Stereo-chemical contributions to the glass transition and liquid–liquid phase separation in high molecular weight poly(N-vinyl carbazole)

RSC Advances ◽  
2016 ◽  
Vol 6 (35) ◽  
pp. 29326-29333 ◽  
Author(s):  
Abdul G. Al Lafi ◽  
James N. Hay
Keyword(s):  
Molecular Weight ◽  
Glass Transition ◽  
Phase Separation ◽  
Liquid Phase ◽  
High Molecular Weight ◽  
Structural Properties ◽  
Thermal History ◽  
Liquid Phase Separation ◽  
High Molecular Weight Poly ◽  
Liquid Liquid Phase Separation

Thermal history and purification effects on the structural properties of PVK were investigated. Liquid–liquid phase separation is suggested to occur by separation of isotactic rich segments from a matrix which is predominantly atactic.

Interplay of crystallization and liquid–liquid phase separation in polyolefin blends: A thermal history dependence study

Polymer ◽  
2007 ◽  
Vol 48 (14) ◽  
pp. 4226-4234 ◽  
Author(s):  
Katsumi Shimizu ◽  
Howard Wang ◽  
Go Matsuba ◽  
Zhigang Wang ◽  
Hongdoo Kim ◽  
...  
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Thermal History ◽  
Liquid Phase Separation ◽  
History Dependence ◽  
Polyolefin Blends ◽  
Liquid Liquid Phase Separation

scholarly journals Effects of molecular weight and temperature on liquid–liquid phase separation in particles containing organic species and inorganic salts

2015 ◽  
Vol 15 (3) ◽  
pp. 1351-1365 ◽  
Author(s):  
Y. You ◽  
A. K. Bertram
Keyword(s):  
Molecular Weight ◽  
Phase Separation ◽  
Liquid Phase ◽  
Ammonium Sulfate ◽  
Atmospheric Particles ◽  
Liquid Phase Separation ◽  
Organic Species ◽  
Diffusion Rates ◽  
Measured Liquid ◽  
Liquid Liquid Phase Separation

Abstract. Atmospheric particles containing organic species and inorganic salts may undergo liquid–liquid phase separation when the relative humidity varies between high and low values. To better understand the parameters that affect liquid–liquid phase separation in atmospheric particles, we studied the effects of molecular weight and temperature on liquid–liquid phase separation in particles containing one organic species mixed with either ammonium sulfate or ammonium bisulfate. In the molecular-weight-dependent studies, we measured liquid–liquid phase separation relative humidity (SRH) in particles containing ammonium sulfate and organic species with large molecular weights (up to 1153 Da). These results were combined with recent studies of liquid–liquid phase separation in the literature to assess if molecular weight is a useful parameter for predicting SRH. The combined results, which include results from 33 different particle types, illustrate that SRH does not depend strongly on molecular weight (i.e., a clear relationship between molecular weight and SRH was not observed). In the temperature-dependent studies, we measured liquid–liquid phase separation in particles containing ammonium sulfate mixed with 20 different organic species at 244 ± 1 K, 263 ± 1 K, and 278 ± 1 K; a few particles were also studied at 290 ± 1 K. These new results were combined with previous measurements of the same particle types at 290 ± 1 K. The combined SRH data illustrate that for the organic–ammonium sulfate particles studied, the SRH does not depend strongly on temperature. At most the SRH varied by 9.7% as the temperature varied from 290 to 244 K. The high SRH values (> 65%) in these experiments may explain the lack of temperature dependence. Since water is a plasticizer, high relative humidities can lead to high water contents, low viscosities, and high diffusion rates in the particles. For these cases, unless the temperature is very low, liquid–liquid phase separation is not expected to be kinetically inhibited. The occurrence of liquid–liquid phase separation and SRH did depend strongly on temperature over the range of 290–244 K for particles containing α,4-dihydroxy-3-methoxybenzeneacetic acid mixed with ammonium bisulfate. For this particle type, a combination of low temperatures and low water content likely favored kinetic inhabitation of the liquid–liquid phase separation by slow diffusion rates in highly viscous particles. The combined results suggest that liquid–liquid phase separation is likely a common occurrence in atmospheric particles at temperatures from 244–290 K, although particles that do not undergo liquid–liquid phase separation are also likely common.

scholarly journals Effects of molecular weight and temperature on liquid–liquid phase separation in particles containing organic species and ammonium sulfate

2014 ◽  
Vol 14 (16) ◽  
pp. 23341-23373
Author(s):  
Y. You ◽  
A. K. Bertram
Keyword(s):  
Molecular Weight ◽  
Phase Separation ◽  
Liquid Phase ◽  
Relative Humidity ◽  
Ammonium Sulfate ◽  
Atmospheric Particles ◽  
Liquid Phase Separation ◽  
Organic Species ◽  
Measured Liquid ◽  
Liquid Liquid Phase Separation

Abstract. Atmospheric particles containing organic species and inorganic salts may undergo liquid–liquid phase separation when the relative humidity varies between high and low values. To better understand the parameters that affect liquid–liquid phase separation in atmospheric particles, we studied the effects of molecular weight and temperature on liquid–liquid phase separation in particles containing one organic species mixed with ammonium sulfate. In the molecular weight dependent studies, we measured liquid–liquid phase separation relative humidity (SRH) in particles containing ammonium sulfate and organic species with large molecular weights (up to 1153 Da). These results were combined with recent studies of liquid–liquid phase separation in the literature to assess if molecular weight is a useful parameter for predicting SRH. The combined results, which include results from 33 different particle types, illustrate that SRH does not depend strongly on molecular weight (i.e. a clear relationship between molecular weight and SRH was not observed). In the temperature dependent studies, we measured liquid–liquid phase separation in 20 particle types at 244 ± 1 K, 263 ± 1 K, and 278 ± 1 K, as well as 290 ± 1 K for a few of these particle types. These new results were combined with previous measurements of the same particle types at 290 ± 1 K. The combined SRH data illustrate that for the particle types studied the SRH does not depend strongly on temperature. At most the SRH varied by 9.7% as the temperature varied from 290 to 244 K. In addition, for all the particle types studied and at all the temperatures studied, liquid–liquid phase separation was always observed when the O : C < 0.57, frequently observed when 0.57 ≤ O : C < 0.8, and never observed when O : C ≥ 0.8. These combined results suggest that liquid–liquid phase separation is likely a common occurrence in the atmospheric particles at temperatures from 244–290 K. Additional studies at temperatures < 244 K and with other organic species are still needed.

scholarly journals Pulsed electric fields induce modulation of protein liquid–liquid phase separation

Soft Matter ◽  
2020 ◽  
Vol 16 (37) ◽  
pp. 8547-8553
Author(s):  
Mengying Wang ◽  
Sven Falke ◽  
Robin Schubert ◽  
Kristina Lorenzen ◽  
Qing-di Cheng ◽  
...  
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Structural Properties ◽  
Electric Fields ◽  
Growth Kinetics ◽  
Pulsed Electric Fields ◽  
Liquid Phase Separation ◽  
Liquid Liquid Phase Separation

Pulsed electric fields induce modulation of growth kinetics and structural properties of protein liquid dense clusters.

scholarly journals RNA Multimerization as an Organizing Force for Liquid-Liquid Phase Separation

RNA ◽  
2021 ◽  
pp. rna.078999.121
Author(s):  
Philip C Bevilacqua ◽  
Allison M Williams ◽  
Hong-Li Chou ◽  
Sarah Assmann
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Structural Properties ◽  
Compatible Solutes ◽  
Liquid Phase Separation ◽  
Base Pairing ◽  
Condensate Formation ◽  
External Conditions ◽  
Living Organisms ◽  
Liquid Liquid Phase Separation

RNA interactions are exceptionally strong and highly redundant. As such, nearly any two RNAs have the potential to interact with one another over relatively short stretches, especially at high RNA concentrations. This is especially true for pairs of RNAs that do not form strong self-structure. Such phenomenon can drive liquid-liquid phase separation, either solely from RNA-RNA interactions in the presence of divalent or organic cations, or in concert with proteins. RNA interactions can drive multimerization of RNA strands via both base pairing and tertiary interactions. In this article, we explore the tendency of RNA to form stable monomers, dimers, and higher order structures as a function of RNA length and sequence through a focus on the intrinsic thermodynamic, kinetic, and structural properties of RNA. The principles we discuss are independent of any specific type of biomolecular condensate, and thus widely applicable. We also speculate on how external conditions experienced by living organisms can influence formation of nonmembranous compartments, again focusing on the physical and structural properties of RNA. Plants, in particular, are subject to diverse abiotic stresses including extreme temperatures, drought, and salinity. These stresses and the cellular responses to them, including changes in the concentrations of small molecules such as polyamines, salts, and compatible solutes, have the potential to regulate condensate formation by melting or strengthening base pairing. Reversible condensate formation, perhaps including regulation by circadian rhythms, could impact biological processes in plants and other organisms.

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