Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

Asymmetric caging in soft colloidal mixtures


The long-standing observations that different amorphous materials exhibit a pronounced enhancement of viscosity and eventually vitrify on compression or cooling continue to fascinate and challenge scientists1, on the ground of their physical origin and practical implications. Glass formation is a generic phenomenon, observed in physically quite distinct systems that encompass hard and soft particles. It is believed that a common underlying scenario2,3, namely cage formation, drives dynamical arrest, especially at high concentrations. Here, we identify a novel, asymmetric glassy state in soft colloidal mixtures, which is characterized by strongly anisotropically distorted cages, bearing similarities to those of hard-sphere glasses under shear. The anisotropy is induced by the presence of soft additives. This phenomenon seems to be generic to soft colloids and its origins lie in the penetrability of the constituent particles. The resulting phase diagram for mixtures of soft particles is clearly distinct from that of hard-sphere mixtures and brings forward a rich variety of vitrified states that delineate an ergodic lake in the parameter space spanned by the size ratio between the two components and by the concentration of the additives. Thus, a new route opens for the rational design of soft particles with desired tunable rheological properties.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Experimental and MCT arrested state diagrams for star–star mixtures.
Figure 2: Rheological properties for star–star mixtures from experiments and MCT calculations.
Figure 3: Dynamical properties of star–star mixtures based on numerical simulations.
Figure 4: Structural properties of star–star mixtures and visualization of the asymmetric cages, based on numerical simulations.

Similar content being viewed by others


  1. Editorial.So much more to know. Science 309, 78–102 (2005).

  2. Angell, C. A. Formation of glasses from liquids and biopolymers. Science 267, 1924–1935 (1995).

    Article  CAS  Google Scholar 

  3. Liu, A. J. & Nagel, S. R. Nonlinear dynamics—Jamming is not just cool any more. Nature 6706, 21–22 (1998).

    Article  Google Scholar 

  4. Pusey, P. N. & van Megen, W. Phase behaviour of concentrated suspensions of nearly hard colloidal spheres. Nature 320, 340–342 (1986).

    Article  CAS  Google Scholar 

  5. Cohen, E. G. D. & de Schepper, I. M. Note on transport processes in dense colloidal suspensions. J. Stat. Phys. 63, 241–248 (1991).

    Article  Google Scholar 

  6. Weeks, E. R., Crocker, J. C., Levitt, A. C., Schofield, A. C. & Weitz, D. A. Three-dimensional direct imaging of structural relaxation near the colloidal glass transition. Science 287, 627–631 (2000).

    Article  CAS  Google Scholar 

  7. Barrat, J.-L., Götze, W. & Latz, A. The liquid-glass transition of the hard-sphere system. J. Phys. Condens. Matter 1, 7163–7170 (1989).

    Article  Google Scholar 

  8. Dawson, K. A. et al. Higher order glass transition singularities in colloidal systems. Phys. Rev. E 63, 011401 (2001).

    Article  CAS  Google Scholar 

  9. Grest, G. S., Fetters, L. J., Huang, J. S. & Richter, D. Star polymers: Experiment, theory, and simulation. Adv. Chem. Phys. XCIV, 67–163 (1996).

    Google Scholar 

  10. Vlassopoulos, D., Fytas, G., Pakula, T. & Roovers, J. Multiarm star polymers dynamics. J. Phys. Condens. Matter 13, R855–R876 (2001).

    Article  CAS  Google Scholar 

  11. Pham, K. N. et al. Multiple glassy states in a simple model system. Science 296, 104–106 (2002).

    Article  CAS  Google Scholar 

  12. Zaccarelli, E. et al. Confirmation of anomalous behaviour in short-ranged attractive colloids. Phys. Rev. E 66, 041402 (2002).

    Article  CAS  Google Scholar 

  13. Imhof, A. & Dhont, J. K. G. Experimental phase diagram of a binary colloidal hard-sphere mixture with a large size ratio. Phys. Rev. Lett. 75, 1662–1665 (1995).

    Article  CAS  Google Scholar 

  14. Vermant, J. & Solomon, M. J. Flow-induced structure in colloidal suspensions. J. Phys. Condens. Matter 17, R187–R216 (2005).

    Article  CAS  Google Scholar 

  15. Besseling, R., Weeks, E. R., Schofield, A. B. & Poon, W. C. K. Three-dimensional imaging of colloidal glasses under steady shear. Phys. Rev. Lett. 99, 028301 (2007).

    Article  CAS  Google Scholar 

  16. Zaccarelli, E. et al. Tailoring the flow of soft glasses by soft additives. Phys. Rev. Lett. 95, 268301 (2005).

    Article  CAS  Google Scholar 

  17. Götze, W. in Liquids, Freezing and Glass Transition (eds Hansen, J.-P., Levesque, D. & Zinn-Justin, J.) 287 (North-Holland, Amsterdam, 1991).

    Google Scholar 

  18. Cloitre, M., Borrega, R., Monti, F. & Leibler, L. Glassy dynamics and flow properties of soft colloidal pastes. Phys. Rev. Lett. 90, 068303 (2003).

    Article  Google Scholar 

  19. Cicuta, P. & Donald, A. M. Microrheology: A review of the method and applications. Soft Matter 3, 1449–1455 (2007).

    Article  CAS  Google Scholar 

  20. Duoss, E., Twardowski, M. & Lewis, J. A. Sol–gel inks for direct-write assembly of functional oxides. Adv. Mater. 19, 3485–3489 (2007).

    Article  CAS  Google Scholar 

  21. Widawski, G., Rawiso, M. & Francois, B. Self-organized honeycomb morphology of star-polymer polystyrene films. Nature 369, 387–389 (1994).

    Article  CAS  Google Scholar 

  22. Soppimath, K. S., Tan, D. C.-W. & Yang, Y.-Y. pH-triggered thermally responsive polymer core–shell nanoparticles for drug delivery. Adv. Mater. 17, 318–323 (2005).

    Article  CAS  Google Scholar 

  23. Cottin, X. & Monson, P. A. Substitutionally ordered solid solutions of hard spheres. J. Chem. Phys. 102, 3354–3360 (1995).

    Article  CAS  Google Scholar 

Download references


Helpful discussions with J. Roovers are gratefully acknowledged. This work has been supported by the Marie Curie Network on Dynamical Arrest of Soft Matter and Colloids MRTNCT-2003-504712, the NoE SoftComp NMP3-CT-2004-502235 and the DFG through the SFB TR6. C.M. acknowledges financial support by the Alexander von Humboldt Foundation.

Author information

Authors and Affiliations


Corresponding authors

Correspondence to C. Mayer or E. Zaccarelli.

Supplementary information

Supplementary Information

Supplementary Information (PDF 183 kb)

Rights and permissions

Reprints and permissions

About this article

Cite this article

Mayer, C., Zaccarelli, E., Stiakakis, E. et al. Asymmetric caging in soft colloidal mixtures. Nature Mater 7, 780–784 (2008).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

This article is cited by


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing