Random sequential adsorption of polyatomic species on fractal substrates

Area of Science:

• Surface science
• Physical chemistry
• Materials science

Background:

• Fractal surfaces exhibit intrinsic heterogeneities affecting adsorption.
• The coordination number of adsorbates depends on adsorbent topology.
• Understanding adsorption on complex surfaces is crucial for materials design.

Purpose of the Study:

• To investigate random sequential adsorption (RSA) of k-mers on fractal substrates.
• To analyze the influence of adsorbate geometry and substrate topology on adsorption kinetics.
• To determine the relationship between surface symmetry and adsorption behavior.

Main Methods:

• Simulating RSA of k-mers with varying sizes and shapes.
• Utilizing both deterministic and statistical fractal surface models.
• Analyzing surface coverage evolution and fitting parameters (jamming coverage, adsorption rates).

Main Results:

• Surface coverage follows a characteristic decay at late stages: θ(t)=θ(j)-Aexp[-t/σ].
• Jamming coverage (θ(j)) and adsorption kinetics (σ) are dependent on adsorbate-adsorbent geometry.
• Substrate symmetry was found to be a critical factor in adsorption kinetics.

Conclusions:

• The geometry of both the adsorbate (k-mers) and the adsorbent (fractal surfaces) dictates adsorption behavior.
• Substrate symmetry plays a decisive role in the adsorption kinetics of polyatomic species.
• Findings provide insights into designing materials with controlled surface adsorption properties.