Adsorption from Binary Solutions on the Polymer-Tethered Surfaces

Abstract

A density functional study of adsorption from binary solutions on surfaces modified with tethered chains is presented. The tethered chains are modeled as freely jointed tangent spheres. The fluid molecules are spherical. All species interact via the Lennard-Jones (12-6) potential. The substrate is neutral with respect to all chain segments but the surface-binding segment, and it interacts with the fluid molecules via a Lennard-Jones (9-3) potential. Depending on the parameters of the model, different shapes of the relative excess adsorption isotherms are found. The density profiles of all components are analyzed. It is shown that the surface region is highly inhomogeneous. An influence of the grafting density, the length of grafted chains, the nature of the solution, and its composition on the adsorption mechanism and the structure of the bonded-phase is investigated. The theoretical predictions are consistent with the results of computer simulations and experimental data.

Adsorption on chemically bonded chain layers with embedded active groups

“…, M = M A + M B within a chain) in the form given in Refs. [36][37][38][39][40]. The first segments of chains are bonded to the surface.…”

“…For the competitive adsorption the relative excess adsorption isotherms are usually used [39,40,[59][60][61][62]]…”

“…An increasing awareness of interfaces in biology and medicine has been accompanied by a considerable growth of research of adsorption of spherical molecules, polymers and proteins on surfaces modified with grafted chains [3,[28][29][30][31][32][33][34][35][36][37][38][39][40][41][42]. Various theoretical and simulation methods were used to study the behaviour of particles near the homogeneous bonded C 2014 Taylor & Francis layers.…”

“…The lattice version of SCFT formulated by Scheuntjens and Fleer [34,35] gained considerable popularity. Recently, the density functional approach proposed by Yu and Wu [26,43] was applied to study the adsorption of pure fluids, mixtures and the competitive adsorption from binary solutions [36][37][38][39][40], as well as adsorption of Janus particles [42].…”

Excluded volume effects in compressed polymer brushes: A density functional theory

“…37,38 Previous publications have also demonstrated that DFT can quantitatively capture the characteristics of tethered chains. [39][40][41][42][43][44][45][46][47] Particularly, for a hard-sphere chain model, the DFT can treat the fine details of the excluded volume effects between the segments of the grafted chains explicitly, rather than the simple twobody interactions as in the classical analytic SCF theory. This feature makes the DFT a preferred theoretical framework to investigate the compressed brush systems, especially for the brushes with high grafting densities or at high compressions.…”