Biological vesicles exhibit a variety of shapes as a function of the osmotic pressure difference and the membrane semiflexibility. There occurs distinct classes of shapes separated by continuous phase transition. This problem has been the topic of much study over the past couple of decades. My research for my Ph.D. thesis has been concentrated on understanding the full features of the two-dimensional vesicle problem. We have investigated both self-intersecting and self-avoiding classes of vesicles through a variety of analytic and numerical problems.
Mithun Kumar Mitra
Postdoctoral Associate
Polymer Science and Engineering
University of Massachusetts
Amherst, MA 01003
USA
Ph. : +1-413-577-2242
mithun .at. polysci.umass.edu
My research interests are in Soft condensed matter physics, Statistical mechanics and the physics of biological sytems. A complete list of my publications can be found here.
My full academic C.V. can be found here (PDF format).
Self-assembly of complex polymers
We have studied the self-assembly of proteins into ordered macroscopic structures, focusing in particular on S-Layer proteins, which are a naturally occuring example of a robust self-assembling system. We have developed a hierarchical modeling method using structural information from experiments to understand the molecular mechanisms of assembly in this system.
Kinetics of crystallization
Motivated by experiments on a system of a
two-component polyolefin blend, we worked out a theory for
heterogeneous nucleation in a binary system where two-first order phase
transitions are coupled together, a liquid-liquid phase separation of
the two components, and the simultaneous crystallization of one of the
components. Our theory explains the apparent deviations from ordinary
nucleation theory observed in the experiments, and provides new
predictions for further experiments.
We have worked out the long time growth kinetics for
a first order phase transition when there exists a free energy barrier
ahead of the growth front. This scenario is motivated by considering
the crystallization of long entangled polymer chains, where the
entanglements provide an entropic barrier. We find that in such a
scenario, the usual Lifshitz-Slyozov-Wagner growth law for average size
of the
nuclei,
<R(t)>
~
t1/3 is replaced by a new growth law,
<R(t)> ~ t1/2.
Polyelectrolyte Physics
We are currently working on theories for polyelectrolyte systems. Polyelectrolyte are charged polymers where the degree of ionization, or effective charge is coupled to the size (radius of gyration) of the polymers. Some of the systems we consider include :
- Single polyelectrolyte chain
- Polyelectrolyte solutions
- Polyelectrolyte gels
- Polyelectrolyte brushes
Phase transition in two dimensional vesicles
Microscopic model for microtubules
For my Masters thesis, we proposed and studied a structural model for microtubules. Microtubules, which are cylindrical structures found inside the cell, provide structural support and help in transport and cell division. They exhibit a phenomenon called dynamical instability in which the length of the microtubule oscillates rapidly through polymerization and depolymerization of the constituent tubulin dimers. We attempt to understand this phenomenon through a structural cap model.
| Publications | ||
| 1. |
Jing
Hua, Mithun K. Mitra, M. Muthukumar |
|
| ``Theory of gel volume transitions with self-regularization of charge'' | ||
| To be submitted to J. Chem. Phys. |
||
| 2. | Mithun K. Mitra, Gautam I. Menon, R. Rajesh | |
| ``Thermodynamic Behaviour of Two-dimensional Vesicles Revisited'' | ||
| To be submitted to Europhys. Lett. |
||
| 3. |
Christine Horejs, Mithun K.
Mitra, Dietmar Pum, Uwe B. Sleytr, M. Muthukumar |
|
| ``Monte
Carlo study of the molecular mechanisms of S-Layer protein
self-assembly'' |
||
| Submitted to J. Chem. Phys. | ||
| 4. |
Mithun K. Mitra, M. Muthukumar |
|
| ``Long-time
growth kinetics of a first order phase transition in the presence of a
boundary layer'' |
||
| Accepted for publication in J. Chem. Phys. |
||
| 5. |
Mithun K. Mitra, Gautam I.
Menon, R. Rajesh |
|
| ``Asymptotic
behaviour of convex and column-convex lattice polygons with fixed area
and varying perimeter'' |
||
| J. Stat. Mech. 2010, P07029 (2010) [arXiv:1003.2908 ] |
||
| 6. |
Mithun K. Mitra, M. Muthukumar |
|
| ``Theory
of spinodal decomposition assisted crystallization in binary mixtures'' |
||
| J. Chem. Phys. 132, 184908 (2010) |
||
| 7. | Mithun K. Mitra, Gautam I. Menon, R. Rajesh | |
| ``Asymptotic Behavior of Inflated Lattice Polygons'' | ||
| J. Stat. Phys. 131, 393 (2008) [arXiv:0710.1509] |
||
| 3. | Mithun K. Mitra, Gautam I. Menon, R. Rajesh | |
| ``Phase Transitions in Pressurised Semiflexible Polymer Rings'' | ||
| Physical Review E 77, 041802 (2008) [arXiv:0708.3318] |
||
References
| 1. | Dr. Murugappan Muthukumar |
| Wilmer D. Barrett Professor |
|
| Polymer Science and Engineering |
|
| University of Massachusetts |
|
| Amherst, MA 01003. |
|
| muthu@polysci.umass.edu |
|
| 2. | Dr. Gautam I. Menon |
| Professor, | |
| The Institute of Mathematical Sciences, | |
| C.I.T. Campus, Tharamani | |
| Chennai - 600113, India. | |
| menon@imsc.res.in |
|
| 3. | Dr. Rajesh Ravindran |
| Reader, | |
| The Institute of Mathematical Sciences, | |
| C.I.T. Campus, Tharamani | |
| Chennai - 600113, India. | |
| rrajesh@imsc.res.in |
|
| 4. | Dr. Buddhapriya Chakrabarti |
| Lecturer, |
|
| Department of Mathematical Sciences |
|
| Durham University |
|
| Durham DH1 3HP, UK. |
|
| buddhapriya.chakrabarti@durham.ac.uk |
|
| 5. | Dr. Sitabhra Sinha |
| Professor, |
|
| The Institute of Mathematical Sciences, | |
| C.I.T. Campus, Tharamani | |
| Chennai - 600113, India. | |
| sitabhra@imsc.res.in |