LUBFLOW

Background:

A lubricant-infused surface (LIS) is a microstructured surface infused with a viscous liquid lubricant layer. These slippery surfaces are partially inspired by the carnivorous pitcher plant (genus Nepenthes). The plant traps its prey (such as ants) by luring them to the liquid-filled textured peristome, where they aquaplane into the pitcher to be digested. Our understanding of LIS in static "air-exposed" environments is relatively mature; they can be tuned to repel liquid droplets, inhibit icing and condensation and resist the attachment of microorganisms.

LISs have also been shown to have many functions submerged in flowing liquids. This includes resisting fouling, reducing flow drag, increasing heat transfer, adsorbing or releasing substances or providing means of actuation. However, all these functions have been demonstrated in ideal or gentle flow conditions. The behaviour of LISs in realistic flow environments that contain turbulence, surfactants and bacteria is very difficult to predict. Our inability to predict LIS is the main limitation that hinders the broad use of LIS in submerged conditions.

Objectives:

LUBFLOW is an ambitious project that aims to advance our understanding of lubricant-infused surfaces in harsh flow conditions that contain turbulence, surfactants, and bacteria. By exploring the rich physics of LIS, we aim to uncover new insights into how these surfaces can be used to control particles, facilitate thermocapillary pumping, and enable actuation in fluid flows. These new functions could have significant implications for a wide range of technological applications, from reducing drag and preventing biofouling to improving heat transfer and enhancing flow control.

Depending on your background and interests, by joining LUBFLOW, you can work on either experimental or computational fluid mechanics combined with chemistry, biology, or materials science.

LUBFLOW tasks focus on understanding different aspects of lubricant-infused surfaces:

- Interfacial phenomena of surfaces in laminar or turbulent flows

- Effects of surface tension variations caused by surfactants and thermocapillary

- Bacterial biofilms on interfaces in flows

-Efficient numerical solutions for interfacial turbulent flows

As a PhD student, you will have the opportunity to contribute to one or more of these topics based on your skills and interests.

Approach:

Our group at KTH specializes in discovering the physics of surfaces in flows, including the modification of flow slippage by surfactants, the development of biofilm patterns in flows, and the formation of complex lubricant patterns under turbulence.

We have developed specialized tools to study LIS, such as a direct numerical simulation code, minifluidic channels to investigate biofilm formation, and a long water channel to study LIS in turbulence. In LUBFLOW, we will integrate these computational and experimental tools to isolate mechanisms and gain a fundamental understanding of lubricant-infused surfaces in harsh flow conditions.

In addition, the work will take place in collaboration with some of the best research groups worldwide in the field and also provide team members with the opportunity for longer stays abroad in connection with such collaborations.

If you want to know more about LUBFLOW or are interested in joining the team, feel free to contact us.