Polymer Brush in a Nanopore: Effects of Solvent Strength and Macromolecular Architecture Studied by Self-Consistent Field and Scaling Theory.

Mikhail Y Laktionov,Oleg V Borisov,Ralf P Richter,Ekaterina B Zhulina

doi:10.3390/polym13223929

Abstract

To study conformational transition occuring upon inferior solvent strength in a brush formed by linear or dendritically branched macromolecules tethered to the inner surface of cylindrical or planar (slit-like) pore, a self-consistent field analytical approach is employed. Variations in the internal brush structure as a function of variable solvent strength and pore radius, and the onset of formation of a hollow channel in the pore center are analysed. The predictions of analytical theory are supported and complemented by numerical modelling by a self-consistent field Scheutjens–Fleer method. Scaling arguments are used to study microphase segregation under poor solvent conditions leading to formation of a laterally and longitudinally patterned structure in planar and cylindrical pores, respectively, and the effects of confinement on "octopus-like" clusters in the pores of different geometries.

Highlights

Polymer brushes are layers of macromolecules tethered by terminal segments to a solid substrate and immersed in a solvent [1,2,3,4,5]
Since partitioning in and transport through polymer decorated nanopores can be regulated by conformational changes in the brush, it is important to understand the pecularities of the swelling-to-collapse conformational transitions occuring in the polymer brush tethered to the inner surface of the pores as a function of the solvent quality
The aim of the present paper is to study conformational transitions in brushes formed by polymers with arbitrary architecture grafted to the inner surface of cylindrical or slit-like pores and immersed into a solvent of arbitrary quality

Summary

Introduction

Polymer brushes are layers of macromolecules tethered by terminal segments to a solid substrate and immersed in a solvent [1,2,3,4,5]. As follows from the figure, at given pore radius R, the pore opening occurs at better solvent strength conditions (i.e., at smaller χ) for dendron brushes than for linear chain brushes.

Polymer Density Distribution in the Pore

Numerical Self-Consistent Field Theory

Clusters in a Brush Confined in the Cylindrical Pore

Discussion and Conclusions