Flexible confinement leads to multiple relaxation regimes in glassy colloidal liquids

Ian Williams, Erdal C. Oğuz, Paul Bartlett, Hartmut Löwen and C. Patrick Royall

Understanding relaxation of supercooled fluids is a major challenge and confining such systems can lead to bewildering behaviour. Here, we exploit an optically confined colloidal model system in which we use reduced pressure as a control parameter. The dynamics of the system are “Arrhenius” at low and moderate pressure, but at higher pressures relaxation is faster than expected. We associate this faster relaxation with a decrease in density adjacent to the confining boundary due to local ordering in the system enabled by the flexible wall.

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