Sliding grafted polymer layers

TL;DR

This paper provides a theoretical analysis of sliding grafted polymer layers, revealing how their structure varies from symmetric to asymmetric configurations depending on graft density and geometry.

Contribution

It introduces a theoretical framework for understanding the structure of sliding grafted polymer layers, highlighting the effects of topology and density on chain configurations.

Findings

Grafts in the mushroom regime are mainly symmetric.

Dense layers are highly asymmetric with one branch dominating.

Intermediate behavior observed in small colloids and star-like micelles.

Abstract

We study theoretically the structure of sliding grafted polymer layers or SGP layers. These interfacial structures are built by attaching each polymer to the substrate with a ring-like molecule such as cyclodextrins. Such a topological grafting mode allows the chains to freely slide along the attachment point. Escape from the sliding link is prevented by bulky capping groups. We show that grafts in the mushroom regime adopt mainly symmetric configurations (with comparable branch sizes) while grafts in dense layers are highly dissymmetric so that only one branch per graft participates in the layer. Sliding layers on small colloids or star-like sliding micelles exhibit an intermediate behavior where the number of longer branches participating in the corona is independent of the total number of branches. This regime also exists for sliding surface-micelles comprising less chains but it is narrower.