Recently, I have attended 141th European Study Group with Industry (ESGI) conference in Dublin. It is a very different type of conference/workshop than what I have been attending so far. First of all everything is free, including food, coffee, snacks accommodation and registration – thanks to funding bodies SFI, UCD, MI-NET, MACSI. Second, it is a great opportunity to meet experts from different fields. Third, there are not so many talks or hurried people and most people are young post graduates and post-docs rather than professors. Everyone is there to learn rather than to advertise their work. More importantly, everything ran smoothly till the end of the conference.
The theme of the conference is that industries across Europe pose 5-6 challenges and 50-100 researchers from EU will solve these challenges in 5 days. It is something like a hackathon. This year, most of the problems from the industry are data science related. Since data science/machine learning is a hot topic, many people opted for these challenges. I opted for a Physics related challenge, that is related to wetting/wicking of rough surfaces. A semiconductor company has been looking for an optimised rough surface that can be wetted as easily as possible.
Although it seems simple at first glance, it is important to stress that by roughing a surface, wetting can be enhanced many orders of magnitude. For example, if we leave a water drop on a flat surface it takes up to 10 days to spread a diameter of 2cm. While using a optimised rough surface it takes only 10s. Such fast wetting of surfaces has applications in biomedical sensors where for example blood or urine samples can be reached to sensing regions easily.
This problem is interesting as it brought me back into the basics of physics, mainly fluid dynamics. Along with me, there are 13 members who liked this Physics challenge. So we formed as team that consists of 2 professors from Oxford. In the end only 5-6 people remained interested in the project and the rest slowly drifted away. Within our team, we formed sub teams, according to the level of expertise. I worked on my own as I don’t have any particular expertise in fluid dynamics.
Problems were given before we were going to the conference, so I did some back ground reading. In the first day itself, I met the company representative from the semiconductor company who gave this challenge. I expressed my interest to him. I read as many as 20 papers on this topic and came to a conclusion that the most of the things that the company would like to know about wetting of a rough surface were already studied/solved.
So I took the second day completely to read more literature and to make sense of it. On the third day, I narrowed down on 5-6 good papers and analysed them deeply. According to these papers, my conclusions are as following:
1) Critical angle of a drop on a rough surface depends on the roughness and it will be different than the critical angle on a flat surface.
2) The roughness dictates whether a surface can be superhydrophilc or superhydrophobic
3) Most rough surfaces studies are silicon cylindrical pillars on silicon substrate.
4) Dynamics of liquid spreading on a superhydrophilic rough surfaces follows washburn’s law i.e. the penetration length of the liquid front is proportional to the square root of time.
5) One can optimise the geometrical parameters such as height and diameters of the pillars and periodicity between the pillars to achieve faster spreading of a liquid drop on a rough surface.
Overall, we presented our findings. I made some friends. I enjoyed dwelling into other scientific field. I hope these type informal conferences will happen more frequently. I highly recommend my fellow researchers to attend the future ESGI conferences. I am looking forward to attend the next ESGI workshop.
Ishino, C., Reyssat, M., Reyssat, E., Okumura, K., & Quéré, D. (2007). Wicking within forests of micropillars. Epl, 79(5), 6–11.