scholarly journals STUDY OF DILUTED SOLUTIONS OF PORPHYRIN-CONTAINING POLYMERIC SYSTEMS BASED ON POLY-4-VINYLPYRIDINE

2019 ◽  
Vol 62 (8) ◽  
pp. 87-94
Author(s):  
Maria V. Petrova ◽  
Тatiana А. Аgeeva ◽  
Sofia S. Rodina ◽  
Oscar I. Koifman
Keyword(s):  
Light Scattering ◽  
Hydrodynamic Radius ◽  
Scattering Method ◽  
Characteristic Viscosity ◽  
Elastic Light Scattering ◽  
Polymeric Systems ◽  
Dynamic Light Scattering Method ◽  
Increasing Temperature ◽  
Porphyrin Polymers

The dynamic light scattering method was used to determine the diffusion coefficients and hydrodynamic radius of particles in diluted dimethylformamide solutions of poly-4-vinylpyridine, polystyrene, styrene and 4-vinylpyridine copolymers with different comonomer compositions and poly-4-vinylpyridine modified by zinc meso-tetraphenilporphrine. The temperature range was from 20 °C to 25 °C. The copolymers were obtained in different conditions - by thermal and microwave heating.  In order to determine the optimal conditions for the behavior of macromolecular reactions involving these polymers, diluted solutions of all samples were studied by the viscometric method. For these systems, a solvent of appropriate quality was selected, the structure of the solution was studied, the interaction of the solvent with the polymer was evaluated, the parameters of the macromolecular ravel were calculated: characteristic viscosities, Huggin’s constants, root-mean-square distances between the ends of the chains and the specific indicator of the system taking into account the molecular weight of the polymers was presented. It is shown, that the values of characteristic viscosity fall with increasing temperature, the Huggin’s constant, on the contrary increases. These data indicate that the "quality" of the solvent for the systems under study is deteriorating, that is, the tangle of macromolecules in dimethylformamide shrinks with increasing temperature. This behavior is typical for systems with a lower critical temperature of dissolution. The introduction of the porphyrin fragment into the polymer macromolecule loosens the macromolecular coil, but does not change the behavior of the system in the solution as a whole. The results obtained by the quasi-elastic light scattering method are consistent with the data obtained by the viscometric method. The surface morphology and elemental composition of poly-4-vinylpyridine and coordination-related porphyrin polymers on its basis were studied by scanning electron microscopy.

scholarly journals PECULARITIES OF MICELLE FORMATION OF PENTACYCLIC GLYCOSIDES IN AQUEOUS SOLUTIONS

2021 ◽  
Vol 64 (4) ◽  
pp. 26-33
Author(s):  
Natalia V. Mironenko ◽  
Irina V. Shkutina ◽  
Vladimir F. Selemenev
Keyword(s):  
Surface Tension ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Aqueous Solutions ◽  
Hydrodynamic Radius ◽  
Critical Concentration ◽  
Micelle Formation ◽  
Cylindrical Shape ◽  
Scattering Method ◽  
Dynamic Light Scattering Method

The regularities of changes in structural characteristics during the formation of associates in micellar aqueous solutions of triterpene saponins Quillaja Saponin and Sapindus Mukorossi are considered. The dependence of surface tension and adsorption on the concentration of an aqueous saponin solution is analyzed, and the values of surface activity and parameters of the adsorption layer are calculated. The average values of diffusion coefficients for spherical and cylindrical micelles are determined based on the measurement of the solution viscosity. The effect of the electrolyte solution on the surface tension and viscosity of glycoside solutions is studied: when the electrolyte is introduced into the saponin solution, the surface tension decreases, which leads to a shift in the critical concentration of micelle formation towards lower concentrations. The introduction of potassium chloride electrolyte reduces the degree of ionization and, as a result of suppressing the electroviscosity effect, leads to a decrease in the viscosity of the solution. The dynamic light scattering method is used to determine the size of glycoside aggregates. It is established that there are aggregates of several sizes in an aqueous solution of saponin. The size and shape of aggregates were calculated using the concepts of micelle packing parameters. In the region of very low concentrations of glycoside solutions, when approaching the critical concentration of micelle formation in the solution, there are spherical micelles. A further increase in the saponin concentration in the solution leads to a decrease in the content of structures with a hydrodynamic radius of 50-80 nm and the appearance of larger agglomerates with sizes greater than 100 nm. It was found that micelles acquire a less hydrated and more densely packed cylindrical shape in the concentration range of 1.7-2.6 mmol/dm3. Compaction of associates leads to an increase in the content of particles with a hydrodynamic radius of 150-250 nm and larger ones, and their presence predicts the appearance of larger agglomerates. Analyzing the data obtained using the dynamic light scattering method, it can be concluded that aggregates of several sizes co-exist in the volume of aqueous saponin solutions at certain concentrations.

Features of the Aggregation of С70 Fullerene in an o-Xylol Solution Revealed by the Dynamic Light Scattering Method

JETP Letters ◽  
2018 ◽  
Vol 108 (10) ◽  
pp. 680-685
Author(s):  
A. V. Arutyunyan ◽  
E. I. Zavatskii ◽  
V. S. Kozlov ◽  
M. V. Suyasova
Keyword(s):  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Scattering Method ◽  
Dynamic Light Scattering Method

High-throughput dynamic light scattering method for measuring viscosity of concentrated protein solutions

2010 ◽  
Vol 399 (1) ◽  
pp. 141-143 ◽  
Author(s):  
Feng He ◽  
Gerald W. Becker ◽  
Jennifer R. Litowski ◽  
Linda O. Narhi ◽  
David N. Brems ◽  
...  
Keyword(s):  
Light Scattering ◽  
Dynamic Light Scattering ◽  
High Throughput ◽  
Protein Solutions ◽  
Scattering Method ◽  
Dynamic Light Scattering Method

scholarly journals Research of the oils for ship engine by means of dynamic light scattering method

2020 ◽  
pp. 103-108
Author(s):  
Н.Я. Синявский ◽  
И.П. Корнева ◽  
А.М. Иванов ◽  
Н.А. Кострикова
Keyword(s):  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Photon Correlation Spectroscopy ◽  
Correlation Spectroscopy ◽  
Spectroscopy Method ◽  
Engine Oil ◽  
Scattering Method ◽  
Photon Correlation ◽  
Dynamic Light Scattering Method ◽  
Marine Diesel

В данной статье исследована возможность использования метода фотонной корреляционной спектроскопии с целью диагностики судовых двигателей по отработанному моторному маслу для повышения экономичности и безопасности эксплуатации морских судов. Необходимость разработки и внедрения новых эффективных методов диагностики судовых дизелей является актуальной задачей. Целью данной работы явилось исследование ряда свежих и отработанных масел методом динамического рассеяния света для определения изменений, происходящих с маслом в процессе эксплуатации судового дизеля, и выяснения связи этих изменений с неисправностями двигателя. В литературе публикации о подобных исследованиях отсутствуют и результаты, приводимые в настоящей работе, обладают новизной. При исследовании использовался метод фотонной корреляционной спектроскопии для измерения корреляционных функций и последующего получения распределений времен корреляции, коэффициентов диффузии и размеров частиц. Для инверсии преобразования Лапласа применялся метод, основанный на минимизации среднеквадратичного отклонения и регуляризации (RILT), модифицированный для нахождения распределения времен корреляции. Установлено, что распределения гидродинамических радиусов частиц для свежих и отработанных масел существенно различаются. По характеру распределений крупных частиц установлено, что в отработанных маслах понижается уровень агрегации или мицеллообразования полимера модификатора вязкости. Показано, что метод динамического рассеяния света позволяет получать параметры, пригодные для анализа состояния моторного масла и для получения диагностических данных о состоянии двигателя по отработанному маслу. Полученные результаты обладают надежностью, что подтверждается многократной апробацией и общим признанием эффективности метода фотонной корреляционной спектроскопии в разных областях науки. Достоверность полученных результатов подтверждается устойчивостью экспериментов при их многократном повторении, корректностью математической обработки и широкой апробацией используемых методов в мировой практике. Тhe possibility of using the photon correlation spectroscopy method for the purpose of diagnostics of marine engines based on used engine oil to improve the efficiency and safety of operation of marine vessels is investigated in this article. The need to develop and implement new effective methods of diagnostics of marine diesel engines is an actual task. The purpose of this work was to study a number of fresh and used oils by dynamic light scattering method to determine the changes that occur with the oil during the operation of a marine diesel engine, and to find out the connection of these changes with engine failures. There are no publications about such studies in the literature, and the results presented in this paper are new. The photon correlation spectroscopy method was used to measure correlation functions and then obtain distributions of correlation times, diffusion coefficients, and particle sizes. To invert the Laplace transform, we used a method based on minimizing the standard deviation and regularization (RILT), modified to find the correlation time distribution. It was found that the distributions of hydrodynamic radii of particles for fresh and used oils differ significantly. By the character of the distributions of large particles, it was found that the level of aggregation or micelle formation of the polymer of the viscosity modifier decreases in the used oils. It is shown that the dynamic light scattering method allows to obtain parameters suitable for analyzing the state of engine oil and for obtaining diagnostic data on the state of the engine for used oil. The results obtained are reliable, which is confirmed by repeated testing and general recognition of the effectiveness of the photon correlation spectroscopy method in various fields of science. The reliability of the results obtained is confirmed by the stability of experiments when repeated many times, the correctness of mathematical processing and wide approbation of the methods used in the world practice.

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