Self-Propelled Droplet Motion on Gradient Slippery Liquid Infused Porous Surfaces (G-SLIPS)

梯度光滑液体注入多孔表面上的自推进液滴运动 (G-SLIPS)

• 批准号: EP/P026613/1
• 负责人: Gary Wells
• 金额: $ 12.62万
• 依托单位: Northumbria University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2017
• 资助国家: 英国
• 起止时间: 2017 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FP026613%2F1
• 关键词: Self; Propelled; Droplet; Motion; Gradient

The ability to control how liquid droplets interact with surfaces is a topic of wide scientific interests and has many practical applications. From self-cleaning surfaces for building facades or domestic appliances, right through to medical applications and self-diagnostics, there is an increasing and invaluable call for smart materials capable of a myriad of tasks. Recently there has been an increasing interest in biomimetic systems such as super hydrophobic surfaces based on the Lotus leaf effect, and more recently on Slippery Liquid Infused Porous Surfaces (SLIPS) based on the nepenthes pitcher plant. Such surfaces have been the subject of much interest in terms of their capabilities for water shedding and anti-icing properties as well as their ability to control wetting in applications such as coating and inkjet printing.When dealing with liquids on a microscale, the ratio of a droplet's surface area to volume becomes ever larger and frictional forces must be overcome during motion. To induce motion of droplets on a surface, static frictional forces, due to contact angle hysteresis, must also be overcome. When a sessile droplet sits on a SLIPS it exhibits a wetting ridge around its base. This wetting ridge is due to the balance of forces at the three phase contact line of the droplet. Usually drawn as a Neumman Triangle, the shape of this ridge is dependent on the properties of the liquids involved. In 2015, with co-workers, (Langmuir, 31(43), 2015) I showed that the height of the wetting ridge around a droplet on a surface is also dependent on the nature and texture of the underlying surface. We used such a surface to show that one can measure an apparent contact angle, for a sessile droplet, much like that of a droplet on a solid surface and showed that this apparent contact line is highly mobile with very little hysteresis. A droplet placed on such a surface can move or be moved very easily because of the lubricating nature of SLIP surface. Subsequently I have developed the new idea that, if one introduces a gradient into the underlying topography of the SLIP surface, it is possible to generate autonomous motion in a droplet.This project will create surfaces which give low contact angle hysteresis, low friction and are capable of imparting motion onto droplets without the need for any pumping mechanism. I will use gradients in the roughness of an underlying surface texture, along with an infused liquid lubricant to create a Gradient Slippery Liquid Infused Porous Surface (G-SLIPS). I will use this variation of a SLIP surface and results from preliminary experiments to perform a full study into the mechanisms of motion on such surfaces. I will experimentally examine how parameters such as the type of lubricating liquid or the underlying surface topography create and control droplet motion. Finally, I will create and test specific surfaces capable of prescribed motion commensurate with specific microfluidic tasks. This project will ultimately add new techniques to the future development of pump free microfluidic systems and create surfaces that overcome both contact-line pinning and reduce viscous friction using SLIP Surfaces.

控制液滴如何与表面相互作用的能力是一个具有广泛科学兴趣的主题，并具有许多实际应用。从建筑外墙或家用电器的自清洁表面，到医疗应用和自我诊断，人们越来越多地要求能够完成各种任务的智能材料。最近，人们对仿生系统的兴趣越来越大，例如基于荷叶效应的超疏水表面，以及最近基于猪笼草猪笼草的滑动液体注入多孔表面（SLIPS）。这种表面由于其具有水脱落和防冰性能，以及在涂层和喷墨打印等应用中控制润湿的能力而备受关注。当在微尺度上处理液体时，液滴的表面积与体积的比率变得越来越大，并且在运动过程中必须克服摩擦力。为了引起液滴在表面上的运动，还必须克服由于接触角滞后引起的静摩擦力。当固着液滴位于SLIPS上时，它在其底部周围表现出润湿脊。该润湿脊是由于液滴的三相接触线处的力的平衡。通常被画成纽曼三角形，这个脊的形状取决于所涉及的液体的性质。在2015年，与同事，（朗缪尔，31（43），2015）我表明，表面上液滴周围的润湿脊的高度也取决于底层表面的性质和纹理。我们使用这样的表面来表明，可以测量表观接触角，对于固着液滴，很像固体表面上的液滴，并表明这种表观接触线是高度移动的，具有非常小的滞后。由于SLIP表面的润滑性质，放置在这种表面上的液滴可以非常容易地移动或被移动。随后，我开发了一个新的想法，即如果在SLIP表面的底层地形中引入梯度，就有可能在液滴中产生自主运动。该项目将创建具有低接触角滞后，低摩擦力的表面，并且能够在不需要任何泵送机制的情况下将运动传递到液滴上。我将在底层表面纹理的粗糙度中使用梯度，沿着注入液体润滑剂来创建梯度滑动液体注入多孔表面（G-SLIPS）。我将使用这种变化的滑移面和初步实验的结果进行全面的研究，这种表面上的运动机制。我将通过实验研究润滑液类型或底层表面形貌等参数如何创建和控制液滴运动。最后，我将创建和测试能够与特定微流体任务相称的指定运动的特定表面。该项目最终将为无泵微流体系统的未来发展增加新技术，并创建克服接触线钉扎和使用SLIP表面减少粘性摩擦的表面。

项目成果

Bidirectional motion of droplets on gradient liquid infused surfaces

• DOI: 10.1038/s42005-020-00429-8
• 发表时间: 2020-09-21
• 期刊: COMMUNICATIONS PHYSICS
• 影响因子: 5.5
• 作者: Sadullah, Muhammad Subkhi;Launay, Gaby;Kusumaatmaja, Halim
• 通讯作者: Kusumaatmaja, Halim

The long cross-over dynamics of capillary imbibition

• DOI: 10.1017/jfm.2022.248
• 发表时间: 2022-03
• 期刊: Journal of Fluid Mechanics
• 影响因子: 3.7
• 作者: É. Ruiz-Gutiérrez;S. Armstrong;Simon Leveque;C. Michel;I. Pagonabarraga;G. Wells;A. Hernández-Machado;R. Ledesma‐Aguilar

Self-propelled droplet transport on shaped-liquid surfaces

• DOI: 10.1038/s41598-020-70988-x
• 发表时间: 2020-09-11
• 期刊: SCIENTIFIC REPORTS
• 影响因子: 4.6
• 作者: Launay, Gaby;Sadullah, Muhammad Subkhi;Wells, Gary G.
• 通讯作者: Wells, Gary G.