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Thermodynamic forces arising from confinement imposed on a polymer coil by interfaces

Thermodynamic forces arising from confinement imposed on a polymer coil by interfaces. Waldemar Nowicki , Grażyna Nowicka. Faculty of Chemistry, A. Mickiewicz University, Grunwaldzka 6, 60-780 Poznań, Poland fax: +48 61 8291 505, E-mail: gwnow@amu.edu.pl. System. Questions.

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Thermodynamic forces arising from confinement imposed on a polymer coil by interfaces

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  1. Thermodynamic forces arising from confinement imposed on a polymer coil by interfaces Waldemar Nowicki, Grażyna Nowicka Faculty of Chemistry, A. Mickiewicz University, Grunwaldzka 6, 60-780 Poznań, Poland fax: +48 61 8291 505, E-mail: gwnow@amu.edu.pl

  2. System

  3. Questions Can the macromolecule escape from the cavity spontaneously? Is there any energetic or entropic barrier which has to be overcome in the course of the escape? How high is the barrier? What the physical nature of the barrier?

  4. Applications • the encapsulation of macromolecules by lipid membranes to form protocellular structures under prebiotic conditions • the introduction of viral DNA to the cytoplasm of bacterial cell • the exchange of a genetic material in the conjugation of bacteria • theprotein translocation across membranes • the gene transduction between bacteria • drug delivery, • ultrarapid DNA sequencing, • separation and purification of synthetic and biological polymers...

  5. Model Linear polymer chain modelled by the self-avoiding walk (SAW): The assumption addresses the problem in the athermal limit, in which only excluded volume interactions are considered. The crucial quantity fully determining the system properties is the conformational entropy.

  6. Model Effects influencing the conformational entropy (geometrical constraints): the confined environment the approach of the terminal segment to the interface the translocation of the chain through the hole

  7. Technical details 1 2 3 the confined environment the approach of the terminal segment to the interface the translocation of the chain through the hole

  8. Technical details • Static Monte Carlo method (sMC) • Statistical counting method (SCM) • Self-avoiding walk (SAW)

  9. Technical details • Self-avoiding walk (SAW) Lattice coordination number equal to 24

  10. Technical details • Statistical counting method (SCM) Effective coordination number Number of conformations Conformational entropy Zhao, D.; Huang, Y.; He, Z.; Qian, R. J. Chem. Phys., 1996, 104, 1672.

  11. Technical details • Statistical counting method (SCM) Effective coordination number

  12. Technical details The thermodynamic generalized forces

  13. 1 Chain compression in a cavity The end-to-end distance vs. segment number dependence for different cavity radii

  14. 1 Chain compression in a cavity Conformational entropy of the chain vs. cavity radius

  15. 1 Entropic pressure in a cavity ...? Conformational pressure of the chain vs. cavity volume

  16. 1 Entropic pressure in a cavity Conformational pressure of the chain vs. cavity volume

  17. 1 Entropic pressure in a cavity Equation of state: Dependence between reduced parameters

  18. 2 The approach of the terminal segment to the interface Total conformational entropy as a function of the distance between terminal segment and the flat wall

  19. 2 The approach of the terminal segment to the interface Reduced conformational entropy as a function of the distance between terminal segment and the flat wall

  20. 2 The approach of the terminal segment to the interface Reduced conformational entropy as a function of the reduced distance between terminal segment and the flat wall

  21. 2 The approach of the terminal segment to the interface

  22. 2 The attachment of the terminal segment to the interface The force is independent on the chain length

  23. 3 The translocation of the chain through the hole Translocation coordinate

  24. 3 The translocation of the chain through the hole Translocation coordinate

  25. 3 The translocation of the chain through the hole Translocation coordinate

  26. 3 The translocation of the chain through the hole Twin cavities

  27. 1+3 The translocation of the chain through the hole The whole landscape of the conformational entropy (translocation through a nanopore in the flat membrane)

  28. 1+3 The translocation of the chain through the hole The force profile

  29. 1+2+3 The translocation of the chain through the hole The whole landscape of the conformational entropy (escape from cavity)

  30. Thank you for your attention

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