Composite fiber as well as preparation method and application thereof

Abstract

The invention discloses composite fiber as well as a preparation method and application thereof. The composite fiber comprises conductive fiber and a nanofiber sheath layer coating the surface of the conductive fiber, wherein the nanofiber sheath layer comprises a three-dimensional porous structure formed by interweaving polymer nanofibers, and the three-dimensional porous structure is filled with ionic liquid. The ionic liquid adopted by artificial muscle fiber provided by the invention is room-temperature molten salt, is low in vapor pressure, not easy to volatilize and wide in electrochemical window, is less affected by solvent evaporation compared with an organic or inorganic electrolyte used at present, and can stably work in air; and an electrolyte layer is formed by adopting an ionic liquid-filled nanofiber network, so that the use stability of the electrochemical artificial muscle fiber in the air can be ensured, and the service life is greatly prolonged.

Description

technical field [0001] The invention relates to an artificial muscle fiber, in particular to a composite fiber and its preparation method and application, belonging to the technical field of material science. Background technique [0002] Similar to biological muscles, artificial muscles have the characteristics of large contractile stress, high power density and high energy density, and have the characteristics of weaving and integration. In recent years, they have received extensive attention in the field of mechanical exoskeletons and soft robots. In many artificial muscles Among them, electrochemical artificial muscles have attracted widespread interest due to their low operating voltage, no obvious thermal effect, and no limitation of Carnot efficiency. [0003] Foroughi et al. first reported the twisted multi-walled carbon nanotube artificial muscle, which can produce 1 when stimulated at a voltage of 5V (vs. % shrinkage, by continuing to increase the fiber twist to f...

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Problems solved by technology

[0004]However, the liquid working system severely limits the practical application of the above-mentioned electrochemical artificial muscles. In order to meet the challenge of the liquid working system, some current work has reported gel type electrolyte system, the quasi-solid artificial muscle prepared by using this electrolyte system is usually composed of two fibers serving as positive and negative electrodes; Lee et al. > The CNT artificial muscle with aqueous solution-poly(vinyl alcohol) gel electrolyte produced a contraction of 0.52% when driven at 1V; while the use of organic gel electrolyte can make the artificial muscle work at a higher driving voltage, at 5V driving voltage The parallel and braided CNT fibers can obtain high shrinkage of 11.6% and 5%. Due to the low mechanical strength and poor dimensional stability of these gels, it is easy to short circuit between the two electrodes. In order to avoid the short circuit phenomenon, between the two electrodes A certain distance must be kept between them, but this increases the impedance of ion transport. In addition, the evaporation of solvents in the gel electrolyte will limit the long-term working stability of electrochemical artificial muscles.

[0005] In summary, the existing technology mainly has the following disadvantages: 1) The volume and weight of the liquid electrolyte system are large, 2) The liquid working system severely limits its application in smart wearables. 3) Viscous gel has poor structural stability and dimensional stability, and is easy to short circuit. 4) Currently used electrolytes are facing problems such as solvent evaporation and cannot work stably in the air for a long time

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