Controlling the Organization of Colloidal Sphero-Cylinders Using Confinement in a Minority Phase

• Published in: Gels Vol. 4; no. 1; p. 15
• Main Authors: Hijnen, Niek, Clegg, Paul S
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 02-02-2018; MDPI
• Subjects: capillarity; Carbon; Clusters; colloid; Communication; Cylinders; Percolation; Phase separation; Phase transitions; Polymer blends; Rods; Silicon dioxide; Solvents; wetting; United Kingdom > UK; colloid; wetting; capillarity
• ISSN: 2310-2861; 2310-2861
• DOI: 10.3390/gels4010015

We demonstrate experimentally that a phase-separating host solvent can be used to organize colloidal rods into different cluster and network states. The rods are silica sphero-cylinders which are preferentially wet by the water-rich phase of an oil⁻water binary liquid system. By beginning with the rods dispersed in the single-fluid phase and then varying the temperature to enter the demixed regime, a precisely chosen volume of water-rich phase can be created. We then show how this can be used to create independent clusters of rods, a percolating network, a network of clusters or a system that undergoes hindered phase separation. These different modes are selected by choosing the relative volumes of the rods and the water-rich phase and by the timing of the temperature change.