Confetti Ordering by Polymer Brushes

TL;DR

This paper investigates how dilute platelet additives orient and position themselves within end-grafted polymer brushes, influenced by interactions and geometric ratios, affecting their suspension or invasion into the brush interior.

Contribution

It introduces a model describing the orientation and positioning of platelet additives in polymer brushes based on interaction ratios and geometric parameters.

Findings

Platelets either stay at the surface or invade the interior depending on conditions.

Orientation is controlled by size ratios and interaction strengths.

The model predicts conditions for platelet protrusion or surface suspension.

Abstract

I consider the ordering of dilute platelet additives when incorporated into an end-grafted polymer brush. The competition between wetting interactions and the anisotropic stress environment of the interior of the brush causes these platelet additives to either remain suspended at the outer edge of the brush laying flat against the brush surface (as bits of confetti at rest on the ground), or to invade the interior of the brush in which case the platelets stand end-on and in some cases protrude above the outer edge of the brush. The orientation of the additives is controlled by the ratio of the diameter of the additive to the thickness of the bare brush, as well as the ratio of solvent-monomer and solvent-platelet interactions.