Semiempirical Model for Adsorption of Binary Mixtures

As it can clearly be observed in Figure 1a and 2a in the paper, the total coverage of the biggest species (in this case k = 6) has a maximum and later decreases to a limit value. This behavior is known as adsorption preference reversal (APR) and has also been observed in theoretical calculations and Monte Carlo simulations [1, 2]. The APR phenomenon usually is attributed to presence of repulsive mutual interactions. The introduction of repulsive mutual interactions is a fictitious or effective way of taking into account geometric or steric effects between two species of different size. In this supplementary material we explain how this effect can be easily understood from an entropic point of view. Let us consider the adsorption of a binary mixture of hard rigid rods on one-dimensional lattices[3] at low pressures. In this case, the system behaves as single-component system and therefore, we can use the exact one-dimensional isotherm and the configurational entropy per site for k-mers [4],