Ordering of Polystyrene Nanoparticles on Substrates Pre-Coated with Different Polyelectrolyte Architectures

Zuleyha Yenice,Regine Klitzing,Matthias Karg

doi:10.3390/ijms140612893

Abstract

Adjusting the inter-particle distances in ordered nanoparticle arrays can create new nano-devices and is of increasing importance to a number of applications such as nanoelectronics and optical devices. The assembly of negatively charged polystyrene (PS) nanoparticles (NPs) on Poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) brushes, quaternized PDMAEMA brushes and Si/PEI/(PSS/PAH)2, was studied using dip- and spin-coating techniques. By dip-coating, two dimensional (2-D), randomly distributed non-close packed particle arrays were assembled on Si/PEI/(PSS/PAH)2 and PDMAEMA brushes. The inter-particle repulsion leads to lateral mobility of the particles on these surfaces. The 200 nm diameter PS NPs tended to an inter-particle distance of 350 to 400 nm (center to center). On quaternized PDMAEMA brushes, the strong attractive interaction between the NPs and the brush dominated, leading to clustering of the particles on the brush surface. Particle deposition using spin-coating at low spin rates resulted in hexagonal close-packed multilayer structures on Si/PEI/(PSS/PAH)2. Close-packed assemblies with more pronounced defects are also observed on PDMAEMA brushes and QPDMAEMA brushes. In contrast, randomly distributed monolayer NP arrays were achieved at higher spin rates on all polyelectrolyte architectures. The area fraction of the particles decreased with increasing spin rate.

Highlights

Of colloidal building blocks is a promising bottom-up concept for the fabrication of new functional materials, which are of interest in a broad range of areas such as nanoelectronics, photovoltaics, spintronics and sensing
In this work we present our studies on PS NP assembly on weak and strong polyelectrolyte brushes and polyelectrolyte multilayers using dip- and spin-coating techniques
The key objective of the present work was the investigation of the effect of surface modification as well as the deposition technique on the assembly of negatively charged PS

Summary

Introduction

Of colloidal building blocks is a promising bottom-up concept for the fabrication of new functional materials, which are of interest in a broad range of areas such as nanoelectronics, photovoltaics, spintronics and sensing. The latter technique creates hexagonal non-close packed 2-D and 3-D particle arrays in a polymer matrix, for the fabrication of periodic nanostructured materials [7,8], biomimetic antireflection coatings [9,10] and for other optical applications [11,12] on large scales. All of these methods, to produce non-close packed ordered arrays, require further modification after the self-assembly process. There is a lack of fundamental understanding of the self-assembly process, which limits our ability to improve the fabrication techniques

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Conclusion