Phase stability of dispersions of hollow silica nanocubes mediated by non-adsorbing polymers

F Dekker,Á González García,A P Philipse,R Tuinier

doi:10.1140/epje/i2020-11962-y

F Dekker, Á González García + Show 2 more

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https://doi.org/10.1140/epje/i2020-11962-y

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Abstract

.Although there are theoretical predictions (Eur. Phys. J. E 41, 110 (2018)) for the rich-phase behaviour of colloidal cubes mixed with non-adsorbing polymers, a thorough verification of this phase behaviour is still underway; experimental studies on mixtures of cubes and non-adsorbing polymers in bulk are scarce. In this paper, mixtures of hollow silica nanocubes and linear polystyrene in N,-N-dimethylformamide are used to measure the structure factor of the colloidal cubes as a function of non-adsorbing polymer concentration. Together with visual observations these structure factors enabled us to assess the depletion-mediated phase stability of cube-polymer mixtures. The theoretical and experimental phase boundaries for cube-depletant mixtures are in remarkable agreement, despite the simplifications underlying the theory employed.Graphical abstract

Highlights

Ordered structures prepared from functional colloids have multiple applications, and are expected to play an important role in the development of new technologies
The size of the hollow silica nanocubes (HSN) was determined with transmission electron microscopy; representative micrographs are depicted in fig
Demixing of the cubes and polymers was detected from the apparent static structure factor of mixtures of nanocubes and added polymers, in line with theoretical predictions of colloidal cubes upon addition of non-adsorbing polymers

Summary

Introduction

Ordered structures prepared from functional colloids have multiple applications, and are expected to play an important role in the development of new technologies. There are different methods to prepare colloidal solids [3, 4], but most of the available techniques require high particle concentrations or operate under out-of-equilibrium conditions [3,5,6]. Systematic studies on the stability of particles in polymer solutions were first performed by Vincent et al [15,16,17,18], who studied mixtures of latex spheres in aqueous polyethylene oxide (PEO) solutions. The direct link between experiments and theory on the phase stability was pioneered by de Hek and Vrij [19,20], who studied mixtures of silica spheres and polystyrene in cyclohexane

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