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

  s-layer

   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

  Phase separation
 

    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.

  Boundary layer kinetics
    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

   polyelectrolyte

    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

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.

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