 |
 |
||||||||||
|
|||||||||||
research topics
research
Polymer Solutions
Over the past few years, a revolution has occurred in the understanding
of the rheological behaviour of polymer solutions on experimental, theoretical
and computational fronts. On the experimental front, two advances are
notable: First, the development of the filament stretching rheometer by
T. Sridhar at Monash University, which is capable of generating a uniform
flow field in which polymer molecules can be unravelled from their coiled
state into extended structures, and in which the stresses that are produced
in the process can be measured simultaneously; and second, the introduction
by Chu and co-workers of a protocol for the measurement of certain microscopic
quantities in flowing solutions of fluorescently tagged DNA molecules.
The notable theoretical advance is the development of molecular theories
by the our group and others, which are centered on a greater understanding
of the role that the solvent plays in determining the dynamics of the
polymer molecule, as a result of which, all the important microscopic
phenomena that are responsible for the macroscopic response of a polymer
solution can be taken into account. Last but not least, the computational
advance is the development of Brownian dynamics simulation algorithms
with which exact solutions to the basic equations of these sophisticated
molecular theories may be obtained.
These three developments have enabled
the nearly quantitative description of the rheology of polymer solutions.
In particular, while until relatively recently, the validation of statistical
theories of polymer solution dynamics has largely been confined to the
comparison of predictions with experiments of macroscopic observables,
such as linear viscoelastic properties, and the dependence of shear and
elongational viscosities on flow strength, the experiments of Chu and
co-workers, in which perhaps the first direct measurement of a microscopic
quantity that is characteristic of a dilute polymer solution undergoing
flow was made, have raised the issue of model validation to a new level.
The central aims of our research are, (i) to establish an experimental
program that will compile a set of internally consistent data, which is
currently nonexistent, using the sophisticated experimental techniques
and expertise available at Monash University and with our collaborators,
that is sufficiently large for a rigorous investigation of all features
of dilute polymer solution behavior, and, (ii) to establish a theoretical
program that will advance the currently nascent developments introduced
by our group, to the stage of formulating constitutive equations that
can accurately capture the entire gamut of the rheological response of
polymer solutions.
Collaborators
1. T. Sridhar, Monash University
2. E. S. G. Shaqfeh, Stanford University
3. B. Duenweg, Max Planck Institute for Polymer Research
4. P. Sunthar, IIT Mumbai
5. S. K. Pattanayek, IIT Delhi
6. R. Prabhakar, Monash University
Funding
1. New Staff Member Research Fund, Monash University
2. Victorian Partnership for Advanced Computing, Expertise Grant Scheme
3. Australian Partnership for Advanced Computing, Merit Allocation Scheme
4. Engineering Faculty Grants Scheme, Monash University
Conference Presentations and Publications on this topic
20. S K Pattanayek, and J. R. Prakash, "Is the electrostatic blob model relevant to dilute polyelectrolyte solutions undergoing shear flow?", Macromolecules, 41, 2260-2270 (2008).
19. J. T. Bosko, and J. R. Prakash, "Effect of molecular topology on the transport properties of dendrimers in dilute solution at theta temperature: A Brownian dynamics study", J. Chem. Phys., 128, 034902 (2008).
18. T. T. Pham, P. Sunthar, and J. R. Prakash, "An alternative to the bead-rod model: Bead-spring chains with successive fine graining", J. Non-Newtonian Fluid Mech., 149, 9-19 (2008).
17. T. Sridhar, Duc At Nguyen, R. Prabhakar, and J. R. Prakash, "Rheological Observation of Glassy Dynamics of Dilute Polymer Solutions in Elongational Flows near the Coil-Stretch Transition", Phys. Rev. Lett., 98, 167801 (2007).
16. P. Sunthar, and J. R. Prakash, "Dynamic scaling in dilute polymer solutions: The importance of Dynamic Correlations", Europhysics Letters, 75, 77-83 (2006).
15. R. Prabhakar, J. R. Prakash, and T. Sridhar, "Effect of configuration-dependent intramolecular hydrodynamic interaction on elastocapillary thinning and breakup of filaments of dilute polymer solutions", J. Rheol., 506, 925-947 (2006).
14. R. Prabhakar, and J. R. Prakash, "Gaussian approximation for finitely extensible bead-spring chains with hydrodynamic interaction", J. Rheol., 50, 561-593 (2006).
13. R. Prabhakar and J. R. Prakash, "Fast
and accurate closure approximations for bead-spring models of dilute polymer
solutions", ANZIAM J. 46 (E), C379—C393 (2005).
12. P. Sunthar and J. Ravi Prakash, "Prediction
of chain length effects in elongational flows of dilute polymer solutions
by successive fine graining", ANZIAM J. 46 (E), C320—C335
(2005).
11. R. Prabhakar, J. R. Prakash, and T. Sridhar, “A
successive fine-graining scheme for predicting the rheological properties
of dilute polymer solutions”, J. Rheol. 48, 1251-1278 (2004).
10. K. S. Kumar, and J. R. Prakash, “Universal
consequences of the presence of excluded volume interactions in dilute
polymer solutions undergoing shear flow”, J. Chem. Phys. 121,
3886-3897 (2004).
9. R. Prabhakar, P. Sunthar, and J.R. Prakash, “Exploring
the universal dynamics of dilute polymer solutions in extensional flows”,
Physica A 339, 34-39 (2004).
8. R. Prabhakar and J.R. Prakash, "Multiplicative
separation of the influences of excluded volume, hydrodynamic interactions
and finite extensibility on the rheological properties of dilute polymer
solutions", J. Non-Newtonian Fluid Mech. 116, 163-182 (2004).
7. K. S. Kumar, and J. R. Prakash, "Equilibrium
swelling and universal ratios in dilute polymer solutions: Exact Brownian
dynamics simulations for a delta function excluded volume potential",
Macromolecules 36, 7842-7856 (2003).
6. J. R. Prakash, “Rouse
chains with excluded volume interactions: Steady simple shear flow”,
J. Rheol. 46, 1353-1380 (2002).
5. R. Prabhakar, and J. R. Prakash, “Hookean
Dumbbells with Excluded Volume and Hydrodynamic Interactions”,
J. Rheol. 46, 1191-1220 (2002).
4. J. R. Prakash, “The
influence of the range of excluded volume interactions on the linear viscoelastic
properties of dilute polymer solutions”, Chem. Eng. Sci. 56,
5555-5564 (2001).
3. J. R. Prakash, “Rouse
chains with excluded volume interactions: Linear viscoelasticity”,
Macromolecules 34, 3396-3411 (2001).
2. J. R. Prakash, and H. C. Öttinger, “Viscometric
functions for a dilute solution of polymers in a good solvent”,
Macromolecules 32, 2028-2043 (1999).
1. J. R. Pakash, and H. C. Öttinger, Universal
Viscometric Functions for Dilute Polymer Solutions, J. Non-Newtonian
Fluid Mech. 71, 245 (1997).
 |
27. J. R. Prakash, Glassy Dynamics in Dilute Polymer Solutions near the Coil-Stretch Transition, SERC School/CEP Course and Symposium on Rheology of Complex Fluids, February 18-22, 2008, IIT Bombay, Mumbai, India.
26. J. R. Prakash, Glassy Dynamics in Dilute Polymer Solutions, Tri-University Workshop, December 6-7, 2007, Monash University, Melbourne, Australia (Keynote Lecture).
25. J. R. Prakash, Is the Blob model applicable to dilute polyelectrolyte solutions undergoing shear flow?, SOR 79th Annual Meeting, October 7-11, 2007, Salt Lake City, Utah, USA.
24. J. R. Prakash, Micro & Macro in the Dynamics of Polymer Solutions, Korean-Australian Rheology Conference 2007, September 16-18, 2007, Jeju Island, Korea (Plenary Lecture).
23. J. R. Prakash, Bulk Stress Hysteresis and Driven Glassy Dynamics in Extensional Flows of Polymer Solutions, AIChE Annual Meeting, Nov. 12-Nov. 16, 2006, San Francisco, USA.
22 T. T. Pham, P. Sunthar and J. R. Prakash, “Comparison of Bead-Spring and Bead-Rod Models for Dilute Polymer Solutions: Validation of the Successive Fine Graining Method,” CHEMECA 2006, Auckland, New Zealand, 17 - 20 Sep., 2006.
21. J. R. Prakash, Convergence of Experiment and Theory for Dilute Polymer Solutions with Successive Fine Graining, International Workshop on Mesoscale and Multiscale Description of Complex Fluids, July 5-July 8, 2006, Prato, Italy.
20. R. Prabhakar, J R. Prakash, and T Sridhar, Influence of configuration-dependent drag on the capillary thinning of filaments of dilute polymer solutions, Society of Rheology 77th Annual Meeting, 12–16 October 2005, Vancouver, Canada.
19. R. Prabhakar and J. R. Prakash, “A fast and accurate model for predicting the behaviour of dilute polymer solutions in complex flows,” CHEMECA 2005, Brisbane, Australia, 25 - 28 Sep., 2005.
18. P. Sunthar, Y. W. Ooi, J R. Prakash, “Hydrodynamic radius of a flexible polymer in a dilute solution under theta-conditions,” CHEMECA 2005, Brisbane, Australia, 25 - 28 Sep., 2005.
17. J. R. Prakash, Understanding and Predicting the Dynamics of Dilute Polymer Solutions, Australian-Korean Rheology Conference, 17– 20 July 2005, Cairns, Australia, (Keynote)
16. R. Prabhakar, J. R. Prakash, “Modelling the stress-conformational hysteresis in uniaxial extensional flows of dilute polymer solutions,” Fourteenth International Congress on Rheology, Seoul, South Korea, 22 Aug. - 27 Aug., 2004.
15. P. Sunthar, J. R. Prakash, “Static and Dynamic Properties of Dilute Polymer Solutions: Brownian Dynamics Simulations of the Influence of Excluded Volume and Hydrodynamic Interactions,” Fourteenth International Congress on Rheology, Seoul, South Korea, 22 Aug. - 27 Aug., 2004.
14. P. Sunthar, R. Prabhakar, J. R. Prakash, “Rescaling of Excluded Volume and Hydrodynamic Interaction Parameters in Bead Spring Chain Models with Finitely Extensible Springs,” Fourteenth International Congress on Rheology, Seoul, South Korea, 22 Aug. - 27 Aug., 2004.
13. P Sunthar, and J. R. Prakash, Nonlinear Bead Spring Chain Models for Dilute Polymer Solutions: Rescaled Intra-Molecular Interactions and Successive Fine Graining, 22nd IUPAP International Conference on Statistical Physics, STATPHYS 22, 4-9 July 2004, Bangalore, India.
12. R. Prabhakar, P. Sunthar, and J.R. Prakash, Unravelling the Dynamics of Polymer Solutions in Extensional Flows, New Materials and Complexity, 3-7 November 2003, Kioloa, Australia.
11. R. Prabhakar and J. R. Prakash, Parameter-Free Predictions of the Behavior of Dilute Polymer Solutions in Extensional Flows: Comparison with Experiment, Society of Rheology 75th Annual Meeting, 12-16 October 2003, Pittsburgh, USA.
10. K. S. Kumar, and J. R. Prakash, “Universal shear rate dependence of the viscosity of dilute polymer solutions in the presence of excluded volume interactions", CHEMECA 2003, 31st Australasian Chemical Engineering Conference, Adelaide, South Australia, September 2003.
9. R. Prabhakar and J.R. Prakash, Prediction of Rheological Properties of Dilute Polymer Solutions in Extensional Flows, Korean-Australian Rheology Conference, Gyeongju, Korea, 24-26 September 2003.
8. J. R. Prakash, Molecular Rheology of Dilute Polymer Solutions, Mini-Symposium on Flows of Complex Fluids, 5th International Congress on Industrial and Applied Mathematics, ICIAM 2003, 7-9 July 2003, Sydney, Australia (Invited speaker).
7. R. Prabhakar, and J. R. Prakash, Superposition of Finite Extensibility, Hydrodynamic Interaction and Excluded Volume Effects in Bead-Spring Chain Molecules for Dilute Polymer Solutions, XIIIth International Workshop on Numerical Methods for Non-Newtonian Flows, 4-7 June 2003, Lausanne, Switzerland.
6. R. Prabhakar, and J. R. Prakash, Brownian dynamics simulations of Rouse Chains with Excluded Volume and Hydrodynamic Interactions, 6th European Conference on Rheology, EURHEO, 1–6 September 2002, Erlangen, Germany.
5. J. R. Prakash and R. Prabhakar, Gaussian approximation for Hookean dumbbells with hydrodynamic interaction and excluded volume, Australian-Korean Rheology Conference, 20–21 September 2001, Melbourne, Australia.
4. J. R. Prakash, “Rouse Chains with Excluded Volume Interactions in Steady Shear Flow: Comparison of Brownian Dynamics Simulations with the Gaussian Approximation”, 6th World Congress of Chemical Engineering, 23-27 September 2001, Melbourne, Australia, Paper 1090.
3. J. R. Prakash, “Material functions for Rouse chains with excluded volume interactions in simple shear flows”, Proceedings of the XIIIth International Congress on Rheology, 20-25 August 2000, Cambridge, UK, Vol. 1, 338-339.
2. J. R. Prakash, The Kinetic Theory of Dilute Solutions of Flexible Polymers: Hydrodynamic Interaction, in Advances in the Flow and Rheology of Non-Newtonian Fluids, D.A. Siginer, D.De Kee and R.P. Chabra, eds., Elsevier Science, (1999).
1. J. R. Prakash, The Prediction of Universal Viscometric Functions for Dilute Polymer Solutions under Theta Conditions, in Dynamics of Complex Fluids, M. J. Adams, R. A. Mashelkar, J. R. A. Pearson, A. R. Rennie, eds., Imperial College Press-The Royal Society, (1998).