Layer-by-layer assembly of colloidal particles deposited onto the polymer-grafted elastic substrate

TL;DR

This paper presents a new method for organizing colloidal particles on polymer-grafted elastic substrates, enabling the formation of highly ordered structures through a layer-by-layer process controlled by polymer brushes and solvent conditions.

Contribution

It introduces a novel theoretical framework for controlling colloid arrangements on elastic substrates using polymer grafting and solvent-driven layer growth.

Findings

Polymer grafting controls colloid dispersion and ordering.

Layer-by-layer growth can be achieved without patterned templates.

Ordered, defect-free colloidal structures are possible with proper parameters.

Abstract

We demonstrate a novel route of spatially organizing the colloid arrangements on the polymer-grafted substrate by use of self-consistent field and density functional theories. We find that grafting of polymers onto a substrate can effectively control spatial dispersions of deposited colloids as a result of the balance between colloidal settling force and entropically elastic force of brushes, and colloids can form unexpected ordered structures on a grafting substrate. The depositing process of colloidal particles onto the elastic "soft" substrate includes two steps: brush-mediated one-dimensional arrangement of colloidal crystals and controlled layer-by-layer growth driven entropically by non-adsorbing polymer solvent with increasing the particles. The result indicates a possibility for the production of highly ordered and defect-free structures by simply using the grafted substrate instead of periodically patterned templates, under appropriate selection of colloidal size, effective depositing potential, and brush coverage density.