Templated self-assembly of gold nanoparticles in smectic liquid crystals confined at 3D printed curved surfaces

TL;DR

This paper demonstrates how 3D-printed curved surfaces can confine liquid crystals to create topological defects that serve as scaffolds for assembling gold nanoparticles into reconfigurable 3D nanostructures, advancing nanomaterials fabrication.

Contribution

It introduces a novel method combining 3D printing and defect engineering in liquid crystals to enable templated self-assembly of gold nanoparticles into complex structures.

Findings

3D-printed curved surfaces effectively confine liquid crystals.

Defect structures can be controlled by surface anchoring and nanoparticle concentration.

Gold nanoparticles assemble into reconfigurable 3D structures guided by liquid crystal defects.

Abstract

The fabrication of assembled structures of topological defects in liquid crystals (LCs) has attracted much attention during the last decade, stemming from the potential application of these defects in modern technologies. A range of techniques can be employed to create large areas of engineered defects in LCs, including mechanical shearing, chemical surface treatment, external fields, or geometric confinement. The technology of 3D printing has recently emerged as a powerful method to fabricate novel patterning topographies inaccessible by other microfabrication techniques, especially confining geometries with curved topographies. In this work, we show the advantages of using 3D-printed curved surfaces and controlled anchoring properties to confine LCs and engineer new structures of topological defects, whose structure we elucidate by comparison with a novel application of Landau-de Gennes free energy minimization to the smectic A-nematic phase transition. We also demonstrate the ability of these defects to act as a scaffold for assembling gold (Au) nanoparticles (NPs) into reconfigurable 3D structures. We discuss the characteristics of this templated self-assembly (TSA) approach and explain the relationship between NP concentrations and defect structures with insights gained from numerical modeling. This work paves the way for a versatile platform of LC defect-templated assembly of a range of functional nanomaterials useful in the field of energy technology.