Colloidal layer deposition with a controllable number of layers and compositional order

TL;DR

This paper presents a DNA-based method to precisely control the number of layers and compositional order in colloidal self-assembled structures, validated through theory and simulations.

Contribution

It introduces a novel design leveraging DNA reaction kinetics to regulate aggregate thickness and composition in colloidal assemblies.

Findings

Controlled the number of layers in colloidal aggregates.

Achieved compositional order by engineering DNA reaction kinetics.

Validated the approach with theory and reaction-diffusion simulations.

Abstract

We design a system with a binary suspension of colloids and a surface that triggers the self-assembly of crystallites with a finite thickness. The proposed design allows controlling the number of layers forming the aggregate and constrains the two types of particles to lie on different planes. These functionalities are achieved by decorating the colloids and the surface with multiple DNA oligomers featuring specific interactions. The surface triggers a chain of reactions between DNA oligomers, leading to localized self-assembly. Equilibrium principles control the thickness of the aggregates. Instead, compositional order is achieved by engineering the reaction kinetics between DNA oligomers in a way that limits interactions between colloids of the same type. We validate our design using theory and reaction-diffusion simulation algorithms, which capture the multibody nature of the interactions. This work demonstrates how engineering the kinetics provides a new avenue for controlling the morphology of aggregates assembled by DNA.