Micro Fluidics & Nano Patterning – Anirban Majumder

Anirban Majumder, Graduated from Department of Chemical Engineering, in 2020, PhD candidate at University of Pennsylvania

This micro specialization will allow the students to understand how the nature of fluid flow changes under severely confined conditions. The specialization will focus on how the effect of different forces changes/ get altered in the mesoscale, due to enhanced effect of surface tension, capillary forces as well as dispersion forces. The course will introduce to a student how scaling relations influence the transport properties at this length scale. Further, experimental investigation at this length scale also requires significant knowledge on micro and nanoscale fabrications. The specialization thus aims at covering the essential concepts of fluidics and microfabrication techniques, providing the students with advanced expertise and knowledge in this cutting edge area of research.

-Source: Brief Description of the micro specialization curricula

Q.1 In your curriculum, you had mandatory foundation courses Fluid Mechanics(ME60011) and Advanced Fluid Mechanics(CH61011) out of which you had to choose 1. Now ME60011 is quite disjunct from, but a lot broader than any other UG depth course on fluid mechanics(MA40011, PH20101, CH20001 and ME21101) and so is CH61011, but apart from few introductory topics, the 2 courses diverge towards completely different regimes. Former focuses mostly on the physical characterization of various phenomena and systems while the latter focuses for a good part on turbulence modelling(major area of interest for larger length scales) and fluidization techniques.

What was your thought process of choosing one of them?

Response: I chose the course Advanced Fluid Mechanics(CH61011) in my 7th sem, primarily because I thought it is being offered by my department so I will be better equipped to handle the course. But to be honest, I regretted choosing it. It was taught by 2 professors. The first half, till turbulence modelling etc. was taught in an absolutely brilliant way. But the second half, rheology and fluidization techniques were taught by another professor and not a single student, in my knowledge, understood the concepts properly. The class consisted of M.Tech and PhD students too. The problem was that a lot of prerequisites from mathematics and fluid mechanics were needed to understand those topics. Basics not being covered is the biggest void of the course. The other course Fluid Mechanics(ME60011) is self-complete and was taught brilliantly.

Q.2 The course that you chose in component-1, how exactly was it useful for the rest of your curriculum?

Response: I don’t think CH61011 was much relevant in the rest of the curriculum, though I enjoyed the first half of the course. I feel that instead of that course, Transport Phenomena should be there in Component-1, instead of being in Component-2. Because it is essential to understand courses like Microscale Energy Transport in component-2.

Q.3 In Component-2 you had Microfluidics, Transport Phenomena (Depth course for CH), Intro to NanoTech and Microscale Energy Transport, out of which you had to choose 2. Which subjects did you choose?

Response: I chose Microscale Energy Transport and Microfluidics.

Follow up: Now from the course content and the references suggested for this course(like some standard books on Quantum Mech, solid-state and semiconductor physics), it raises a doubt: Will it be quite hectic those undergrads who didn’t take any basic courses on QM like Physics-2 or Semiconductor Physics(EC21107)?

Response: No, none of the phenomena or techniques were taught in the quantum regime also the course was not that theoretical. Many useful concepts and techniques which are relevant in research and industry like electrokinetics, fabrication, patterning etc and results from very recent researches were taught. Many applications were also touched upon like microelectronics’ cooling etc.

Biomedical industry uses this field extensively. For example, a recent method to break the blood clots is to inject microbubbles in blood and combine it with ultrasound for the purpose. In the Electronics industry, companies like Intel have a separate department for chip cleaning which takes very intricate engineering to use special surfactants. And then in chip cooling, the fluid droplets are moved around the chip through the hot spots by electrically changing the wetting nature of the surface.

Follow up: So from the course content of Microfluidics, it apparently covers an extensive range of applications and techniques starting from the very basics. What are your views on this course?

Response: Most parts of this course were taught by Prof. Suman Chakraborty, who is internationally renowned and a leading researcher in the field of Microfluidics, currently also Dean, SRIC). Many techniques, applications and phenomena were backed up by his own research career which is potentially the greatest level of distinction a course can attain. The course covered the most fundamental physics to its applications in the biomedical industry. Prof. Aditya Bandhopadhyay also taught many topics and he used to do microfluidic computations live on Octave during that class and show us simulations and other results.
So basically the course covered a broad spectrum from fundamentals to applications to analysis.

Q.5 In component-3 you had only one course– Instability and Patterning of Thin Polymer Films. What would you say about this course? And despite the name, the course content shows that it focuses on nanopatterning of thin films in general but not Thin Polymer Films. How true is that?

Response: The course covers all the topics which are covered in the module-4 of the course Intro to Nanotech like lithography, wetting dynamics etc. and the advancement of those topics and techniques. Some Nobel Prize-winning works of Pierre-Gilles de Gennes on Soft Matter are also taught in this course. And I think the course is a bit misnamed because the course only briefly touches upon concepts specific to polymers.

Q.6 How strongly would you recommend it to students from those branches other than CH, ME, PH, MT or CY?

Response: This is an interdisciplinary field so of course, there is scope for people working in the electronics or biotech domain as well but they will have to do a lot of extra work to handle the curriculum. For example, Transport Phenomena was a depth course for me, so it helped and so did the 2nd year fluid mechanics course. But that may not be the condition for all the branches.

Q.7 What is your current field of interest and how is the micro-curricula going to help you?

Response: The guiding professor and project haven’t been allotted yet to me in the University of Pennsylvania, that is scheduled in October, but my current interests where I would like to proceed are in microfluidics, soft-matter and later on, I want to enter into biomedical research.