interest and importance is that the displacement output imitated perfectly the electrical input signal in terms of frequency (<10 Hz) and waveform. Operational reliability was confirmed by stable vibration testing in air for more than 3000 cycles. Proposed electrothermal mechanism considering the alternating current-induced periodic thermal expansion and contraction of the composite film was discussed. The unique actuation performance of the carbon nanotube-biopolymer composite, coupled with ease of fabrication, low driven voltage, tunable vibration, reliable operation, and good biocompatibility, shows great possibility for implementation of dry actuators in artificial muscle and microsystems for biomimetic applications.

Carbon nanotubes (CNTs) have found many potential applications stemming from their small dimensions and marvellous electronic, mechanical, and thermal properties. One of the barriers for using CNTs as building blocks in nanoelectronics is the high contact resistance. This paper reviews recent progress on the research of contact resistance of CNTs. It starts with a preview of two basic contact configurations, i.e., side contact and end contact, and measurements of contact resistance. The formation of Schottky barrier on a typical metal-semiconductor contact is then presented, aiming at looking for ways to reduce contact resistance from a theoretical point of view. The current techniques for improving CNT contact resistance are classified and summarized as well. The principles and applicabilities of these techniques are compared and discussed. A deep understanding of the forming mechanisms and improvement methods of contact resistance is critical in order to bring CNT-based devices from laboratory to the real-world technology.

No abstract

In this review, we first briefly recapitulate the orientation characteristics of liquid crystalline carbon nanotubes (CNTs), emphasizing their inherent properties.