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Particulate and continuum mechanics of microgel pastes: effect and non-effect of compositional heterogeneity

Abstract

Microgels are deformable colloids that can be packed by external compression; such packing transforms a suspension of loose microgels into a viscoelastic paste with mechanical properties controlled by the elasticity of the constituent particles. We aim to understand how the presence of microgel particles with different individual elastic moduli affects this interplay in heterogeneous microgel packings. We do this by preparing microgel pastes that contain both soft, loosely cross-linked and stiff, densely cross-linked microgel particles and probe their shear elasticity. We consider particle packing fractions that cover the range from particles at the onset of contact to particles that are strongly packed, deformed, and deswollen to investigate the transition from a particulate suspension to a macrogel-type system. These studies reveal that the elasticity of heterogeneous microgel suspensions at low packing is due to the response of the soft, easily deformable microgel particles alone, whereas at high packing both soft and stiff microgels linearly add to the paste elasticity. This fundamental difference is due to the fundamentally different origin of elasticity at different microgel packing; whereas the soft particle interaction potential dominates the suspension mechanics at low microgel packing, rubber-like elasticity that equally reflects both soft and stiff contributions governs the mechanics of the same samples at high microgel packing.

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References

  1. 1.

    Funke W, Okay O, Joos-Muller B (1998) Microgels—intramolecularly crosslinked macromolecules with a globular structure. Adv Polym Sci 136:139–234

  2. 2.

    Heyes DM, Branka AC (2009) Interactions between microgel particles. Soft Matter 5:2681–2685

  3. 3.

    Fernandez-Nieves A, Fernandez-Barbero A, Vincent B, de las Nieves FJ (2003) Osmotic de-swelling of ionic microgel particles. J Chem Phys 119:10383–10388

  4. 4.

    Le Grand A, Petekidis G (2008) Effects of particle softness on the rheology and yielding of colloidal glasses. Rheol Acta 4:579–590

  5. 5.

    Senff H, Richtering W (1999) Temperature sensitive microgel suspensions: colloidal phase behavior and rheology of soft spheres. J Chem Phys 111:1705–1711

  6. 6.

    Seth JR, Cloitre M, Bonnecaze RT (2006) Elastic properties of soft particle pastes. J Rheol 50:353–376

  7. 7.

    Menut P, Seiffert S, Sprakel J, Weitz DA (2012) Does size matter? Elasticity of compressed suspensions of colloidal- and granular-scale microgels. Soft Matter 8:156–164

  8. 8.

    Cloitre M, Borrega R, Monti F, Leibler L (2003) Structure and flow of polyelectrolyte microgels: from suspensions to glasses. C R Physique 4:221–230

  9. 9.

    Wyart M (2011) Elasticity of soft particles and colloids near the jamming threshold. In: Fernandez-Nieves A, Wyss HM, Mattsson J, Weitz DA (eds) Microgel suspensions: fundamentals and applications. Wiley, Berlin, pp 195–206

  10. 10.

    Lietor-Santos J, Sierra-Martın B, Fernandez-Nieves A (2011) Bulk and shear moduli of compressed microgel suspensions. Phys Rev E Rap Comm 84:060402

  11. 11.

    Di Lorenzo F, Seiffert S (2013) Macro- and microrheology of heterogeneous microgel packings. Macromolecules 46:1962–1972

  12. 12.

    McPhee W, Tam KC, Pelton R (1993) Poly(N-isopropylacrylamide) latices prepared with sodium dodecyl sulfate. J Colloid Interface Sci 3:24–30

  13. 13.

    http://www.brocku.ca/researchers/peter_rand/osmotic/osfile.html

  14. 14.

    Meeker SP, Bonnecaze RT, Cloitre M (2004) Slip and flow in pastes of soft particles: direct observation and rheology. J Rheol 48:1295–1320

  15. 15.

    Seth JR, Cloitre M, Bonnecaze RT (2008) Influence of short-range forces on wall-slip in microgel pastes. J Rheol 52:1241–1268

  16. 16.

    Paulin SE, Ackerson BJ, Wolfe MS (1996) Equilibrium and shear induced nonequilibrium phase behavior of PMMA microgel spheres. J Colloid Interface Sci 178:251–262

  17. 17.

    Senff H, Richtering W, Nordhausen C, Weiss A, Ballauff M (1999) Rheology of a temperature sensitive core-shell latex. Langmuir 15:102–106

  18. 18.

    Koumakis N, Pamvouxoglou A, Poulosa AS, Petekidis G (2012) Direct comparison of the rheology of model hard and soft particle glasses. Soft Matter 8:4271–4284

  19. 19.

    Johnson KL (1985) Contact mechanics. Cambridge University Press, Cambridge

  20. 20.

    Flory PJ (1953) Principles of polymer chemistry. Cornell University Press, Ithaca

  21. 21.

    Stieger M, Richtering W, Pedersen JS, Lindner P (2004) Small-angle neutron scattering study of structural changes in temperature sensitive microgel colloids. J Chem Phys 120:6197–6206

  22. 22.

    Deen GR, Alsted T, Richtering W, Pedersen GS (2011) Synthesis and characterization of nanogels of poly(N-isopropylacrylamide) by a combination of light and small-angle X-ray scattering. Phys Chem Chem Phys 13:3108–3114

  23. 23.

    Scheffold F, Diaz-Leyva P, Reufer M, Braham NB, Lynch I, Harden JL (2010) Brushlike interactions between thermoresponsive microgel particles. Phys Rev Lett 104:128304

  24. 24.

    Romeo G, Pica Ciamarra N (2013) Elasticity of compressed microgel suspensions. Soft Matter 9:5401–5406

  25. 25.

    Lyon LA, Meng M, Singh N, Sorrell CD, St. John A (2009) Thermoresponsive microgel-based materials. Chem Soc Rev 38:865–874

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Acknowledgments

This project was funded by the Focus Area NanoScale at FU Berlin, which is gratefully acknowledged. S. Seiffert is a Liebig Fellow of the Fund of the Chemical Industry (Germany). F. Di Lorenzo is a doctoral student of the Berlin-based Helmholtz Virtual Institute “Multifunctional Materials for Medicine”.

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Correspondence to Sebastian Seiffert.

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Di Lorenzo, F., Seiffert, S. Particulate and continuum mechanics of microgel pastes: effect and non-effect of compositional heterogeneity. Colloid Polym Sci 291, 2927–2933 (2013). https://doi.org/10.1007/s00396-013-3032-8

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Keywords

  • Elasticity
  • Heterogeneity
  • Mechanics
  • Microgel
  • Particulate
  • Paste