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Kinetic roughening of coffee-ring interfaces

By: Beatriz García Barreales
From: Departamento de Física, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
At: Building C1, room 1.4.14
[2022-06-02] 14:00

We have studied the kinetic roughening behavior of the fronts of coffee-ring aggregates via extensive numerical simulations of the off-lattice model considered for this context in [C. S. Dias et al., Soft Matter 14, 1903 (2018)]. This model describes ballistic aggregation of patchy colloids and depends on a parameter r_AB which controls the affinity of the two patches, A and B. 
For long times, large lattice and all r_AB-values we have found that the dynamic is dominated by the appearance of macroscopic shapes.  The intermediate (time) dynamics is different depending on the value of r_AB.  A detailed analysis of correlation functions shows that the front for the discrete model is always in the moving phase for 0AB≤1and that its kinetic roughening behavior is intrinsically anomalous for r_AB<0.1. Suitable boundary conditions allow us to elucidate a discontinuous pinning transition at r_AB=0, with the front still displaying intrinsic anomalous scaling, but now with unusual exponent values α⋍1.2, α_loc⋍0.5, β⋍1, and z⋍1.2.