Location via proxy:   [ UP ]  
[Report a bug]   [Manage cookies]                
  • Editors' Suggestion

Adsorption anomalies in a two-dimensional model of cluster-forming systems

E. Bildanau, J. Pękalski, V. Vikhrenko, and A. Ciach
Phys. Rev. E 101, 012801 – Published 17 January 2020
PDFHTMLExport Citation
Abstract
Authors
Article Text
  • INTRODUCTION
  • THE MODEL AND THE SIMULATION PROCEDURE
  • RESULTS
  • SUMMARY AND CONCLUSIONS
  • ACKNOWLEDGMENTS
    • References

    Abstract

    Adsorption on a boundary line confining a monolayer of particles self-assembling into clusters is studied by Monte Carlo simulations. We focus on a system of particles interacting via competing interaction potential in which effectively short-range attraction is followed by long-range repulsion. For the chemical potential values below the order-disorder phase transition the adsorption isotherms were shown to undergo nonstandard behavior, i.e., the adsorption exhibits a maximum on structural transition between structureless and disordered cluster fluid. In particular, we have found that the adsorption decreases for increasing chemical potential when (i) clusters dominate over monomers in the bulk, (ii) the density profile in the direction perpendicular to the confining line exhibits an oscillatory decay, and (iii) the correlation function in the layer near the adsorption wall exhibits an oscillatory decay in the direction parallel to this wall. Our report indicates striking differences between simple and complex fluid adsorption processes.

    • Figure
    • Figure
    • Figure
    • Figure
    • Figure
    • Figure
    • Figure
    • Received 25 September 2019

    DOI:https://doi.org/10.1103/PhysRevE.101.012801

    ©2020 American Physical Society

    Physics Subject Headings (PhySH)

    1. Research Areas
    AdsorptionAggregationClusteringConfinementEmergence of patterns
    Polymers & Soft Matter

    Authors & Affiliations

    E. Bildanau

    • Belarusian State Technological University, 220006 Minsk, Belarus

    J. Pękalski

    • Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland and Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, USA

    V. Vikhrenko

    • Belarusian State Technological University, 220006 Minsk, Belarus

    A. Ciach

    • Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland

    Article Text (Subscription Required)

    Click to Expand

    References (Subscription Required)

    Click to Expand
    Issue

    Vol. 101, Iss. 1 — January 2020

    Reuse & Permissions
    Access Options
    Author publication services for translation and copyediting assistance advertisement

    Authorization Required

    Log In
    Other Options
    ×

    Images

    • Figure 1
      Figure 1

      The ground states (T*=0) for h=−1,0,1 and for different values of the chemical potential μ*. The snapshots present a region of the slit close to one of the confining walls. Blue and white circles represent occupied and empty sites, correspondingly. Below them the density profiles, ρ(x), along the slit cross section are presented. The lower panel presents regions of stability of the structures [(a)–(n)] in dependence of μ* for the three different values of h. The regions denoted by vac. and cond. correspond to the vacuum and condensed phases, respectively.

      Reuse & Permissions
    • Figure 2
      Figure 2

      Adsorption Γ versus the chemical potential μ* for different values of the wall-particle interaction h at the system temperatures T*=1.0 (left), T*=0.7 (central), and T*=0.5 (right). Γ, T*, and μ* are dimensionless.

      Reuse & Permissions
    • Figure 3
      Figure 3

      The partial adsorption (5) for three values of the chemical potential μ* corresponding to the regions before, at, and after the peak of the adsorption isotherm, at T*=0.5 and h=−1.

      Reuse & Permissions
    • Figure 4
      Figure 4

      The density profiles in the near-wall region for different particle attraction to the wall, h, and for the temperature T*=0.5. There are three values of the chemical potential corresponding to the regions before, at, and after the peak of the adsorption isotherm. The profiles are shown for μ*=−2.6,−2.1 (a), μ*=−2.0,−1.7 (b), and μ*=−1.0,−1.0 (c) for particle-wall interaction h=−2 (solid line) and h=−1 (dashed line).

      Reuse & Permissions
    • Figure 5
      Figure 5

      The average density in the row next to the wall (solid line) and in the bulk (dashed line) at T*=0.5 and for wall-particle interaction h=−1. The derivative of the two densities with respect to the chemical potential is shown in the inset. The turnover of the densities increase occurs at μ*=−1.62.

      Reuse & Permissions
    • Figure 6
      Figure 6

      The distribution of the probabilities for particles to belong to a cluster of size M for different values of the chemical potential at T*=0.5 in the two closest to the wall rows and in the bulk. The partial contributions of different configurations of particles in a cluster of size M are not displayed. Symbols indicate the distributions in the near-wall region (squares, triangles, and circles are used for the chemical potentials μ*=−2.1,−1.7,−1.0, respectively). The filled areas reflect the difference between the probability distribution for certain clusters in the bulk and in the near-wall area. The hatched fillings indicate the probability excess in the border area as compared to the bulk. For μ*=−1.7, P(1)=0.316, and P(4)=0.325 in the bulk. As these values are very close to each other, at this value of the chemical potential the monomer-dominated fluid crosses over to the cluster-dominated fluid.

      Reuse & Permissions
    • Figure 7
      Figure 7

      Correlation functions g1(δy) along the wall for the first row for different values of the chemical potential, which correspond to the states before, at, and after the maximum of the adsorption Γ(μ*) at temperature T*=0.5 and the particle-wall interaction energy h=−1.

      Reuse & Permissions
    ×

    Sign up to receive regular email alerts from Physical Review E

    Log In

    Cancel
    ×

    Search

    Article Lookup

    Paste a citation or DOI
    Enter a citation
    ×