Department of Physics

Indian Institute Of Technology Madras , Chennai

Tuning Properties of Nanoconfined Polymers

Speaker : Dr.Mithun Chowdhury, Chemical & Biological Engineering, Princeton University, USA

2017-08-18

Abstract :

In this talk, I will discuss two important themes in contemporary polymer science: nanoscale confinement effects on polymer properties and new routes of processing nanoscale polymer thin films exploiting confinement.Concerning the former, significant effort has been devoted to pursing an understanding of the glass transition temperature of polymers confined to the nanoscale, mostly as films. At the same time a series of mechanorhelogical probing techniques have been developed, such as dewettingof polymers over a slippery substrate has been found to have role on the viscoelastic properties of the film. I will show how preparation induced stresses can be correlated to the non-equilibrium polymer chain conformations and surprisingly fast molecular mobilityoften used to explainglass transition in thin polymer films. Further, I will show our recently developed approach of probing layer resolved shear mobility and viscosity in thin polymer films that uses simple gas blowing. Then I will show how lessons learned from properties of thin polymer film confinement can be extended to the preparation of kinetically and thermodynamically stable polymer glasses such as byMatrix Assisted Pulsed Laser Evaporation (MAPLE) deposition. Finally, if time permits, I will show how such material fabrication approach could be extended towards controlling crystallinity in semi-crystalline polymers, which have consequences on the optoelectronic properties of conjugated polymers.

References:

1. Chowdhury, M., & Priestley, R. D. (2017). Discrete mobility on the surface of glasses.Proceedings of the National Academy of Sciences USA, 114(19), 4854-4856
2. Raegen, A., Chowdhury, M., Calers, C., Schmatulla, A., Steiner, U., & Reiter, G. (2010). Aging of thin polymer films cast from a near-theta solvent. Physical Review Letters, 105(22), 227801
3. Chowdhury, M., Freyberg, P., Ziebert, F., Yang, A. C. M., Steiner, U., & Reiter, G. (2012). Segmental relaxations have macroscopic consequences in glassy polymer films. Physical Review Letters, 109(13), 136102.
4. Chowdhury, M., Guo, Y., Wang, Y., Merling, W. L., Mangalara, J. H., Simmons, D. S., & Priestley, R. D. (2017). Spatially Distributed Rheological Properties in Confined Polymers by Noncontact Shear. The Journal of Physical Chemistry Letters, 8(6), 1229-1234.
5. Chowdhury, M., Al Akhrass, S., Ziebert, F., & Reiter, G. (2017). Relaxing nonequilibrated polymers in thin films at temperatures slightly above the glass transition. Journal of Polymer Science Part B: Polymer Physics, 55(6), 515-523.
6. Guo, Y., Morozov, A., Schneider, D., Chung, J. W., Zhang, C., Waldmann, M., ...& Priestley, R. D. (2012). Ultrastable nanostructured polymer glasses. Nature materials, 11(4), 337-343
7. Chowdhury, M., Sajjad, M. T., Savikhin, V., Hergué, N., Sutija, K. B., Oosterhout, S. D., ... & Samuel, I. D. (2017). Tuning crystalline ordering by annealing and additives to study its effect on exciton diffusion in a polyalkylthiophene copolymer. Physical Chemistry Chemical Physics, 19(19), 12441-12451

Key Speaker Dr.Mithun Chowdhury, Chemical & Biological Engineering, Princeton University, USA
Guests None
Place Seminar Room
Start Time 3:00 PM
Finish Time 4:00 PM
External Link None