Prof. Rabibrata Mukherjee's Talk

Mar 18, 2016 - 11:00

Mar 18, 2016 - 12:00

Room 240 Chemical Engineering

Seminars

Prof. Rabibrata Mukherjee Department of Chemical Engineering IIT Kharagpur

Abstract: Ultra thin films tend to become unstable due to amplification of disjoining forces on a non wettable substrate leading to its spontaneous rupture and dewetting. This offers a novel route for the fabrication of nano and meso scale patterns. The limitation however is such instability patterns are random and isotropic. We have been exploring possibilities of aligning these instability patterns by laterally confining the evolution pathway on a topographically patterned substrate. We have looked into the fundamental issue related to the morphology of an as cast film on a topographically patterned substrate and observed that depending on the wettability of the substrate by the casting solvent a continuous film forms only above a critical solution concentration (ACS AMI 2012). In fact it is possible to obtain extremely well ordered structures for lower concentrations. We have extended this concept to obtain a novel alternate polymer droplet array (Nano Letters 2014). I may also highlight some of our recent work on the dewetting of a thin polymer bilayer on a topographically patterned substrate that leads to extremely complex well ordered structures (Macromolecules 2013; Nanoscale 2016). We will also discuss how utilizing the essential concepts of Soft Lithography and Stress Relaxation we could come up with a novel nano patterning technique that allows fabrication of patterns with different feature height from a single stamp (ACS Macro Lett. 2013). We extended this approach for fabricating a topography gradient surface (ACS AMI 2014) that allowed us to perform various combinatorial dewetting studies (ACS AMI 2012). We are presently engaged in developing a method that allows fabrication of tall nano structures from a shallow stamp based on the concept of bonding debonding hysteresis observed in contact instability of thin soft elastic films. Key References: 1. S. Roy K. J. Ansari S. S. K. Jampa P. Vutuluri and R. Mukherjee ACS Applied Mater Interfaces 4 1887 2012. 2. S. Roy and R. Mukherjee ACS Applied Mater Interfaces 4 5375 2012. 3. S. Roy D. Biswas N. Salunke A. Das P. Vutukuri R Singh and R. Mukherjee Macromolecules 46 935 2013. 4. N. Bhandaru S. Roy Suruchi G. Harikrishnan and R. Mukherjee ACS Macro Letters 2 195 2013. 5. S. Roy N. Bhandaru R. Das G. Harikrishnan and R. Mukherjee ACS Appl. Mater. Interfaces. 6 6579 2014. 6. N. Bhandaru A. Das N. Salunke and R. Mukherjee Nano Letters 14 7009 2014. 7. N. Bhandaru A. Das and R. Mukherjee. Nanoscale 8 1073 2016.About the speaker: Dr Rabibrata Mukherjee obtained his PhD from IIT Kanpur in 2007 under the supervision of Prof Ashutosh Sharma. He is presently an Associate Professor of Chemical Engineering at IIT Kharagpur where he joined as in 2009 as an Assistant Professor. Prior to this he was a Scientist at CSIR – Central Glass & Ceramic Research Institute (CGCRI) Kolkata between 1997 and 2009. His research area includes thin film instability dewetting soft lithography colloidal self-assembly structural super hydrophobicity Electro-hydrodynamic instability etc. He has published 35 research papers in international journals which includes journals like Nano Letters ACS Nano Advanced Materials Advanced functional Materials Macromolecules Langmuir Soft Matter ACS Applied Materials & Interfaces etc. He received the CSIR Young Scientist award in 2007 and the MRSI medal in 2014. He obtained the highest teaching feedback in IIT Kharagpur in the Spring Semester 2015 for his course “Instability and Patterning of thin Polymer Films”.