Flexible Polymer Chains in Elongational Flow

The behavior of polymer solutions in simple shear flows has been the subject of considerable research in the past. On the other hand, reports on polymers in elongational flow have appeared comparatively recently in the literature. Elongational flow with an inherent low vorticity is known to be more effective in extending polymer chains than simple shear flow and thus is more interesting from the point of view of basic (molecular chain dynamics at high deformation) and applied polymer science (rheology, fiber extrusion, drag reduction, flow through porous media). Undoubtly, one landmark in the field of polymer dynamics in elongational flow was the notion of critical strain-rate for chain extension, initially put forward by A. Peterlin (1966) and later refined into the "coil-stretching" transition by P. G. de Gennes and H. Hinch (1974). In the two decades which followed, significant progress in the understanding of chain conformation in "strong" flow has been accomplished through a combination of advances in instrumentation, computation techniques and theoretical studies. As a result of the multidisciplinary nature of the field, information on polymer chains in "strong" flow is accessible only from reviews and research papers scattered in disparate scientific journals. An important objective of this book is to remedy that situation by providing the reader with up-to-date knowledge in a single volume. The editors therefore invited leading specialists to provide both fundamental and applied information on the multiple facets of chain deformation in elongational flow.

1 Tortured Chains: An Introduction. - 2 Polymer Solutions in Flow: A Non-Equilibrium Molecular Dynamics Approach. - 2. 1 Introduction. - 2. 2 Molecular Dynamics of Dilute Solutions of Chains in Homogeneous Flow. - 2. 3 The Equilibrium Case. - 2. 4 Polymers in Shear Flow. - 2. 5 Transient Behavior of a Nine-Bead Chain in Elongational Flow. - 2. 6 Conclusions and Perspectives. - List of Symbols and Abbreviations. - References. - 3 Tethered Polymer Chains Under Strong Flows: Stems and Flowers. - 3. 1 Introduction. - 3. 2 Chains Immersed in a Pure Solvent. - 3. 3 Tethered Chains Immersed in a Polymer Solution. - 3. 4 Tethered Chains in Poor Solvents. - 3. 5 Tethered Chains Confined in a Slit. - 3. 6 Concluding Remarks. - References. - 4 Osmotic Pressure in Solutions of Stretched Polymers. - 4. 1 Introduction. - 4. 2 Semi-Dilute Solution of Stretched Polymers. - 4. 3 Discussion. - References. - 5 Stretching of Polyelectrolytes in Elongational Flow. - 5. 1 Introduction. - 5. 2 Experimental Evidence. - 5. 3 Early Theoretical Approaches. - 5. 4 Equilibrium Conformation of the Polyelectrolyte Chain. - 5. 5 Stretching Transition in the Polyelectrolyte Chain. - 5. 6 Conclusions and Discussion. - List of Symbols and Abbreviations. - References. - 6 Calculation of Flows with Large Elongational Components: CONNFFESSIT Calculation of the Flow of a FENE Fluid in a Planar 10:1 Contraction. - 6. 1 Introduction. - 6. 2 CONNFFESSIT. - 6. 3 Geometry of the Planar Contraction Flow Problem. - 6. 4 The Polymeric Fluid. - 6. 5 The Time-Marching Procedure. - 6. 6 Algorithms. - 6. 7 Initial and Boundary Conditions. - 6. 8 Continuum-Mechanical and Molecular Results. - 6. 9 Summary. - List of Symbols and Abbreviations. - References. - 7 Polymer Solutions in Strong Stagnation Point Extensional Flows. - 7. 1 Introduction. - 7. 2 Theory and Modelling of Stretching Macromolecules. - 7. 3 Experimental Realization. - 7. 4 Chain Stretching in Dilute Solutions. - 7. 5 Semi-Dilute Solution Behaviour. - 7. 6 Extensional Viscometry. - 7. 7 Thermomechanical Degradation. - 7. 8 Conclusions. - References. - 8 Birefringence of Dilute PS Solutions in Abrupt Contraction Flow. - 8. 1 Introduction. - 8. 2 Realization of Abrupt Contraction Flow. - 8. 3 Flow Birefringence Measurements. - 8. 4 Experimental Results. - 8. 5 Discussion. - 8. 6 Prospects and Conclusions. - 8. 6. 1 Final Words. - Appendix A. - Appendix B. - Appendix C. - List of Symbols and Abbreviations. - References. - 9 The Hydrodynamics of a DNA Molecule in a Flow Field. - 9. 1 Introduction. - 9. 2 Calculation of the Drag Coefficient. - 9. 3 Stretching Experiments with Longer DNA Molecules. - 9. 4 Hydrodynamic Model for DNA. - 9. 5 Simulation Results. - 9. 6 Discussion. - Appendix: Model Validation. - List of Symbols and Abbreviations. - References. - 10 Single Polymers in Elongational Flows: Dynamic, Steady-State, and Population-Averaged Properties. - 10. 1 Introduction. - 10. 2 Previous Experimental Work. - 10. 3 Experimental Technique. - 10. 4 Experimental Results. - 10. 5 Summary. - 10. 6 Future Prospects. - List of Symbols and Abbreviations. - References. - 11 The Rheology of Polymer Solutions in Porous Media. - 11. 1 Introduction. - 11. 2 Fluid Dynamics Characterization of Porous Media Flows. - 11. 3 Non-Newtonian Behavior in the Flow of Polymer Solutions Through Porous Media. - 11. 4 Flow-Induced Degradation. - 11. 5 Porous Media Flows of Polymer Blends and Cross-Linked Polymers in Solution. - 11. 6 Concluding Remarks. - List of Symbols and Abbreviations. - References.