The Control of Colloidal Grain Boundaries through Evaporative Vertical Self‐Assembly

Abstract

Self‐assembly continuously gains attention as an excellent method to create novel nanoscale structures with a wide range of applications in photonics, optoelectronics, biomedical engineering, and heat transfer applications. However, self‐assembly is governed by a diversity of complex interparticle forces that cause fabricating defectless large scale (>1 cm) colloidal crystals, or opals, to be a daunting challenge. Despite numerous efforts to find an optimal method that offers the perfect colloidal crystal by minimizing defects, it has been difficult to provide physical interpretations that govern the development of defects such as grain boundaries. This study reports the control over grain domains and intentional defect characteristics that develop during evaporative vertical deposition. The degree of particle crystallinity and evaporation conditions is shown to govern the grain domain characteristics, such as shapes and sizes. In particular, the grains fabricated with 300 and 600 nm sphere diameters can be tuned into single‐column structures exceeding ≈1 mm by elevating heating temperature up to 93 °C. The understanding of self‐assembly physics presented in this work will enable the fabrication of novel self‐assembled structures with high periodicity and offer fundamental groundworks for developing large‐scale crack‐free structures.

Temperature-dependent mechanical behavior of three-dimensionally ordered macroporous tungsten

“…However, in this method, the tensile forces generated during water evaporation caused longitudinal cracks in the PMMA film. In addition, transverse cracks occurred at the boundaries of wet and dry regimes as the water evaporated [35,36,37]. Therefore, the PMMA films produced by convective selfassembly formed strips with lengths around 0.5 cm, widths around 0.2 cm, and thicknesses less than 50 μm (Fig.…”

“…The different degrees of order in the 3DOM structures were attributed to the different preparation methods of the PMMA templates. The convective self-assembly method can generate much thinner layers of packed PMMA spheres with uniform thickness compared to the sedimentation method [34,35]. The thinner PMMA template contains fewer mispacked PMMA spheres, and it is more controllable during the infiltration of precursor, which avoids over-or insufficient infiltration.…”

Colloidal Crystal Thin Films with Square Lattice Nanoprotrusions Formed by Self‐Assembly via Spin‐Coating and Heating

“…However, they have the disadvantage of elongated time consumption and are not suitable for forming colloidal crystal thin films. Alternative methods suitable for forming colloidal crystal thin films are the vertical immersion [19] or spin coating method, [20] which uses the capillary force during solvent volatilization. In these methods, the colloids are usually arranged in a hexagonal lattice in a plane parallel to the substrate surface, such as a two-dimensional (2D) close-packed structure or face-centered cubic (fcc) structures.…”

Molecular Dynamics Investigation of Liquid and Vapor Interactions Near an Evaporating Interface: A Theoretical Genetics Perspective

“…In modern engineering, there have been numerous efforts to develop thermal management devices that facilitate evaporation or condensation phase transition processes by installing nanostructures. [8][9][10][11][12] Despite the significance of the phase transition process in many applications that have implemented nanostructures, it has been challenging to completely understand nanoscale phase transition process at the molecular level.…”