Search results for " interfaces"
showing 10 items of 1158 documents
Colloidal nanoparticle sorting and ordering on anodic alumina patterned surfaces using templated capillary force assembly
2017
Abstract A new, robust technique of size-selective nanoparticle ordering on porous anodized aluminum oxide (PAAO) templates is presented. Simultaneous particle sorting and array formation is achieved for the first time using a polydisperse suspension of irregularly shaped diamond nanocrystals. The array parameters can be tuned through a balance of evaporation driven particle flux, capillary, electrostatic, and adhesion forces, which are influenced by the asperities of the surface during the capillary and convective assembly dip-coating process. The resulting structures are dense (lower limit approximately 50 nm center separation), isolated (non-touching) nanoparticle arrays with a size dist…
Forces between colloidal particles in aqueous solutions containing monovalent and multivalent ions
2017
The present article provides an overview of the recent progress in the direct force measurements between individual pairs of colloidal particles in aqueous salt solutions. Results obtained by two different techniques are being highlighted, namely with the atomic force microscope (AFM) and optical tweezers. One finds that the classical theory of Derjaguin, Landau, Verwey, and Overbeek (DLVO) represents an accurate description of the force profiles even in the presence of multivalent ions, typically down to distances of few nanometers. However, the corresponding Hamaker constants and diffuse layer potentials must be extracted from the force profiles. At low salt concentrations, double layer f…
Adhesive joining of Aluminum AA6082: the effect of resin and surface treatment
2009
Abstract In this work the effects of both the substrate surface condition and the adhesive properties on single-lap aluminium joint resistance were analysed. The aluminium sheets were mechanically treated with two abrasive surfaces evaluating the induced roughness; four different resins were used in adhesion tests. Moreover, wettability tests were performed in order to evaluate the effect of the above-mentioned parameters on the substrate/adhesive interaction. A design of experiments was defined in order to quantify the effect of the considered factors and their correlation.
Scattering perspectives on nanostructural inhomogeneity in polymer network gels
2017
Abstract Scattering methods based on spatial and temporal contrast fluctuations in polymer-network gels, which originate from polymer-segmental density fluctuations, reveal rich insight into different types and levels of nanostructural inhomogeneity in these soft materials. Complementary contrasting as provided by light, neutron, and X-ray scattering allows such information to be obtained on nano- to micrometer length scales. On top of that, complementary use of static and dynamic scattering methods allows the interplay and effect of these inhomogeneities to be unraveled. This article interrelates a multitude of studies on the application of scattering techniques for analytical assessment o…
PAA-PAMPS Copolymers as an Efficient Tool to Control CaCO3 Scale Formation
2013
Scale formation, the deposition of certain minerals such as CaCO3, MgCO3, and CaSO4 center dot 2H(2)O in industrial facilities and household devices, leads to reduced efficiency or severe damage. Therefore, incrustation is a major problem in everyday life. In recent years, double hydrophilic block copolymers (DHBCs) have been the focus of interest in academia with regard to their antiscaling potential. In this work, we synthesized well-defined blocklike PAA-PAMPS copolymers consisting of acrylic acid (AA) and 2-acrylamido-2-methyl-propane sulfonate (AMPS) units in a one-step reaction by RAFT polymerization. The derived copolymers had dispersities of 1.3 and below. The copolymers have then b…
Calcium Sulfate Nanoparticles with Unusual Dispersibility in Organic Solvents for Transparent Film Processing
2018
Calcium sulfate is one of the most important construction materials. Today it is employed as high-performance compound in medical applications and cement mixtures. We report a synthesis for calcium sulfate nanoparticles with outstanding dispersibility properties in organic solvents without further functionalization. The nanoparticles (amorphous with small γ-anhydrite crystallites, 5–50 nm particle size) form long-term stable dispersions in acetone without any sign of precipitation. 1H NMR spectroscopic techniques and Fourier-transform infrared spectroscopy (FTIR) reveal absorbed 2-propanol on the particle surfaces that induce the unusual dispersibility. Adding water to the nanoparticle disp…
Advances and challenges for experiment and theory for multi-electron multi-proton transfer at electrified solid-liquid interfaces.
2020
Multi-electron, multi-proton transfer is important in a wide spectrum of processes spanning biological, chemical and physical systems. These reactions have attracted significant interest due to both fundamental curiosity and potential applications in energy technology. In this Perspective Review, we shed light on modern aspects of electrode processes in the 21st century, in particular on the recent advances and challenges in multistep electron/proton transfers at solid–liquid interfaces. Ongoing developments of analytical techniques and operando spectrometry at electrode/electrolyte interfaces and reliable computational approaches to simulate complicated interfacial electrochemical reaction…
High power impulse magnetron sputtering of Zn/Al target in an Ar and Ar/O2 atmosphere: The study of sputtering process and AZO films
2019
Financial support provided by Scientific Research Project for Students and Young Researchers Nr. SJZ/2017/4 realised at the Institute of Solid State Physics, University of Latvia is greatly acknowledged.
Synthesis of Au-CdS@CdSe Hybrid Nanoparticles with a Highly Reactive Gold Domain.
2017
We propose a novel route to synthesize semiconductor–gold hybrid nanoparticles directly in water, resulting in much larger gold domains than previous protocols (up to 50 nm) with very reactive surfaces which allow further functionalization. This method advances the possibility of self-assembly into complex structures with catalytic activity toward the reduction of nitro compounds by hydrides. The large size of these gold domains in hybrid particles supports efficient light scattering at the plasmon resonance frequency, making such structures attractive for single-particle studies.
Power ultrasound irradiation during the alkaline etching process of the 2024 aluminium alloy
2015
Abstract Prior to any surface treatment on an aluminum alloy, a surface preparation is necessary. This commonly consists in performing an alkaline etching followed by acid deoxidizing. In this work, the use of power ultrasound irradiation during the etching step on the 2024 aluminum alloy was studied. The etching rate was estimated by weight loss, and the alkaline film formed during the etching step was characterized by glow discharge optical emission spectrometry (GDOES) and scanning electron microscope (SEM). The benefit of power ultrasound during the etching step was confirmed by pitting potential measurement in NaCl solution after a post-treatment (anodizing).