Towards Polymeric Nanoparticles with Multiple Magnetic Patches.

Elham Yammine,Laurent Adumeau,Stéphane Mornet,Etienne Duguet,Michel Nakhl,Maher Abboud

doi:10.3390/nano11010147

Abstract

Fabricating future materials by self-assembly of nano-building blocks programmed to generate specific lattices is among the most challenging goals of nanotechnology and has led to the recent concept of patchy particles. We report here a simple strategy to fabricate polystyrene nanoparticles with several silica patches based on the solvent-induced self-assembly of silica/polystyrene monopods. The latter are obtained with morphological yields as high as 99% by seed-growth emulsion polymerization of styrene in the presence of 100 nm silica seeds previously modified with an optimal surface density of methacryloxymethyl groups. In addition, we fabricate “magnetic” silica seeds by silica encapsulation of preformed maghemite supraparticles. The polystyrene pod, i.e., surface nodule, serves as a sticky point when the monopods are incubated in a bad/good solvent mixture for polystyrene, e.g., ethanol/tetrahydrofuran mixtures. After self-assembly, mixtures of particles with two, three, four silica or magnetic silica patches are mainly obtained. The influence of experimental parameters such as the ethanol/tetrahydrofuran volume ratio, monopod concentration and incubation time is studied. Further developments would consist of obtaining pure batches by centrifugal sorting and optimizing the relative position of the patches in conventional repulsion figures.

Highlights

Building hierarchical structures with unique properties for both fundamental studies and technological applications is among the most active research areas in nanotechnology.For bottom-up approaches, the main current goal is the preparation of nanoparticles serving as building blocks for controlled assembly [1]
This is evidenced by the diameter of the PS nodule of the monopods, which is systematically much higher than that of the free PS particles that have grown independently from the silica seeds
In the present study,corresponding we showed that the solvent-induced self-assembly is effithe magnetic monopods to entry

Summary

Introduction

Building hierarchical structures with unique properties for both fundamental studies and technological applications is among the most active research areas in nanotechnology.For bottom-up approaches, the main current goal is the preparation of nanoparticles serving as building blocks for controlled assembly [1]. Isotropic spherical nanoparticles lead to only a low number of close-packed colloidal lattices, while anisotropic nanoparticles are able to order into many novel crystalline or non-crystalline structures [2]. In this context, there is great interest in patchy particles envisioned as valence-endowed colloidal atoms for targeting more open lattices and low-coordination architectures [3,4,5,6,7,8].

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