二氧化钒基驱动器的制备与优化

软体机器人是一类具有结构柔顺度高、环境适应性好、功能类型多样等特点的新型机器人，在康复、探测和救援等领域都具有广阔的应用前景。其中，驱动器作为软体机器人的核心执行部件，决定其性能与工作模式。高性能柔性驱动器的研究已经成为软体机器人领域的重点方向。

二氧化钒（VO₂）由于其近室温金属–绝缘体相变特性，成为制备高性能驱动器的理想智能材料。然而，目前报道的VO₂基驱动器局限于亚毫米量级，无法满足宏观软体机器人的应用需求。基于这一问题，本论文开展基于二氧化钒纳米线阵列（VO₂ nanowire array, VO₂ NA）驱动器的研究，主要工作简述如下。

我们开发了一种竖直VO₂ NA的水热制备策略，利用三氧化二锑（Sb₂O₃）提升成核位点，在石英衬底上低温制备了晶圆尺寸且竖直取向的VO₂ NA。本工作有效地调控了阵列密度以及纳米线长度，并阐释了VO₂ NA的生长机制。同时， VO₂ NA与衬底之间较弱的相互作用，使得VO₂ NA的转移更加容易，为实现NA薄膜的宏观器件应用奠定了基础。

我们还开发了一种水热结合退火工艺的策略，制造出水平超顺排VO₂ NA薄膜/碳纳米管（Carbon nanotube, CNT）双晶片薄膜驱动器，实现了软体机器人的基本功能。VO₂ NA/CNT驱动器展现了与传统VO₂微驱动器相似的驱动性能：对多种刺激响应，高的响应频率和长的使用寿命。此外，该驱动器还具有优异的各向异性与可加工性，通过激光切割实现了多种仿生机器人的制造，如仿生尺蠖、飞行翼、扭转机器人等。这一工作实现了将VO₂优异的驱动性能应用在宏观器件上的基本目标，也为开发高性能软体机器人提供了新的思路。

The soft robot is a new kind of robot with high structural flexibility, good environmental adaptability, and diverse functions. It has a broad application prospect in the fields of rehabilitation, detection, and rescue. Actuator as the core executive component of soft robot, directly determines its performance and working mode. Therefore, high-performance flexible actuators have become the focus of research.

Vanadium dioxide (VO₂) is an ideal smart material for the preparation of high-performance actuators because of its metal-insulator phase transition near room temperature. However, the currently reported VO₂-based actuators are still limited to the sub-millimeter scale and cannot meet the application requirements of macroscopic soft robots. Based on this issue, this thesis focuses on the preparation and optimization of vanadium dioxide nanowire array (VO₂ NA) based actuators. The main work is briefly described as follows.

We develop a preparation strategy for growing vertical VO₂ NA by hydrothermal method by effectively enhancing the nucleation sites of VO₂ crystals. VO₂ NA can be prepared at low temperature with adjustable wafer size and vertical alignment. This work effectively controls the array density and nanowire length and explains the growth mechanism of VO₂ NA. Besides, the weaker interaction between the prepared VO₂ NA and substrate makes the transfer of NA film easier, laying a foundation for its application in macroscopic devices.

We also develop a preparation strategy combing hydrothermal method with annealing process to prepare horizontal super-aligned VO₂ NA films, which is further laminated with carbon nanotube (CNT) films to form centimeter-sized bimorph actuators, which realizes the basic functions of soft robots. The VO₂ NA/CNT actuator prepared in this work shows similar actuation performance to the traditional VO₂ micro actuator, such as high amplitude, high output work density and working modes in response to a variety of stimuli as well as fast response frequency and long working life. In addition, this work also shows the excellent anisotropy and machinability of actuators. The effective modulation of device shape and working mode of actuators can be realized by laser cutting. A variety of bionic applications are demonstrated, such as bionic inchworm, flying wing, torsion robot and so on. This work not only realizes the basic goal of applying the excellent actuation performance of VO₂ to macro actuators, but also provides a new idea for the development of high-performance soft robots.

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