scholarly journals Deposition of Synthetic and Bio-Based Polycations onto Negatively Charged Solid Surfaces: Effect of the Polymer Cationicity, Ionic Strength, and the Addition of an Anionic Surfactant

2020 ◽  
Vol 4 (3) ◽  
pp. 33 ◽  
Author(s):  
María Hernández-Rivas ◽  
Eduardo Guzmán ◽  
Laura Fernández-Peña ◽  
Andrew Akanno ◽  
Andrew Greaves ◽  
...  
Keyword(s):  
Ionic Strength ◽  
Chemical Nature ◽  
Theoretical Calculations ◽  
Polymer Concentration ◽  
Mean Field ◽  
Chemical Properties ◽  
Industrial Applications ◽  
Polymer Chains ◽  
Charged Surfaces ◽  
Adsorbed Polymer

The deposition of layers of different polycations (synthetic or derived from natural, renewable resources) onto oppositely charged surfaces has been studied using ellipsometry and quartz crystal microbalance with dissipation monitoring (QCM-D). Information about the thickness of the deposited layers and their water content was ascertained. The adsorption of the different polycations onto negatively charged surfaces was found to be a complex process, which is influenced by the chemical nature of the polymer chains, ionic strength, polymer concentration and the addition of additives such as surfactants. The experimental picture shows a good agreement with theoretical calculations performed using the Self-Consistent Mean Field (SCF) approach. The results show that the electrostatically-driven deposition can be tuned by modifying the physico-chemical properties of the solutions and the chemical nature of the adsorbed polymer. This versatile approach is a big step forward in aiding the design of new polymers for many industrial applications and, in particular, the design of sustainable washing formulations for cosmetic applications.

Isatin: A Scaffold with Innumerable Biodiversity

2020 ◽  
Vol 20 ◽  
Author(s):  
Priyobrata Nath ◽  
Agnish Mukherjee ◽  
Sougata Mukherjee ◽  
Sabyasachi Banerjee ◽  
Samarpita Das ◽  
...  
Keyword(s):  
Biological Effects ◽  
Scientific Information ◽  
Research Work ◽  
Chemical Properties ◽  
Industrial Applications ◽  
Biologically Relevant ◽  
Extensive Information ◽  
Relevant Compound ◽  
A Minor ◽  
Clinical Conditions

: Isatin is an endogenous and a significant category of fused heterocyclic component, widely been a part of several potential biologically useful synthetics. Since its discovery, tons of research work has been conducted with respect to the synthesis, chemical properties, and biological and industrial applications. It contains indole nucleus having both lactam and keto moiety which while being a part of a molecular framework exerted several biological effects, viz.; antimicrobial, antitubercular, anticonvulsant, anticancer etc. Isatin derivatives are synthetically significant substrates, which can be utilized for the synthesis of huge diversified chemical entities of which few members emerged to be a drug. The reason for this review is to provide extensive information pertaining to the chemistry and its significance in altering several pathological states of isatin and its derivatives. A Structure Activity Relationships study thus developed through a gamut of scientific information indicates the importance of mostly electron withdrawing groups, halogens, nitro, alkoxy and to a minor extent groups with positive inductive effects, such as methyl at position 1, 5, 6 and 7 of isatin in alleviating several clinical conditions. It is also observed from the survey that the presence of two oxo groups at position 2 and 3 sometimes become insignificant as fusion with a heterocycle at those position resulted in a biologically relevant compound.

scholarly journals Effect of Bjerrum pairs on electrostatic properties in an electrolyte solution near charged surfaces: A mean-field approach

2021 ◽  
Author(s):  
Jun-Sik Sin
Keyword(s):  
Electrolyte Solution ◽  
Size Effects ◽  
Mean Field ◽  
Finite Size ◽  
Ion Association ◽  
Finite Size Effects ◽  
Field Approach ◽  
Electrostatic Properties ◽  
Charged Surfaces ◽  
Orientational Ordering

In this paper, we investigate the consequences of ion association, coupled with the considerations of finite size effects and orientational ordering of Bjerrum pairs as well as ions and water...

scholarly journals RuSseL: A Self-Consistent Field Theory Code for Inhomogeneous Polymer Interphases

Computation ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 57
Author(s):  
Constantinos J. Revelas ◽  
Aristotelis P. Sgouros ◽  
Apostolos T. Lakkas ◽  
Doros N. Theodorou
Keyword(s):  
Field Theory ◽  
Polymer Melt ◽  
Polymer Chains ◽  
Solid Polymer ◽  
One Dimensional ◽  
Consistent Field ◽  
Adsorbed Polymer ◽  
Self Consistent ◽  
Self Consistent Field ◽  
Self Consistent Field Theory

In this article, we publish the one-dimensional version of our in-house code, RuSseL, which has been developed to address polymeric interfaces through Self-Consistent Field calculations. RuSseL can be used for a wide variety of systems in planar and spherical geometries, such as free films, cavities, adsorbed polymer films, polymer-grafted surfaces, and nanoparticles in melt and vacuum phases. The code includes a wide variety of functional potentials for the description of solid–polymer interactions, allowing the user to tune the density profiles and the degree of wetting by the polymer melt. Based on the solution of the Edwards diffusion equation, the equilibrium structural properties and thermodynamics of polymer melts in contact with solid or gas surfaces can be described. We have extended the formulation of Schmid to investigate systems comprising polymer chains, which are chemically grafted on the solid surfaces. We present important details concerning the iterative scheme required to equilibrate the self-consistent field and provide a thorough description of the code. This article will serve as a technical reference for our works addressing one-dimensional polymer interphases with Self-Consistent Field theory. It has been prepared as a guide to anyone who wishes to reproduce our calculations. To this end, we discuss the current possibilities of the code, its performance, and some thoughts for future extensions.

Micro-Ribbons and Micro-Wires Silica Synthesis Using Bottom-Top Technique

2020 ◽  
Vol 1008 ◽  
pp. 33-38
Author(s):  
Marwa Nabil ◽  
Hussien A. Motaweh
Keyword(s):  
Selection Process ◽  
Chemical Properties ◽  
Industrial Applications ◽  
Preparation Process ◽  
Pure Silica ◽  
One Step ◽  
Materials Used ◽  
Sonication Technique ◽  
Silica Synthesis ◽  
Physical And Chemical

Silica is one of the most important materials used in many industries. The basic factor on which the selection process depends is the structural form, which is dependent on the various physical and chemical properties. One of the common methods in preparing pure silica is that it needs more than one stage to ensure the preparation process completion. The goal of this research is studying the nucleation technique (Bottom-top) for micro-wires and micro-ribbons silica synthesis. The silica nanoand microstructures are prepared using a duality (one step); a combination of alkali chemical etching process {potassium hydroxide (3 wt %) and n-propanol (30 Vol %)} and the ultra-sonication technique. In addition, the used materials in the preparation process are environmentally friendly materials that produce no harmful residues. The powder product is characterized using XRD, FTIR, Raman spectrum and SEM for determining the shape of architectures. The most significant factor of the nucleation mechanism is the sonication time of silica powder production during the dual technique. The product stages are as follows; silica nanoparticles (21-38 nm), nanoclusters silica (46 – 67 nm), micro-wires silica (1.17 – 6.29 μm), and micro-ribbons silica (19.4 – 54.1 μm). It's allowing for use in environmental applications (multiple wastewater purification, multiple uses in air filters, as well as many industrial applications).

Shear-induced stretching of adsorbed polymer chains

Soft Matter ◽  
2009 ◽  
Vol 5 (16) ◽  
pp. 3014 ◽  
Author(s):  
Gui-Li He ◽  
René Messina ◽  
Hartmut Löwen ◽  
Anton Kiriy ◽  
Vera Bocharova ◽  
...  
Keyword(s):  
Polymer Chains ◽  
Adsorbed Polymer

Diffusion and Migration of Ions in Sedimentary Rock Matrix: Effects of Ionic Strength and Tracer Concentration on Diffusion of Cs+ ions in Sandstone

2003 ◽  
Vol 807 ◽  
Author(s):  
Haruo Sato
Keyword(s):  
Ionic Strength ◽  
Matrix Effects ◽  
Chemical Properties ◽  
Effective Diffusivity ◽  
Concentration Profiles ◽  
Tracer Concentration ◽  
And Migration ◽  
Physical And Chemical ◽  
Cs Ions ◽  
And Chemical Properties

ABSTRACTIn-diffusion experiments for Cs+ and I− in sandstone were performed as a function of ionic strength ([NaCl]=0.01, 0.51M) and tracer concentration ([CsI]=7.5E-5, 1.5E-2M) together with the measurements of the physical and chemical properties of sandstone, and apparent diffusivities (Da) for Cs+ were obtained. The obtained Da-values for Cs+ scarcely depended on [NaCl], but increased with increasing [Cs+]. This trend is consistent with that of rock capacity factors (α), indicating that distribution coefficient (Kd) onto sandstone and effective diffusivity scarcely depend on [NaCl]. The concentration profiles of I− were all in already breakthrough. Although this indicates that I− diffusion is faster than that of Cs+, the concentration profiles of I− may have been lower than those for blank samples, judging synthetically from the correlations between α-values and the concentration profiles of Cs+ and from the concentration profiles of I− in the blank samples. Finally, the effects of [Cs+] and[NaCl] on Kd/-values for Cs+ were discussed from the viewpoint of adsorption by ion exchange and electrostatic attraction. The kd-values were considered to be combined sorption by both reactions.

Conformational behavior of short adsorbed polymer chains

1999 ◽  
Vol 35 (1) ◽  
pp. 167-172 ◽  
Author(s):  
Linxi Zhang ◽  
Xianghong Wang ◽  
Haizhu Ma ◽  
Youxing Huang
Keyword(s):  
Polymer Chains ◽  
Conformational Behavior ◽  
Adsorbed Polymer

Synthesis, Characterization, Applications, and Toxicity of Green Synthesized Nanoparticles

2021 ◽  
Vol 22 ◽  
Author(s):  
João Marcos Pereira Galúcio ◽  
Sorrel Godinho Barbosa de Souza ◽  
Arthur Abinader Vasconcelos ◽  
Alan Kelbis Oliveira Lima ◽  
Kauê Santana da Costa ◽  
...  
Keyword(s):  
Green Synthesis ◽  
Low Cost ◽  
Chemical Properties ◽  
Analytical Techniques ◽  
Industrial Applications ◽  
Synthesis Methods ◽  
Methods Of Synthesis ◽  
Food Applications ◽  
Living Organisms ◽  
Harmful Effects

: Nanotechnology is a cutting-edge area with numerous industrial applications. Nanoparticles are structures that have dimensions ranging from 1–100 nm which exhibit significantly different mechanical, optical, electrical, and chemical properties when compared with their larger counterparts. Synthetic routes that use natural sources, such as plant extracts, honey, and microorganisms are environmentally friendly and low-cost methods that can be used to obtain nanoparticles. These methods of synthesis generate products that are more stable and less toxic than those obtained using conventional methods. Nanoparticles formed by titanium dioxide, zinc oxide, silver, gold, and copper, as well as cellulose nanocrystals are among the nanostructures obtained by green synthesis that have shown interesting applications in several technological industries. Several analytical techniques have also been used to analyze the size, morphology, hydrodynamics, diameter, and chemical functional groups involved in the stabilization of the nanoparticles as well as to quantify and evaluate their formation. Despite their pharmaceutical, biotechnological, cosmetic, and food applications, studies have detected their harmful effects on human health and the environment; and thus, caution must be taken in uses involving living organisms. The present review aims to present an overview of the applications, the structural properties, and the green synthesis methods that are used to obtain nanoparticles, and special attention is given to those obtained from metal ions. The review also presents the analytical methods used to analyze, quantify, and characterize these nanostructures.

Effect of Acid–Base Interactions on Conformation of Adsorbed Polymer Chains

2015 ◽  
Vol 5 (1) ◽  
pp. 45-49 ◽  
Author(s):  
He Zhu ◽  
Nishad Dhopatkar ◽  
Ali Dhinojwala
Keyword(s):  
Polymer Chains ◽  
Acid Base ◽  
Adsorbed Polymer
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