scholarly journals Molecular Assembly in Block Copolymer-Surfactant Nanoparticle Dispersions: Information on Molecular Exchange and Apparent Solubility from High-Resolution and PFG NMR

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3265
Author(s):  
Guilherme A. Ferreira ◽  
Watson Loh ◽  
Daniel Topgaard ◽  
Olle Söderman ◽  
Lennart Piculell
Keyword(s):  
Block Copolymer ◽  
Aqueous Media ◽  
Particle Surface ◽  
Molecular Assembly ◽  
The Self ◽  
Self Diffusion ◽  
Nanoparticle Dispersions ◽  
Complex Salts ◽  
D Values ◽  
Pfg Nmr

Internally structured block copolymer-surfactant particles are formed when the complex salts of ionic-neutral block copolymers neutralized by surfactant counterions are dispersed in aqueous media. Here, we report the 1H NMR signal intensities and self-diffusion coefficients (D, from pulsed field gradient nuclear magnetic resonance, PFG NMR) of trimethyl alkylammonium surfactant ions and the poly(acrylamide)-block-poly(acrylate) (PAAm-b-PA) polyions forming such particles. The results reveal the presence of an “NMR-invisible” (slowly exchanging) fraction of aggregated surfactant ions in the particle core and an “NMR-visible” fraction consisting of surface surfactant ions in rapid exchange with the surfactant ions dissociated into the aqueous domain. They also confirm that the neutral PAAm blocks are exposed to water at the particle surface, while the PA blocks are buried in the particle core. The self-diffusion of the polyions closely agree with the self-diffusion of a hydrophobic probe molecule solubilized in the particles, showing that essentially all copolymer chains are incorporated in the aggregates. Through centrifugation, we prepared macroscopically phase-separated systems with a phase concentrated in particles separated from a clear dilute phase. D values for the surfactant and block copolymer indicated that the dilute phase contained small aggregates (ca. 5 nm) of surfactant ions and a few anionic-neutral block copolymer chains. Regardless of the overall concentration of the sample, the fraction of block copolymer found in the dilute phase was nearly constant. This indicates that the dilute fraction represented a tail of small particles created by the dispersion process rather than a true thermodynamic solubility of the complex salts.

PFG-NMR Measurements of the Self-Diffusion Coefficients of Water in Equilibrium Poly(HEMA-co-THFMA) Hydrogels

2002 ◽  
Vol 3 (3) ◽  
pp. 554-559 ◽  
Author(s):  
Phuong Y. Ghi ◽  
David J. T. Hill ◽  
Andrew K. Whittaker
Keyword(s):  
Diffusion Coefficients ◽  
The Self ◽  
Self Diffusion ◽  
Pfg Nmr

An Hg2+-selective chemosensor based on the self-assembly of a novel amphiphilic block copolymer bearing rhodamine 6G derivative moieties in purely aqueous media

2015 ◽  
Vol 7 (6) ◽  
pp. 2738-2746 ◽  
Author(s):  
Zhao Wang ◽  
Zhongkui Yang ◽  
Tao Gao ◽  
Jingwen He ◽  
Laijiang Gong ◽  
...  
Keyword(s):  
Block Copolymer ◽  
Self Assembly ◽  
Rhodamine 6G ◽  
Raft Polymerization ◽  
Aqueous Media ◽  
The Self ◽  
Amphiphilic Block Copolymer ◽  
Fluorescent Chemosensor

An amphiphilic block copolymer-based colorimetric and fluorescent chemosensor for Hg2+was prepared, which was synthesized by sequential RAFT polymerization of NIPAM and R6GDM (a novel Hg2+-sensitive rhodamine monomer).

scholarly journals Diffusion Coefficients at Infinite Dilution of Carbon Dioxide and Methane in Water, Ethanol, Cyclohexane, Toluene, Methanol, and Acetone: A PFG-NMR and MD Simulation Study

2021 ◽  
Author(s):  
Daniel Bellaire ◽  
Oliver Großmann ◽  
Kerstin Münnemann ◽  
Hans Hasse
Keyword(s):  
Carbon Dioxide ◽  
Diffusion Coefficient ◽  
Diffusion Coefficients ◽  
Infinite Dilution ◽  
The Self ◽  
Resonance Spectroscopy ◽  
Self Diffusion ◽  
P Diffusion ◽  
Dynamics Simulations ◽  
Pfg Nmr

Diffusion coefficients at infinite dilution are important basic data for all processes involving mass transfer. They can be obtained from studying samplesin equilibrium using nuclear magnetic resonance spectroscopy with pulsed field gradients (PFG-NMR), a technique which is widely used in chemistry but isonly rarely applied in engineering studies. This advantageous technique was employed here to measure the self-diffusion coefficients of diluted solutions ofcarbon dioxide and methane in the pure solvents water, ethanol, cyclohexane, toluene, methanol, and acetone at 298.15 K. For the systems (carbon dioxide +water) and (carbon dioxide + ethanol), measurements were also carried out at 308.15 K, 318.15 K and 333.15 K. Except for (methane + water) and (methane +toluene), no literature data for the methane-containing systems were previously available. At the studied solute concentrations, there is practically no differencebetween the self-diffusion coefficient and the mutual diffusion coefficient. The experimental results are compared to experimental literature data as well as toresults from semi-empirical methods for the prediction of diffusion coefficients at infinite dilution. Furthermore, molecular dynamics simulations were carried outfor all systems to determine the diffusion coefficient at infinite dilution based on force fields that were taken from the literature, and the results are compared tothe experimental data and those from the classical prediction methods.

An Incomplete-Dissociation Model for Diffusion and Ionic Conduction in Pure Molten Salts

1983 ◽  
Vol 38 (5) ◽  
pp. 516-519 ◽  
Author(s):  
A. Klemm
Keyword(s):  
Diffusion Coefficients ◽  
Molten Salts ◽  
Ionic Conduction ◽  
Diatomic Molecules ◽  
The Self ◽  
Degree Of Dissociation ◽  
Self Diffusion ◽  
Internal Mobility ◽  
Dissociation Model ◽  
D Values

Diffusion and ionic conduction in pure 1:1 molten salts is described by an incomplete-disso­ciation model comprising neutral diatomic molecules and monoatomic ions. The internal mobility b+- and the self-diffusion coefficients D+ and D- are given in terms of the six inter­particle friction coefficients and the degree of dissociation. By an approximation it is possible to derive from experimental D+ and D- values an apparent degree of dissociation which ranges from 0.93 for NaCl to 0.51 for TlCl and decreases with temperature.

The self-diffusion of polymethylsilsesquioxane (PMSSO) dendrimers in diluted solutions and melts

Soft Matter ◽  
2020 ◽  
Vol 16 (42) ◽  
pp. 9712-9725
Author(s):  
Konstantin Boldyrev ◽  
Alexander Chernyak ◽  
Ivan Meshkov ◽  
Aziz Muzafarov ◽  
Elena Tatarinova ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Diffusion Coefficients ◽  
The Self ◽  
Self Diffusion ◽  
Pfg Nmr

We investigate the temperature dependence of the self-diffusion coefficients of PMSSO dendrimers by PFG NMR in melts and diluted solutions to reveal the effect of the inner structure of these molecules on their translational dynamics.

Temperature Dependence of the Self-Assembled Styrene Based Random Ionomers in Aqueous Solution

2003 ◽  
Vol 775 ◽  
Author(s):  
Sung-Hwa Oh ◽  
Ju-Myung Song ◽  
Joon-Seop Kim ◽  
Hyang-Rim Oh ◽  
Jeong-A Yu
Keyword(s):  
Partition Coefficients ◽  
Room Temperature ◽  
Aqueous Media ◽  
The Self ◽  
Spectroscopic Methods ◽  
Ion Content ◽  
Repeat Units ◽  
Notable Effect ◽  
Order Of Magnitude ◽  
Experimental Errors

AbstractSolution behaviors of poly(styrene-co-sodium methacrylate) were studied by fluorescence spectroscopic methods using pyrene as a probe. The mol% of methacrylate was in the range 3.6–9.4. Water and N,N-dimethylforamide(DMF) mixture was used as a solvent (DMF/water = 0.2 mol %). The critical micelle (or aggregation) concentrations of ionomers and the partition coefficients of pyrene were obtained the temperature range 10–80°C. At room temperature, the values of CMCs (or CACs) were in the range 4.7 ×10-6 5.3 ×10-6 g/mL and we could not find any notable effect of the content of ionic repeat units within the experimental errors. Unlike CMCs, as the ion content increased, partitioning of pyrene between the hydrophobic aggregates and an aqueous media decreased from 1.5 ×105 to 9.4 ×104. As the temperature increased from 10 to 80 °C, the values of CMCs increased less than one order of magnitude. While, the partition coefficients of pyrene decreased one order of magnitude and the effect of the ion content became negligible.

The Self-Assembly of an Amphiphilic Block Copolymer: A Dissipative Particle Dynamics Study

2005 ◽  
Vol 42 (3) ◽  
pp. 180-183 ◽  
Author(s):  
S. G. Schulz ◽  
U. Frieske ◽  
H. Kuhn ◽  
G. Schmid ◽  
F. Müller ◽  
...  
Keyword(s):  
Block Copolymer ◽  
Self Assembly ◽  
Dissipative Particle Dynamics ◽  
Particle Dynamics ◽  
The Self ◽  
Amphiphilic Block Copolymer

1H NMR characterisation of the diffusional properties of methanogenic granular sludge

1999 ◽  
Vol 39 (7) ◽  
pp. 187-194 ◽  
Author(s):  
P. Lens ◽  
F. Vergeldt ◽  
G. Lettinga ◽  
H. Van As
Keyword(s):  
Diffusion Coefficient ◽  
Relaxation Time ◽  
Bacterial Cell ◽  
Granular Sludge ◽  
T2 Relaxation ◽  
Self Diffusion ◽  
Diffusion Analysis ◽  
S Matrix ◽  
Granular Matrix ◽  
Pfg Nmr

The diffusive properties of mesophilic methanogenic granular sludge have been studied using diffusion analysis by relaxation time separated pulsed field gradient nuclear magnetic resonance (DARTS PFG NMR) spectroscopy. NMR measurements were performed at 22°C with 10 ml granular sludge at a magnetic field strength of 0.5 T (20 MHz resonance frequency for protons). Spin-spin relaxation (T2) time measurements indicate that three 1H populations can be distinguished in methanogenic granular sludge beds, corresponding to water in three different environments. The T2 relaxation time measurements clearly differentiate the extragranular water (T2 ≈ 1000 ms) from the water present in the granular matrix (T2 = 40-100 ms) and bacterial cell associated water (T2 = 10-15 ms). Self-diffusion coefficient measurements at 22°C of the different 1H-water populations as the tracer show that methanogenic granular sludge does not contain one unique diffusion coefficient. The observed distribution of self-diffusion coefficients varies between 1.1 × 10−9 m2/s (bacterial cell associated water) and 2.1 × 10−9 m2/s (matrix associated water).

scholarly journals Self-diffusion scalings in dense granular flows

Soft Matter ◽  
2021 ◽  
Author(s):  
Riccardo Artoni ◽  
Michele Larcher ◽  
James T. Jenkins ◽  
Patrick Richard
Keyword(s):  
Shear Rate ◽  
Solid Fraction ◽  
Granular Flows ◽  
The Self ◽  
Granular Temperature ◽  
Restitution Coefficient ◽  
Self Diffusion ◽  
Diffusivity Tensor ◽  
Dense Granular Flows

The self-diffusivity tensor in homogeneously sheared dense granular flows is anisotropic. We show how its components depend on solid fraction, restitution coefficient, shear rate, and granular temperature.

scholarly journals Self-Diffusion Coefficients, Aggregation Numbers and the Range of Existence of Spherical Micelles of Oxyethylated Alkylphenols

2021 ◽  
Author(s):  
Victor P. Arkhipov ◽  
Natalia A. Kuzina ◽  
Andrei Filippov
Keyword(s):  
Aqueous Solutions ◽  
Diffusion Coefficients ◽  
The Self ◽  
Self Diffusion ◽  
Aggregation Numbers ◽  
Temperature Ranges ◽  
Spherical Micelles ◽  
Limiting Values

AbstractAggregation numbers were calculated based on measurements of the self-diffusion coefficients, the effective hydrodynamic radii of micelles and aggregates of oxyethylated alkylphenols in aqueous solutions. On the assumption that the radii of spherical micelles are equal to the lengths of fully extended neonol molecules, the limiting values of aggregation numbers corresponding to spherically shaped neonol micelles were calculated. The concentration and temperature ranges under which spherical micelles of neonols are formed were determined.

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