Spatial Distribution of Nanocrystals Imaged at the Liquid-Air Interface

Abstract

The 3D distribution of nanocrystals at the liquid-air interface is imaged for the first time on a singleparticle level by cryogenic electron tomography, revealing the equilibrium concentration profile from the interface to the bulk of the liquid. When the surface tension of the liquid is decreased, the interaction of the nanocrystals with the liquid-air interface shifts from adsorption to desorption. Macroscopic surface tension measurements do not detect this transition, due to the presence of surface-active molecular species.

Interactions and Stress Relaxation in Monolayers of Soft Nanoparticles at Fluid-Fluid Interfaces

“…We hypothesize that the faster relaxation process (τ 1 ¼ 6 s) is due to coadsorbed free ligands [26], and that the slow dynamics are attributable to the reconfiguration of the ligands on the nanoparticles. To assess the effect of free ligands we performed control experiments with supernatant fluid obtained by centrifuging the nanoparticles.…”

Understanding the Formation of PbSe Honeycomb Superstructures by Dynamics Simulations

“…A special class of NC superstructures, referred to as NC superlattices, is formed when NC self-assembly is followed by crystal-structure alignment and oriented attachment [74][75][76][77][78][79][80][81][82][83] of close-by NCs, resulting in atomically coherent nanogeometric materials. The formation process of NC superlattices can be confined in 2D when the NCs are adsorbed at a fluid-fluid interface [84]. The NCs selfassemble in ordered monolayers at the fluid-fluid interface, and subsequently perform oriented attachment [73,[85][86][87][88], resulting in 2D atomically coherent nanogeometric materials.…”

Super-resolution microscopy on single particles at fluid interfaces reveals their wetting properties and interfacial deformations

“…40 The contact angle of single particles as small as 10 nm can be determined by FreSCa microscopy. 20,21,41,42 Its complex sample preparation comprises three steps of shock-freezing the fluid interface, exposing the particles upon fracturing the interface, and subsequently coating the colloids with a thin metal layer at a given metal-casting angle, α. FreSCa is well-suited for hydrophobic particles, but not for extremely hydrophilic particles with contact angles lower than the accessible range of metal-casting angles (i.e., θ < α cr , with α cr = 30-45°). 20 Moreover, a threedimensional reconstruction of the interface surrounding the particles is not possible, and, as only part of the particles is visible, θ is extracted through geometrical assumptions on the particle shape.…”