scholarly journals Electron microscopy of nanoparticle superlattice formation at a solid-liquid interface in nonpolar liquids

2020 ◽  
Vol 6 (20) ◽  
pp. eaba1404
Author(s):  
E. Cepeda-Perez ◽  
D. Doblas ◽  
T. Kraus ◽  
N. de Jonge
Keyword(s):  
Electron Microscopy ◽  
Three Dimensional ◽  
Honeycomb Structure ◽  
Liquid Interface ◽  
Thin Layers ◽  
Fine Tuning ◽  
Particle Layer ◽  
Dense Packings ◽  
Solid Liquid Interface ◽  
Solid Liquid

Nanoparticle superlattice films form at the solid-liquid interface and are important for mesoscale materials, but are notoriously difficult to analyze before they are fully dried. Here, the early stages of nanoparticle assembly were studied at solid-liquid interfaces using liquid-phase electron microscopy. Oleylamine-stabilized gold nanoparticles spontaneously formed thin layers on a silicon nitride (SiN) membrane window of the liquid enclosure. Dense packings of hexagonal symmetry were obtained for the first monolayer independent of the nonpolar solvent type. The second layer, however, exhibited geometries ranging from dense packing in a hexagonal honeycomb structure to quasi-crystalline particle arrangements depending on the dielectric constant of the liquid. The complex structures formed by the weaker interactions in the second particle layer were preserved, while the surface remained immersed in liquid. Fine-tuning the properties of the involved materials can thus be used to control the three-dimensional geometry of a superlattice including quasi-crystals.

Experimental and Numerical Analysis of Droplet Cooling

2010 ◽  
Author(s):  
Paolo Tartarini ◽  
Mauro A. Corticelli ◽  
Paolo E. Santangelo
Keyword(s):  
Three Dimensional ◽  
Numerical Approach ◽  
Solid Substrate ◽  
Liquid Interface ◽  
Temperature Trend ◽  
Numerical Code ◽  
Uniform Mesh ◽  
Thermal Transient ◽  
Solid Liquid Interface ◽  
Solid Liquid

Dropwise cooling represents a major subject of interest for both academic and industrial researches. The present work is focused on investigating the thermal transient occurring as two water droplets are gently released (We < 30) onto a heated solid surface. This latter has been kept at initial temperature lower than 373.15 K to analyze the single-phase-evaporation regime. To the purpose, both an experimental and a numerical approach have conveniently been employed. Infrared thermography has been used to evaluate the temperature trend at the solid-liquid interface: an experimental facility has been built to carry out measurements from below, thus realizing a fully non-intrusive approach. A transparent-crystal disk has been inserted to serve as the solid substrate; its upper surface has been painted by a black coating, thus providing a black-body surface as the solid-liquid interface. The infrared thermocamera has been placed below and perpendicular to that surface; temperature has been thereby measured, being emissivity a known parameter. A numerical code has been developed to predict the involved physical phenomena: temperature trend, evaporation time and evaporated flux result from discretizing the three-dimensional energy-diffusion equation by the finite-volume method. Moreover, the model is based on structured non-uniform mesh to adapt to the occurring temperature gradients. Very good agreement is shown between experimental and numerical outcomes in terms of thermal transient and recovery.

Three-dimensional hotspots in evaporating nanoparticle sols for ultrahigh Raman scattering: solid–liquid interface effects

Nanoscale ◽  
2015 ◽  
Vol 7 (15) ◽  
pp. 6619-6626 ◽  
Author(s):  
Yudie Sun ◽  
Zhenzhen Han ◽  
Honglin Liu ◽  
Shengnan He ◽  
Liangbao Yang ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Capillary Force ◽  
Three Dimensional ◽  
Liquid Interface ◽  
Sers Enhancement ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Interface Effects

Decreasing interface adsorbing and increasing capillary-force packing of nanoparticles in an evaporating Ag-sol droplet is responsible for much higher SERS enhancement.

scholarly journals Three-dimensional morphology of bacterial community developed on the index-matched materials

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chigusa Okano ◽  
Kyosuke Takabe ◽  
Tomohiro Hirayama ◽  
Nobuhiko Nomura ◽  
Yutaka Yawata
Keyword(s):  
Structural Model ◽  
Three Dimensional ◽  
Liquid Interface ◽  
Low Contrast ◽  
Promising Tool ◽  
Index Matching ◽  
Transformation Methods ◽  
Solid Liquid Interface ◽  
Biofilm Structure ◽  
Solid Liquid

AbstractHerein, we demonstrate that the use of index-matching materials (IMMs) allows direct visualization of microbial cells maintained at a solid–liquid interface through confocal reflection microscopy (CRM). The refractive index mismatch induces a background reflection at the solid–liquid interface that dwarfs the reflection signals from the cells and results in low-contrast images. We found that the IMMs sufficiently suppressed the background reflection at the solid–liquid interface, facilitating the imaging of microbes at the solid surface using CRM. The use of IMMs allowed quantitative analysis of the morphology of the mesh-like structure of Pseudomonas aeruginosa biofilms formed under denitrifying conditions, which led us to propose a novel structural model of the highly porous biofilm structure. These results indicate that the use of CRM coupled with an IMM offers a unique and promising tool for probing the dynamics of biofilm formation, along with visualization of environmental organisms and newly isolated bacteria, for which transformation methods are difficult to establish.

scholarly journals Nanoscale Mapping of Non-Uniform Heterogeneous Nucleation Kinetics Mediated by Surface Chemistry

2019 ◽  
Author(s):  
Mei Wang ◽  
Thilini Umesha Dissanayake ◽  
Chiwoo Park ◽  
Karen J. Gaskell ◽  
Taylor Woehl
Keyword(s):  
Electron Microscopy ◽  
Liquid Phase ◽  
Surface Chemistry ◽  
Heterogeneous Nucleation ◽  
Liquid Interface ◽  
Nucleation Kinetics ◽  
Nucleation Sites ◽  
Solid Liquid Interface ◽  
Solid Liquid

<p>Nucleation underlies the formation of many liquid-phase synthetic and natural materials with applications in materials chemistry, geochemistry, biophysics, and structural biology. Most liquid-phase nucleation processes are heterogeneous, occurring at specific nucleation sites at a solid-liquid interface; however, the chemical and topographical identity of these nucleation sites and how nucleation kinetics vary from site-to-site remains mysterious. Here we utilize <i>in situ</i> liquid cell electron microscopy to unveil counterintuitive nanoscale non-uniformities in heterogeneous nucleation kinetics on a macroscopically uniform solid-liquid interface. Time-resolved <i>in situ</i> electron microscopy imaging of silver nanoparticle nucleation at a water-silicon nitride interface showed apparently randomly-located nucleation events at the interface. However, nanometric maps of local nucleation kinetics uncovered nanoscale interfacial domains with either slow or rapid nucleation. Interestingly, the interfacial domains vanished at high supersaturation ratio, giving way to rapid spatially uniform nucleation kinetics. Atomic force microscopy and nanoparticle labeling experiments revealed a topographically flat, chemically heterogeneous interface with nanoscale interfacial domains of functional groups similar in size to those observed in the nanometric nucleation maps. These results, along with a semi-quantitative nucleation model, indicate that a chemically non-uniform interface presenting different free energy barriers to heterogeneous nucleation underlies our observations of non-uniform nucleation kinetics. Overall, our results introduce a new imaging modality, nanometric nucleation mapping, and provide important new insights into the impact of surface chemistry on microscopic spatial variations in heterogeneous nucleation kinetics that have not been previously observed.</p>

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