scholarly journals Manuscript-C-dots assembly at interface-041020.pdf

2020 ◽  
Author(s):  
Amin Reza Zolghadr ◽  
Behnam Rostami
Keyword(s):  
Self Assembly ◽  
Carbon Dots ◽  
Sodium Dodecyl ◽  
Surface Region ◽  
Systematic Investigation ◽  
Dynamics Simulation ◽  
Surface Tension Gradient ◽  
Bivariate Analysis ◽  
Air Interface ◽  
Sds Surfactant

We describe a systematic investigation of carbon dots (C-dots) assemblies fabricated at the liquid/air interface because of the surface tension gradient. This gradient is originally created by capillary action and increased by addition of sodium dodecyl sulfate (SDS) surfactant or 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) phospholipid to the surface of C-dots aqueous mixture. The arrangement of carbon dots in liquid bulk phase (before self-assembly) and at the surface region (after self-assembly) was examined by TEM microscopy. The presence of SDS surfactant and POPC phospholipid at the air/water interface induced the C-dots compression. In addition, molecular dynamics simulation was conducted to obtain the structure of C-dots at liquid/vapor interface. The orientation of C-dots is evaluated quantitatively at water/vapor surface by using bivariate analysis.

scholarly journals Manuscript-C-dots assembly at interface-041020.pdf

2020 ◽  
Author(s):  
Amin Reza Zolghadr ◽  
Behnam Rostami
Keyword(s):  
Self Assembly ◽  
Carbon Dots ◽  
Sodium Dodecyl ◽  
Surface Region ◽  
Systematic Investigation ◽  
Dynamics Simulation ◽  
Surface Tension Gradient ◽  
Bivariate Analysis ◽  
Air Interface ◽  
Sds Surfactant

We describe a systematic investigation of carbon dots (C-dots) assemblies fabricated at the liquid/air interface because of the surface tension gradient. This gradient is originally created by capillary action and increased by addition of sodium dodecyl sulfate (SDS) surfactant or 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) phospholipid to the surface of C-dots aqueous mixture. The arrangement of carbon dots in liquid bulk phase (before self-assembly) and at the surface region (after self-assembly) was examined by TEM microscopy. The presence of SDS surfactant and POPC phospholipid at the air/water interface induced the C-dots compression. In addition, molecular dynamics simulation was conducted to obtain the structure of C-dots at liquid/vapor interface. The orientation of C-dots is evaluated quantitatively at water/vapor surface by using bivariate analysis.

scholarly journals Synthesis of Aminated Polystyrene and Its Self-assembly with Nanoparticles at Oil/water Interface

2020 ◽  
Author(s):  
Chenliang Shi ◽  
Yukun Yang ◽  
Ling Lin ◽  
Wenjia Luo ◽  
Maoqing Deng ◽  
...  
Keyword(s):  
Interfacial Tension ◽  
Self Assembly ◽  
Carbon Dots ◽  
Dynamics Simulation ◽  
Functionalized Polymers ◽  
Amino Groups ◽  
Reversible Addition ◽  
Wide Range ◽  
Two Phases ◽  
Short Time

Nanoparticle (NP)–surfactants formed by the self-assembly of NPs and end-functionalized polymers at the hydrophilic/hydrophobic interface have a wide range of applications in many fields. In this study, the influence of density of amino groups, NPs dimension and pH on the interaction between end-functionalized polymers and NPs were extensively investigated. Single amino-terminated polystyrene (PS-NH2, Mw ≈ 0.6k, 2.5k, 3.5k, 3.9k) and diamino-terminated polystyrene (H2N-PS-NH2, Mw ≈ 1.1k, 2.8k) were prepared using reversible addition–fragmentation chain transfer polymerization and atom transfer radical polymerization. NPs with different dimensions (zero-dimensional carbon dots with sulfonate groups, one-dimensional cellulose nanocrystals with sulfate groups and two-dimensional graphene with sulfonate groups) in the aqueous phase were added into the toluene phase containing the aminated PS. The influence of pH and the molecular weight of amino-terminated PS on the interfacial tension between two phases were investigated. The results indicate that aminated PS exhibited the strongest interfacial activity after compounding with sulfonated NPs at a pH of 3. Terminating PS with amino groups on both ends leads to better performance in in reducing the water/toluene interfacial tension than modifying the molecular structure of PS on a single end. The dimension of sulfonated NPs also contributed significantly to the reduction of the water/toluene interfacial tension. The minimal interfacial tension was 4.49 mN/m after compounding PS-NH2 with sulfonated zero-dimensional carbon dots. Molecular dynamics simulation on the evolution of the water/toluene interface in the presence of sulfonated carbon dots and H2N-PS-NH2 revealed that these opposite charged substances moved towards the interface in an extreme short time and orderly assembled in a thermodynamic equilibrium.

scholarly journals Rings, Hexagons, Petals, and Dipolar Moment Sink-Sources: The Fanciful Behavior of Water around Cyclodextrin Complexes

Biomolecules ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 431 ◽  
Author(s):  
Pablo F. Garrido ◽  
Martín Calvelo ◽  
Rebeca Garcia-Fandiño ◽  
Ángel Piñeiro
Keyword(s):  
Degrees Of Freedom ◽  
Driving Forces ◽  
Sodium Dodecyl ◽  
Md Simulations ◽  
Industrial Applications ◽  
Dynamics Simulation ◽  
Supramolecular Complexes ◽  
Conformational Sampling ◽  
Air Interface ◽  
Macromolecular Systems

The basket-like geometry of cyclodextrins (CDs), with a cavity able to host hydrophobic groups, makes these molecules well suited for a large number of fundamental and industrial applications. Most of the established CD-based applications rely on trial and error studies, often ignoring key information at the atomic level that could be employed to design new products and to optimize their use. Computational simulations are well suited to fill this gap, especially in the case of CD systems due to their low number of degrees of freedom compared with typical macromolecular systems. Thus, the design and validation of solid and efficient methods to simulate and analyze CD-based systems is key to contribute to this field. The behavior of supramolecular complexes critically depends on the media where they are embedded, so the detailed characterization of the solvent is required to fully understand these systems. In the present work, we use the inclusion complex formed by two α-CDs and one sodium dodecyl sulfate molecule to test eight different parameterizations of the GROMOS and AMBER force fields, including several methods aimed to increase the conformational sampling in computational molecular dynamics simulation trajectories. The system proved to be extremely sensitive to the employed force field, as well as to the presence of a water/air interface. In agreement with previous experiments and in contrast to the results obtained with AMBER, the analysis of the simulations using GROMOS showed a quick adsorption of the complex to the interface as well as an extremely exotic behavior of the water molecules surrounding the structure both in the bulk aqueous solution and at the water surface. The chirality of the CD molecule seems to play an important role in this behavior. All together, these results are expected to be useful to better understand the behavior of CD-based supramolecular complexes such as adsorption or aggregation driving forces, as well as to introduce new methods able to speed up general MD simulations.

scholarly journals Effect of Deposition Parameters on Electrochemical Properties of Polypyrrole-Graphene Oxide Films

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 624 ◽  
Author(s):  
Alina Iuliana Pruna ◽  
Nelly Ma. Rosas-Laverde ◽  
David Busquets Mataix
Keyword(s):  
Cyclic Voltammetry ◽  
Graphene Oxide ◽  
Electrochemical Properties ◽  
Sodium Dodecyl ◽  
Hybrid Coatings ◽  
Deposition Parameters ◽  
Structure Morphology ◽  
Energy Storage Applications ◽  
Improved Performance ◽  
Sds Surfactant

Graphene oxide (GO)-modified polypyrrole (PPy) coatings were obtained by electrochemical methods in the presence of the anionic surfactant, sodium dodecyl sulfate (SDS). The structure, morphology, and electrochemical properties of the coatings were assessed by Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM) and cyclic voltammetry at varying scan rates, respectively. The properties of the obtained coatings were analyzed with the GO and PPy loadings and electrodeposition mode. The hybrid coatings obtained galvanostatically showed a coarser appearance than those deposited by cyclic voltammetry CV mode and improved performance, respectively, which was further enhanced by GO and PPy loading. The capacitance enhancement can be attributed to the SDS surfactant that well dispersed the GO sheets, thus allowing the use of lower GO content for improved contribution, while the choice of suitable electrodeposition parameters is highly important for improving the applicability of GO-modified PPy coatings in energy storage applications.

scholarly journals Interfacial Crystallization and Supramolecular Self-Assembly of Spider Silk Inspired Protein at the Water-Air Interface

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4239
Author(s):  
Pezhman Mohammadi ◽  
Fabian Zemke ◽  
Wolfgang Wagermaier ◽  
Markus B. Linder
Keyword(s):  
Self Assembly ◽  
Spider Silk ◽  
Assembly Process ◽  
Protein Solution ◽  
Time Resolved ◽  
Macromolecular Assembly ◽  
X Ray Scattering ◽  
Air Interface ◽  
Fundamental Research ◽  
Β Sheet

Macromolecular assembly into complex morphologies and architectural shapes is an area of fundamental research and technological innovation. In this work, we investigate the self-assembly process of recombinantly produced protein inspired by spider silk (spidroin). To elucidate the first steps of the assembly process, we examined highly concentrated and viscous pendant droplets of this protein in air. We show how the protein self-assembles and crystallizes at the water–air interface into a relatively thick and highly elastic skin. Using time-resolved in situ synchrotron X-ray scattering measurements during the drying process, we showed that the skin evolved to contain a high β-sheet amount over time. We also found that β-sheet formation strongly depended on protein concentration and relative humidity. These had a strong influence not only on the amount, but also on the ordering of these structures during the β-sheet formation process. We also showed how the skin around pendant droplets can serve as a reservoir for attaining liquid–liquid phase separation and coacervation from the dilute protein solution. Essentially, this study shows a new assembly route which could be optimized for the synthesis of new materials from a dilute protein solution and determine the properties of the final products.

scholarly journals Synthesis of aminated polystyrene and its self-assembly with nanoparticles at oil/water interface

e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 317-327
Author(s):  
Chenliang Shi ◽  
Ling Lin ◽  
Yukun Yang ◽  
Wenjia Luo ◽  
Maoqing Deng ◽  
...  
Keyword(s):  
Interfacial Tension ◽  
Self Assembly ◽  
Carbon Dots ◽  
Chain Transfer ◽  
Functionalized Polymers ◽  
Amino Groups ◽  
One Dimensional ◽  
Reversible Addition ◽  
Oil Water ◽  
Chain Transfer Polymerization

AbstractThe influence of density of amino groups, nanoparticles dimension and pH on the interaction between end-functionalized polymers and nanoparticles was extensively investigated in this study. PS–NH2 and H2N–PS–NH2 were prepared using reversible addition–fragmentation chain transfer polymerization and atom transfer radical polymerization. Zero-dimensional carbon dots with sulfonate groups, one-dimensional cellulose nanocrystals with sulfate groups and two-dimensional graphene with sulfonate groups in the aqueous phase were added into the toluene phase containing the aminated PS. The results indicate that aminated PS exhibited the strongest interfacial activity after compounding with sulfonated nanoparticles at a pH of 3. PS ended with two amino groups performed better in reducing the water/toluene interfacial tension than PS ended with only one amino group. The dimension of sulfonated nanoparticles also contributed significantly to the reduction in the water/toluene interfacial tension. The minimal interfacial tension was 4.49 mN/m after compounding PS–NH2 with sulfonated zero-dimensional carbon dots.

A New Approach to Fluorescent Chemosensor of Cu2+ Ion

2014 ◽  
Vol 513-517 ◽  
pp. 65-69
Author(s):  
Xiao Jun Hu ◽  
Xin Yan Hu ◽  
Zhi Zhang
Keyword(s):  
Aqueous Solution ◽  
Electron Transfer ◽  
Self Assembly ◽  
Ph Value ◽  
Sodium Dodecyl ◽  
Fluorescence Emission ◽  
Fluorescent Chemosensor ◽  
Dynamic Quenching ◽  
Transfer Effects ◽  
New Approach

According to the principle of dynamic quenching a new ON-OFF fluorescent chemosensor for Cu2+ions was designed, this chemosensor was composed of p-tert-butylthiacalix [arene (TCA),sodium dodecyl sulfate (SDS) and perylene through the form of self-assembly in aqueous solution. Addition of Cu2+ions could result in a quenching of the fluorescence emission of perylene inside micelles, which due to intramicellar complex-fluorophore electron-transfer or energy-transfer effects induced by the complexation of TCA with the Cu2+ions.The experimental results indicated that: Under the condition of TCA/perylene was 800/1, SDS concentration was 150mmol/L and pH value above 9, according to the fluorescence quenching ,within a certain range of the concentration of Cu2+ion can be linearly determined.

Aggregation Behaviours of Surface-Active Ionic Liquids 1-Alkyl-3-methylimidazolium Bis(2-ethylhexyl)sulfosuccinate

2016 ◽  
Vol 69 (11) ◽  
pp. 1254 ◽  
Author(s):  
Jiequn Wu ◽  
Tianxiang Yin ◽  
Shaoxiong Shi ◽  
Weiguo Shen
Keyword(s):  
Ionic Liquids ◽  
Self Assembly ◽  
Alkyl Chain ◽  
Systematic Investigation ◽  
Bulk Solution ◽  
Free Energies ◽  
Imidazolium Cation ◽  
Structure Transition ◽  
Surface Active ◽  
Counter Ion Binding

The systematic investigation of the aggregation behaviours of newly synthesised surface-active ionic liquids 1-alkyl-3-methylimidazolium bis(2-ethylhexyl)sulfosuccinate ([Cnmim][AOT], n = 2, 3, 5, 6, 7) by various techniques is reported. The critical aggregation concentrations (CACs) and the standard Gibbs free energies of aggregation () were determined from measurements on conductivity, fluorescence, and surface tension, which suggested a stronger self-assembly ability in the bulk solution for [Cnmim][AOT] surfactants with longer alkyl chain cations. An interesting structure transition driven by the penetration of the imidazolium cation into the aggregate when n > 4 was found by analysis of the variations of the values of CAC, , the degree of counter ion binding (β), and the micropolarity (I1/I3) immediately after the CAC with changing alkyl chain length of the imidazolium cation, which was further confirmed by 1H NMR measurements.

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