scholarly journals The Influence of Initiator Concentration on Selected Properties of Thermosensitive Poly(Acrylamide-co-2-Acrylamido-2-Methyl-1-Propanesulfonic Acid) Microparticles

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 996
Author(s):  
Agnieszka Gola ◽  
Andrea Bernardi ◽  
Gianfranco Pasut ◽  
Witold Musiał
Keyword(s):  
Light Scattering ◽  
Dynamic Light Scattering ◽  
1H Nmr ◽  
Effect Of Temperature ◽  
Hydrodynamic Diameter ◽  
Aqueous Environment ◽  
Initiator Concentration ◽  
Polymeric Particles ◽  
Temperature Solution ◽  
Dta Curves

Thermosensitive polymers PS1–PS5 were synthesized via the surfactant free precipitation polymerization (SFPP) using 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPSA), and potassium persulfate (KPS) at 70 °C in aqueous environment. The effect of KPS concentrations on particle size and lower critical temperature solution (LCST) was examined by dynamic light scattering (DLS). The conductivity in the course of the synthesis and during cooling were investigated. The structural studies were performed by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), H nuclear magnetic resonance (1H NMR), thermogravimetric analysis (TGA/DTA) and powder X-ray diffraction (PXRD). ATR-FTIR, 1H NMR and PXRD data confirmed the polymeric nature of the material. TGA/DTA curves demonstrated thermal stability up to approx. 160 °C. The effect of temperature on the hydrodynamic diameter (HD) and zeta potential (ZP) were evaluated by dynamic light scattering (DLS) and electrophoretic mobility (EM) in 18–45 °C range. The LCST values were between 30 and 34 °C. HD and polydispersity index (PDI) of aqueous dispersions of the synthesized polymers PS1–PS5 at 18 °C were found to be 226 ± 35 nm (PDI = 0.42 ± 0.04), 299 ± 145 nm (PDI = 0.49 ± 0.29), 389 ± 39 nm (PDI = 0.28 ± 0.07), 584 ± 75 nm (PDI = 0.44 ± 0.06), and 271 ± 50.00 nm (PDI = 0.26 ± 0.14), respectively. At 18 °C the ZPs of synthesized polymers suspensions were −13.14 ± 2.85 mV, −19.52 ± 2.86 mV, −7.73 ± 2.76 mV, −7.99 ± 1.70 mV, and −9.05 ± 2.60 mV for PS1–PS5, respectively. We found that the initiator concentration influences the physicochemical properties of products including the size of polymeric particles and the LCST.

scholarly journals A simple and sensitive sensor for silver ions based on unmodified gold nanoparticles by using dynamic light scattering techniques

2017 ◽  
Vol 95 (12) ◽  
pp. 1267-1272 ◽  
Author(s):  
Zhiyou Xiao ◽  
Anjiang Tang ◽  
Hongsheng Huang ◽  
Ze Wang
Keyword(s):  
Gold Nanoparticles ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
High Sensitivity ◽  
Silver Ions ◽  
Hydrodynamic Diameter ◽  
Optimum Conditions ◽  
Sensitivity And Selectivity ◽  
Sensitive Sensor ◽  
Average Hydrodynamic Diameter

A simple and sensitive assay for Ag+ was developed with unmodified gold nanoparticles (AuNPs) by using dynamic light scattering techniques. Ag+ could induce the oligonucleotide (5′-ATC ACT ATA TCA TAT ACT CAT-3′) to change from a single-stranded structure to a double-stranded structure and desorb from the surface of AuNPs, which triggered the aggregation of AuNPs in the salt solution. The average hydrodynamic diameter of aggregated AuNPs could be detected by using dynamic light scattering techniques. Under the optimum conditions, the average hydrodynamic diameter of AuNPs is proportional to the concentration of Ag+ within the range of 13.3–100.0 nmol/L, with a detection limit of 3.2 nmol/L. The method is easy to operate and has low sample consumption, high sensitivity and selectivity.

scholarly journals COMPLEXATION OF POLYETHYLENE-GLYCOL WITH THE SODIUM SALTS OF CITRIC AND SUCCINIC ACIDS IN THE AQUEOUS SOLUTIONS. STUDIES BY DYNAMIC LIGHT SCATTERING AND UV/VIS SPECTROPHOTOMETRY

2015 ◽  
Vol 11 (8) ◽  
pp. 3866-3872
Author(s):  
E.A. Masimov ◽  
Etibar Hummat Ismailov ◽  
S.Y. Odzhaqverdiyeva
Keyword(s):  
Molecular Weight ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Aqueous Solutions ◽  
Polyethylene Glycols ◽  
Hydrodynamic Diameter ◽  
Absorption Bands ◽  
Sodium Salts ◽  
And Diffusion ◽  
Formation Of Complexes

Dynamic light scattering (DLS) method in combination with the UV/VIS spectrophotometry is used to study the interaction of polyethylene- glycols with a molecular weight  6000 ( PEG6000 ) with sodium salts of citric and succinic acids in aqueous solutions. The values of density, viscosity, refractive and diffusion indexes, the values of the hydrodynamic diameter, wavelength electronic absorption bands for PEG6000 aqueous solutions, their mixtures with succinic and citric acids are determined. It was shown that depending on the composition of the solutions the values of hydrodynamic diameter for aqueous solutions containing 1-5 wt.% PEG6000 and their mixtures with succinic and citric acids (~ 1 wt%) ranges from 3.6 to 5.2 nm. It is assumed that the formation of complexes with the sizes  that are within the above range is due to the features of interaction  and the structure of the complexes formed in solution.

scholarly journals Interior of Amylopectin and Nano-Sized Amylopectin Fragments Probed by Viscometry, Dynamic Light Scattering, and Pyrene Excimer Fluorescence

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2649
Author(s):  
Lu Li ◽  
Jean Duhamel
Keyword(s):  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Free Volume ◽  
Corn Starch ◽  
Structural Features ◽  
Hydrodynamic Diameter ◽  
Similar Amount ◽  
Excimer Fluorescence ◽  
Waxy Corn Starch ◽  
Waxy Corn

Nano-sized amylopectin fragments (NAFs), prepared by extrusion of waxy corn starch, were investigated by viscometry, dynamic light scattering (DLS), and pyrene excimer fluorescence (PEF). NAF57, with a hydrodynamic diameter of 57 nm, was treated with nitric acid to yield three degraded NAFs, which appeared to share the same interior and structural features as amylopectin based on their measured intrinsic viscosity and hydrodynamic diameter. This conclusion was further supported by comparing the efficiency of forming excimer between an excited and a ground-state pyrenyl label covalently attached to the NAFs (Py-NAFs) using their IE/IM ratio of the fluorescence intensity of the excimer (IE) to that of the monomer (IM). The overlapping trends obtained for all Py-NAFs and the pyrene-labeled amylopectin samples by plotting the IE/IM ratio as a function of pyrene content provided further evidence that the interior of NAFs and amylopectin shared the same structural features and contained a similar amount of free volume as predicted by the Solution-Cluster (Sol-CL) model. The presence of free volume was validated by adding linear poly(ethylene glycol) (PEG) chains that could not penetrate the interior of Py-NAFs, thus subjecting the Py-NAFs to increased osmotic pressure, which induced their compression and resulted in an increase in IE/IM.

scholarly journals Characterization of Coliphage PR772 and Evaluation of Its Use for Virus Filter Performance Testing

2004 ◽  
Vol 70 (8) ◽  
pp. 4864-4871 ◽  
Author(s):  
Scott Lute ◽  
Hazel Aranha ◽  
Denise Tremblay ◽  
Dehai Liang ◽  
Hans-W. Ackermann ◽  
...  
Keyword(s):  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Pore Size ◽  
Standardized Test ◽  
Genomic Sequence ◽  
Task Force ◽  
Performance Testing ◽  
Hydrodynamic Diameter ◽  
Filter Performance ◽  
Standardize Nomenclature

ABSTRACT Virus filtration is a key clearance unit operation in the manufacture of recombinant protein, monoclonal antibody, and plasma-derived biopharmaceuticals. Recently, a consensus has developed among filter manufacturers and end users about the desirability of a common nomenclature and a standardized test for classifying and identifying virus-retentive filters. The Parenteral Drug Association virus filter task force has chosen PR772 as the model bacteriophage to standardize nomenclature for large-pore-size virus-retentive filters (filters designed to retain viruses larger than 50 to 60 nm in size). Previously, the coliphage PR772 (Tectiviridae family) has been used in some filtration studies as a surrogate for mammalian viruses of around 50 to 60 nm. In this report, we describe specific properties of PR772 critical to the support of its use for the standardization of virus filters. The complete genomic sequence of virulent phage PR772 was determined. Its genome contains 14,946 bp with an overall G+C content of 48.3 mol%, and 32 open reading frames of at least 40 codons. Comparison of the PR772 nucleotide sequence with the genome of Tectiviridae family prototype phage PRD1 revealed 97.2% identity at the DNA level. By dynamic light-scattering analysis, its hydrodynamic diameter was measured as 82 ± 6 nm, consistent with use in testing large-virus-retentive filters. Finally, dynamic light-scattering analysis of PR772 preparations purified on CsCl gradients showed that the phage preparations are largely monodispersed. In summary, PR772 appears to be an appropriate model bacteriophage for standardization of nomenclature for larger-pore-size virus-retentive filters.

Characterization of Polymeric Particles with Electron Microscopy, Dynamic Light Scattering, and Atomic Force Microscopy

2010 ◽  
Vol 28 (5) ◽  
pp. 472-484 ◽  
Author(s):  
Betina Giehl Zanetti-Ramos ◽  
Mauricia Beddin Fritzen-Garcia ◽  
Tânia Beatriz Creczynski-Pasa ◽  
Cristian Schweitzer De Oliveira ◽  
André Avelino Pasa ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Atomic Force Microscopy ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Force Microscopy ◽  
Atomic Force ◽  
Polymeric Particles

Effect of Adding Electrolyte in Cement Paste on the Dispersing Force of Polycarboxylate-Type Superplasticizer

2009 ◽  
Vol 405-406 ◽  
pp. 160-165
Author(s):  
Jun Ying Lai ◽  
Xiao Qian Qian ◽  
Shu Lin Zhan ◽  
Min Hui Fang
Keyword(s):  
Free Radical ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Cement Paste ◽  
Electrolyte Concentration ◽  
Radical Copolymerization ◽  
Water Soluble ◽  
Hydrodynamic Diameter ◽  
Free Radical Copolymerization ◽  
Poly Ethylene

A series of water-soluble polycarboxylate-type superplasticizer (PCA) were synthesized by free-radical copolymerization of methyl acrylic acid and methoxy poly(ethylene glyco1) monoacrylate macromonomers in water solutions．Micelles were formed from the resultant PCA with predetermined hydrophobic and hydrophilic blocks in water. The hydrodynamic diameter and size distribution of micelles were determined by dynamic light scattering. The change of the concentration of the electrolyte results directly in the variation of the dispersing force of PCA in cement paste. The dispersing force degrades with increasing electrolyte concentration.

scholarly journals Effect of Temperature on 60nm and 100nm Nanosphere Size Standard using Dynamic Light Scattering

2019 ◽  
Vol 9 (2) ◽  
pp. 3284-3286
Keyword(s):  
Particle Size ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Particle Size Analysis ◽  
Polystyrene Latex ◽  
Effect Of Temperature ◽  
Size Analysis ◽  
Measurement Tool ◽  
Scattering Mechanism ◽  
Polystyrene Latex Nanoparticles

It is difficult to use kinetic motion as a measurement tool without temperature affecting the results. In this study, the size of a known nanosphere was used to monitor the effect of temperature towards particle size determination using dynamic light scattering principles. Temperature deviations are always picked up by size measurement using the principle of Brownian motion. The particle size of 60nm and 100nm polystyrene latex nanoparticles in 10mM NaCl solution was measured at four different temperatures set points of 20, 25, 30, 35 and 40°C using dynamic light scattering mechanism. As a result, the size of polystyrene latex nanoparticles was increased with the increases of the temperature. Therefore, for particle size analysis using dynamic light scattering mechanism the temperature of the test must be maintained at 25°C in order to obtain accurate measurement.

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