Adsorption from binary solutions on chemically bonded phases

TL;DR

This study uses density functional theory to analyze how binary liquid mixtures adsorb on solid surfaces modified with grafted chains, revealing how various parameters influence adsorption behavior.

Contribution

It provides a theoretical framework for understanding adsorption on chemically bonded phases, incorporating detailed modeling of interactions and surface modifications.

Findings

Adsorption is affected by grafting density and chain length.

Surface interactions influence the structure and composition of the adsorbed layer.

Results align with experimental observations.

Abstract

We use density functional theory to investigate adsorption of liquid mixtures on solid surfaces modified with end-grafted chains. The chains are modelled as freely joined spheres. The fluid molecules are spherical. All spherical species interact via the Lennard-Jones (12-6) potential. The Lennard-Jones (9-3) potential describes interactions of solvent molecules with the substrate. We study the relative excess adsorption isotherms, the structure of surface layer and its composition. The impact of the following parameters on adsorption is discussed: the grafting density, the grafted chain length, interactions of solvent molecules with grafted chains and with the substrate, and the presence of active groups in grafted chains. The theoretical results are consistent with experimental observations.