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Soft Matter Self-Assembly Dynamics Workshop 2014: Competitive Interactions & Phase Diagrams

Explore unconventional interactions in soft matter, from re-entrant liquids to gel formation. Discover how competitive interactions modulate entropy and enthalpy balance, influencing local structures and phase behaviors. Learn about patchy particle models, DNA implementation, and the stability of networks in soft matter self-assembly dynamics.

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Soft Matter Self-Assembly Dynamics Workshop 2014: Competitive Interactions & Phase Diagrams

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  1. Workshop on Soft Matter Self Assembly and Dynamics, January 9-10th, 2014 Hyderabad. Simple models of competitive interactions in soft-matter: re-entrant liquids and gels on heating Francesco Sciortino http://glass.phys.uniroma1.it/sciortino/

  2. Outline of the talk Unconventional Gas-Liquid Phase Behaviors. Re-entrant liquids (J. Russo, L. Rovigatti, J. Tavares, Texeira, M. Telo da Gama) A patchy particle model that gels on heating (S. Roldan, F. Smallenberg, W. Kob) A possible DNA implementation (F. Romano)

  3. Unconventional (gas-liquid) phase diagrams standard valence-dominated Bianchi et al, PRL 97, 168301, 2006, liquid-dominated Gas-dominated Russo et al PRL 1a06, 085703 (2011); Rovigatti et al Phys.Rev.Lett. 111, 168302 (2013) FS et al PRL 103, 237801 (2009)

  4. Competitive Interactions Modulate the entropy-enthalpy balance to stabilize different local structures: In this talk, the entropy-enthalpy balance promotes the emergence of a structure controlled by energy (stable at low T) which competes with a structure stabilized by entropy at intermediate T.

  5. Tlusty-Safram, Science (2000) Dipolar Hard Spheres… competition between chaining and branching Camp et al PRL (2000)

  6. Can we reproduce this “pinched” phase diagram with a simple patchy model ? Well defined pair-interaction potential Exploit the Wertheim theory as a tool J. M. Tavares, et al Mol. Phys.107, 4532009, Phys. Rev. E80, 021506 2009

  7. PATCHY PARTICLES THAT FORM CHAINS: AA

  8. PATCHY PARTICLES THAT FORM CHAINS: AA ADD BRANCHING POSSIBILITIES AB

  9. How the ground state looks like ? Start from an infinite chain of AA bonds

  10. How the ground state looks like ? Start from an infinite chain of AA bonds Splitting the chain in two parts costs AA

  11. How the ground state looks like ? Start from an infinite chain of AA bonds Splitting the chain in two parts costs AA Joining the two newly created ends provides a gain of -2AB E=AA -2AB>0 AB/AA=0.5 Chaining wins at low T Branching wins even at low T Chains win at low T Branching wins even at low T

  12. Branching at finite T ? Entropy ! Which Entropy ? Bonding Volume Entropy and “configurational” Entropy

  13. A patchy model with a “pinched” phase diagram B/A =0.37 Russo et al PRL 106, 085703 (2011); J. Russo, et al Reentrant Phase Diagram of Network Fluids Phys. Rev. Letts. 106, 085703 (2011)

  14. Evolution of the phase diagram on modulating the branching strength AB

  15. Effective temperature valence

  16. Part II

  17. How do we form an equilibrium gel ? reducing “valence” Small Valence The essence of the gel state of matter

  18. How do we break a gel ? Competing interactions…. Add a new species that compete for the bonding sites Network Blocked particle 2AA 4AB AB< AA /2

  19. How to stabilize the network: Entropy Bonding volume AA >> Bonding volume AB

  20. Forming and melting the gel ! Gel bonds Blocking bonds

  21. Low and high T Intermediate T

  22. Projection in the 4-1 composition ratio (stochiometric mixture) Slower Slower

  23. Can we design a system that does it ?

  24. Experiments: DNA Hydrogels

  25. Phase behavior of DNA hydrogels

  26. Can we realize this with the Biffi et al DNA particles ? STAR-ARM-3’(TGA)GCGTACGC(AAT)-5’ 3’-ATTGCG-5’ 3’-CGCTCA-5’ AA-bonding: 8 bases paired STAR-ARM-3’(TGA)GCGTACGC(AAT)-5’ STAR-ARM-3’(TGA)GCGTACGC(AAT)-5’ 5’-ACTCGC-3’ STAR-ARM-3’-TGAGCGTACGCAAT-5’ AB-bonding: 12 bases paired 5’-GCGTTA-3’ (Flavio Romano)

  27. AA-bonding: 8 bases paired AB-bonding: 12 bases paired

  28. Nupack Evaluations: www.nupack.org DNA Gel bonds Patchy model Blocking bonds Gel bonds Blocking bonds

  29. Conclusions Competitive interactions: very powerful concept for designing sensitive structured materials DNA constructs are very versatile in this respect. Hopefully, DNA re-entrant gels will be realized. Waiting for experimental realization (Milan-Rome)

  30. Thanks to… Emanuela Bianchi, Piero Tartaglia, Emanuela Zaccarelli – Valence Phase Diagram Flavio Romano (Oxford) - DNA gels Walter Kob, (Montpellier), Sandalo Roldan, Frank Smallenburg - Gel on heating John Russo , J. M. Tavares, P. I. C. Teixeira, M. Telo da Gama(Lisbon) - Chaining and Branching Lorenzo Rovigatti - 2D SUS Tommaso Bellini, Roberto Cerbino, Silvia Biffi, Francesca Bomboi – experiments on DNA

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