Controlling Bicontinuous Structures through Solvent Segregation Driven Gel
Yuyin Xi, Juscelino Leao, Qiang Ye, Ronald S. Lankone, Li Piin Sung, Yun Liu
The past decade has seen increased research interests in studying bicontinuous structures formed by the colloidal self-assembly due to their many useful applications. A new type of colloidal gel, solvent segregation driven gel (SeedGel), has been recently demonstrated as an effective approach to arrest bicontinuous structures with unique and intriguing properties, such as thermo-reversibility, structural reproducibility and sensitive temperature response. Here, using a model system with silica particles in the 2,6-lutidine/water binary solvent, we investigate the factors controlling the domain size of a SeedGel system by varying particle concentration, solvent ratio, and quenching protocol, as the domain size is closely related to the solvent channel width in a SeedGel. A phase diagram is identified to produce SeedGels for this model system. Our results indicate that by adjusting the sample composition, it is possible to realize bicontinuous domains with well-controlled repeating distance (periodicity). In addition, quenching rate effect on the domain size is systematically investigated showing that it is a very sensitive parameter to control domain size. By further heating SeedGel up into the spinodal region, the structure evolution under high temperatures is also investigated and discussed. These results provide important insights on how to control the bicontinuous structures in SeedGel systems.