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.

控制液滴与表面相互作用的能力是一个广泛的科学利益的话题，并且具有许多实际应用。从用于建筑外墙或家用电器的自我清洁表面，到医疗应用和自我诊断，可以越来越多地呼吁能够完成无数任务的智能材料。最近，基于莲花叶的效应，人们对仿生系统（例如超疏水表面）的兴趣越来越大，最近，基于尼彭瑟斯·普斯特植物（Nepenthes Pitcher Pitcher）植物，最近对湿滑液体注入的多孔表面（SLIP）（SLIPS）引起了人们的兴趣。这种表面一直是它们在水分脱水和抗冰的能力方面引起人们浓厚兴趣的主题，以及它们在诸如涂料和喷墨印刷等应用中控制润湿的能力。当在显微镜上处理液体时，液滴的表面积与体积的比率变得更大，并且在运动过程中必须越来越大。为了诱导液滴在表面上的运动，还必须克服由于接触角滞后的静态摩擦力。当一条小滴坐在滑板上时，它在其底座周围显示了一个润湿山脊。这种润湿脊是由于液滴的三相接触线处的力平衡所致。该山脊的形状通常是作为Neumman三角形绘制的，取决于所涉及的液体的性质。在2015年，与同事（Langmuir，31（43），2015年），我表明，润湿脊的高度围绕表面上的液滴的高度也取决于基础表面的性质和质地。我们使用这样的表面表明可以测量一个明显的接触角，对于无柄液滴，就像固体表面上的液滴相似，并表明这种明显的接触线是高度流动性的，而磁滞很少。由于滑动表面的润滑性质，放置在这样的表面上的液滴很容易移动或移动。随后，我发展了一个新想法，即如果一个人将梯度引入滑动表面的基础地形，则可以在液滴中产生自主运动。此项目将产生表面，从而产生低接触角滞后，低摩擦力，并且能够将液滴施加到液滴上而无需任何抽水机制。我将在基础表面纹理的粗糙度以及注入液体润滑剂的粗糙度中使用梯度来创建梯度湿滑的液体注入的多孔表面（G-SLIPS）。我将使用滑动表面的这种变化，并由初步实验产生，以对此类表面的运动机理进行完整的研究。我将通过实验检查如何润滑液体或基础表面形貌等参数产生和控制液滴运动。最后，我将创建和测试能够与特定的微流体任务相称的规定运动的特定表面。该项目最终将为未来的无泵微流体系统的未来开发增添新技术，并创建克服接触线固定并使用滑动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.