【作者】 张晓洁；

【导师】 成梦娇；

【作者基本信息】 北京化工大学 ， 化学， 2021， 硕士

【摘要】 受天然材料或生物运动现象启发,人们发展了大量具有刺激响应特性的智能运动器件,并在定向液体输运、传感、生物医药和能量转换等前沿领域获得了广泛应用。东亚文化中的茶叶,源于自然,历经多种人为加工,在热水冲泡过程中经常呈现往复浮沉运动的奇妙现象,有望为智能运动器件的设计提供新思路。然而,目前尚无系统化阐释茶叶浮沉机制的研究,仿生茶叶运动的智能器件开发也相对匮乏。为此,本论文从茶叶的微观结构和表面润湿性角度,阐释了茶叶往复浮沉的机制,即快速浸润后束缚多孔结构中的气体,从而产生温度响应的密度变化,在具有温度梯度的环境中实现往复运动;受此启发设计并制备了能在垂直方向往复运动的热响应性智能器件,探索了其在能量转换方面的应用。创新性研究成果如下:1.通过表征茶叶微观结构、表面润湿性、动态润湿过程和运动过程温度监测等,证明了茶叶内部多级空腔结构和表面亲水性对于束缚气体的作用,阐释了茶叶在冲泡过程中的浮沉机制,即温差导致茶叶内部所束缚气体体积变化,引起茶叶整体密度发生周期性变化,从而实现茶叶往复浮沉。2.受茶叶往复浮沉机制启发,设计制备了具有空腔结构的热响应型智能器件,利用亲水性材料束缚气体,并在40℃温差环境中实现了器件的周期性密度变化和往复浮沉运动。将器件运动与法拉第电磁感应定律相结合,实现了器件动能向电能的转变,稳定输出电压达3 V,能量转换效率达0.52%。器件内部气体的快速热响应保证了运动的周期性和能量转换的稳定性。更多还原

【Abstract】 Inspired by natural materials or biological motion,many intelligent devices with stimulus response characteristics have been developed and widely used in the frontier fields such as directional liquid transport,sensing,biomedicine and energy conversion.Tea originated from nature,often presents a wonderful phenomenon of reciprocating surfacing and sinking motion in the process of infusion,which is expected to provide a novel way of spontaneous motion.However,there is no systematic study on the mechanism of tea surfacing and sinking.And the development of intelligent devices for bionic tea movement is relatively scarce.Therefore,this thesis explains the mechanism of tea reciprocating motion through the microstructure and wettability of tea.The gas in porous structure is bound after rapid infiltration,resulting in the density change of temperature response and realizing reciprocating motion in the environment with temperature gradient;Inspired by this,a thermal responsive smart device was designed and fabricated,and its application in energy conversion was explored.Innovative research results are as follows:1.By characterizing the microstructure,surface wettability,dynamic wetting process and temperature monitoring during reciprocating movement of tea,the effect of multi-level cavity structure in tea was proved.And the hydrophilic surface help hold the gas inside tea.The surfacing and sinking mechanism of tea in the process of infusion was explained.The temperature difference leads to the volume change of gas in tea,resulting in periodic changes in the overall density of tea,so as to realize the reciprocating surfacing and sinking.2.Inspired by the mechanism of tea reciprocating surfacing and sinking,a thermal response intelligent device with cavity structure was designed and prepared.The gas was bound inside the device by super-hydrophilic materials.The periodic density change and reciprocating motion of the device were realized in a temperature difference environment.By Combining the device motion with Faraday’s law of electromagnetic induction,the kinetic energy of device was transformed into electrical energy,and the stable output voltage was up to 3 V.In the process of energy conversion,the fast thermal response of internal gas ensures the periodicity of motion and the stability of energy conversion.更多还原