Solvent-free confinement of ordered microparticle monolayers: effect of host substrate and pattern symmetry.

The self-organisation of individual suspended colloids into ordered structures that can be mediated by confinement has garnered interest recently. Despite the push for solvent reduction for sustainability reasons, the comprehension and development of solvent-free assembly methods remain largely unaddressed. In this study, we explore the effect of confinement without rigid geometrical constraints, , wall-less confinement on the assembly of monodisperse PMMA powder microspheres (diameters of 3 μm and 10 μm) on fluorocarbon-patterned heterogeneous substrates using a solvent-free rubbing assembly approach.

Toward the Assembly of 2D Tunable Crystal Patterns of Spherical Colloids on a Wafer-Scale.

Entering an era of miniaturization prompted scientists to explore strategies to assemble colloidal crystals for numerous applications, including photonics. However, wet methods are intrinsically less versatile than dry methods, whereas the manual rubbing method of dry powders has been demonstrated only on sticky elastomeric layers, hindering particle transfer in printing applications and applicability in analytical screening. To address this clear impetus of broad applicability, we explore here the assembly on nonelastomeric, rigid substrates by utilizing the manual rubbing method to rapidly (≈20 s) attain monolayers comprising hexagonal closely packed (HCP) crystals of monodisperse dry powder spherical particles with a diameter ranging from 500 nm to 10 μm using a PDMS stamp.

Influence of Wettability and Geometry on Contact Electrification between Nonionic Insulators.

Contact electrification is an interfacial process in which two surfaces exchange electrical charges when they are in contact with one another. Consequently, the surfaces may gain opposite polarity, inducing an electrostatic attraction. Therefore, this principle can be exploited to generate electricity, which has been precisely done in triboelectric nanogenerators (TENGs) over the last decades.