Research on Response Regulation of Pressure-driven Multi-droplet Wetting State
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摘要: 液液界面浸润性可控操作的实现，在界面纳米有序结构组装、液体透镜调节、航空航天等方面具有重要意义。从宏观尺度研究了以表面活性剂溶液为底液的液液界面浸润问题，进行以表面活性剂溶液为底液、正十六烷为操控对象的浸润可控调节研究，分析界面单层活性剂分子在液体动态浸润性变化过程中的内在机理，选择固定浓度的表面活性剂溶液，以此匹配最佳的正十六烷铺展状态。通过拉压驱动液面的方式改变液滴铺展状态：挡板拉伸时，每个液滴浸润面积增大，并产生液滴形变；挡板压缩后，浸润面积减小，恢复圆环形状。实现了浸润状态的动态响应。通过拉压，实现了对单液滴的铺展–收缩的控制，在单液滴的基础上实现了双液滴、三液滴浸润状态的协同。Abstract: The liquid-liquid interface spreading engineering has a wide range of applications. Surfaces with controllable wettability can be stimulated to realize the modulation of the wettability state, which is of great importance in nanofluidics, medical field, and materials science. The motion of the three-phase contact line has self-similarity, and the spreading radius and the spreading time are proportional to the power exponential relationship of R~tn and the dynamic mechanism of spreading during infiltration can be reflected through the power index n. In this paper, the liquid-liquid interface wetting problem with surfactant solution as the substrate is investigated on a macroscopic scale, and the intrinsic mechanism of the interfacial monolayer of active agent molecules in the process of changing the dynamic wettability of the liquid is analyzed. The wetting experimental system composed of n-hexadecane as the driven droplet and sodium dodecyl sulfate solution as the base solution was established by changing the droplet spreading state by pulling pressure to drive the liquid surface, and the dynamic response of the wetting state was realized. On the basis of single droplet, the synergistic wetting state of double droplet and triple droplet was realized. The work of this paper gives new ideas and means for liquid interface manipulation, which is expected to be applied in interface assembly technology.
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Key words:
- Liquid-liquid interface /
- Surfactant /
- Interface control /
- Multiple droplet deformation
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图 2 两挡板拉–压双液滴实验过程。（a）～（c）为拉伸过程；（c）～（e）为压缩过程
Figure 2. Experimental process diagram of two baffle pull-pressure double droplets. (a)～(c) Stretching process, (c)～(e) compression process
图 3 双液滴拉压周期实验铺展直径与挡板间距随时间的变化
Figure 3. Double droplet pull-compression cycle experiment with spread diameter and baffle spacing over time
图 4 双液滴拉伸过程液滴直径与时间的标度关系
Figure 4. Relationship between droplet diameter and time scale in double droplet drawing process
图 5 三液滴不同速度拉压实验过程。（a）～（c）为拉伸过程，（c）～（e）为压缩过程
Figure 5. Experimental process diagram of three droplets with different speed tensions and compressions. (a)～(c) stretching process, (c)～(e) compression process
图 6 三液滴拉压过程液滴直径与挡板间距随时间的变化关系
Figure 6. Relationship between droplet diameter and baffle spacing in the process of droplet pulling and compression
图 7 三液滴拉伸过程液滴直径与时间标度关系（D1为与挡板运动方向平行直径，D2为与挡板运动方向垂直直径）
Figure 7. Relationships between droplet diameter and time scale in three-droplet drawing processes (D1 is the diameter parallel to the direction of baffle movement, D2 is the diameter perpendicular to the direction of baffle movement)
图 8 三液滴拉压实验中间液滴直径与时间的标度关系
Figure 8. Relationship between droplet diameter and time scale in the three-droplet pull-pressure experiment
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