Pickering Emulsions: Role of Particle Wettability and Adhesive Force on Droplet Bridging.

This study demonstrates the engineering of bridged Pickering emulsion (PE) gels by tuning the particle position at the interface and adhesive forces. This is achieved through controlled surface modification of hematite particles using oleic acid in a water-decane system. Microscopy observations revealed that the droplets are stabilized through a bridging mechanism, where oil droplets are connected by a shared monolayer of particles, with an intervening water layer between them.

Polymer-Mediated Crack Suppression in Deposit of Nanoellipsoids.

Uniform distribution of particles and crack suppression in dried particulate deposits are major challenges for applications in coating and printing technologies. To address this, we investigated the impact of the addition of a water-soluble polymer, poly(vinyl alcohol) (PVA), on the evaporative self-assembly and kinetics of crack formation in deposits of anisotropic colloids. The fluid flow inside the drying drop is significantly altered due to polymer-mediated adsorption of ellipsoids to the drop surface.

Investigating the optical and electrical performance of rod coated silver nanowire-based transparent conducting films.

Silver nanowires (Ag NWs) are highly promising building blocks for developing transparent conducting films (TCFs) due to their high electrical conductivity and good optical transparency. The large-scale production of Ag NW-based high-quality TCFs using low-cost processing methods can replace the traditional oxide based TCFs. Therefore, developing a reliable technique for large-scale fabrication of Ag NW-based TCFs is vital.

Association in Like-Charged Surfactant-Nanoparticle Systems: Interfacial and Bulk Effects.

The association of similarly charged surfactant molecules and nanoparticles in an aqueous solution remains unresolved, and the understandings reported in the literature are conflicting. To address this issue, we undertake a fundamental study to investigate bulk and interfacial phenomena in binary mixtures of (i) positively charged nanoparticles and cationic surfactants and (ii) negatively charged nanoparticles and anionic surfactants. We find that the surfactant molecules adsorb on the surface of the nanoparticle despite similar charge, leading to supercharging of particles and simultaneously driving more surfactant molecules to the air-dispersion interface.

Soft colloidal monolayers with reflection symmetry through confined drying.

Colloidal monolayers serve as fundamental building blocks in fabricating diverse functional materials, pivotal for surface modifications, chemical reactivity, and controlled assembly of nanoparticles. In this article, we report the formation of colloidal monolayers generated by drying an aqueous droplet containing soft colloids confined between two hydrophilic parallel plates. The analysis of the kinetics of evaporation in this confined mode showed that: (i) for a significant portion of the drying time, the drops adopt a catenoid configuration; (ii) in the penultimate stage of drying, the catenoid structure undergoes division into two daughter droplets; (iii) the three-phase contact line remains pinned at a specific location while it continuously slips at all other locations.