scholarly journals Tuning phase transitions of aqueous protein solutions by multivalent cations

2018 ◽  
Vol 20 (42) ◽  
pp. 27214-27225 ◽  
Author(s):  
Olga Matsarskaia ◽  
Felix Roosen-Runge ◽  
Gudrun Lotze ◽  
Johannes Möller ◽  
Alessandro Mariani ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Phase Behaviour ◽  
Protein Solutions ◽  
Salt Solutions ◽  
Ion Radius

Cation-specific characteristics such as ion radius and hydration effects strongly influence the phase behaviour of protein-salt solutions.

scholarly journals Double-Chain Cationic Surfactants: Swelling, Structure, Phase Transitions and Additive Effects

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3946
Author(s):  
Rui A. Gonçalves ◽  
Yeng-Ming Lam ◽  
Björn Lindman
Keyword(s):  
Phase Transitions ◽  
Phase Behaviour ◽  
Double Chain ◽  
Scanning Calorimetry ◽  
Alkyl Chains ◽  
X Ray Scattering ◽  
Amphiphilic Compounds ◽  
Liquid Phases ◽  
Lamellar Phases ◽  
Water Layers

Double-chain amphiphilic compounds, including surfactants and lipids, have broad significance in applications like personal care and biology. A study on the phase structures and their transitions focusing on dioctadecyldimethylammonium chloride (DODAC), used inter alia in hair conditioners, is presented. The phase behaviour is dominated by two bilayer lamellar phases, Lβ and Lα, with “solid” and “melted” alkyl chains, respectively. In particular, the study is focused on the effect of additives of different polarity on the phase transitions and structures. The main techniques used for investigation were differential scanning calorimetry (DSC) and small- and wide-angle X-ray scattering (SAXS and WAXS). From the WAXS reflections, the distance between the alkyl chains in the bilayers was obtained, and from SAXS, the thicknesses of the surfactant and water layers. The Lα phase was found to have a bilayer structure, generally found for most surfactants; a Lβ phase made up of bilayers with considerable chain tilting and interdigitation was also identified. Depending mainly on the polarity of the additives, their effects on the phase stabilities and structure vary. Compounds like urea have no significant effect, while fatty acids and fatty alcohols have significant effects, but which are quite different depending on the nonpolar part. In most cases, Lβ and Lα phases exist over wide composition ranges; certain additives induce transitions to other phases, which include cubic, reversed hexagonal liquid crystals and bicontinuous liquid phases. For a system containing additives, which induce a significant lowering of the Lβ–Lα transition, we identified the possibility of a triggered phase transition via dilution with water.

Features of the phase transitions in aqueous salt solutions of non-stoichiometric polyelectrolyte complexes

1984 ◽  
Vol 26 (8) ◽  
pp. 1872-1880 ◽  
Author(s):  
V.B. Rogacheva ◽  
S.V. Ryzhikov ◽  
A.B. Zezin ◽  
V.A. Kabanov
Keyword(s):  
Phase Transitions ◽  
Salt Solutions ◽  
Polyelectrolyte Complexes ◽  
Aqueous Salt Solutions

Phase Transitions of Ice in Aqueous Salt Solutions within Nanometer-Sized Pores

2019 ◽  
Vol 123 (40) ◽  
pp. 24566-24574 ◽  
Author(s):  
Evelyn Jantsch ◽  
Christian Weinberger ◽  
Michael Tiemann ◽  
Thomas Koop
Keyword(s):  
Phase Transitions ◽  
Salt Solutions ◽  
Aqueous Salt Solutions

scholarly journals Study on the structural phase transitions in NaSICON-type compounds using Ag3Sc2(PO4)3 as a model system

2020 ◽  
Vol 77 (1) ◽  
Author(s):  
Günther J. Redhammer ◽  
Gerold Tippelt ◽  
Quirin Stahl ◽  
Artur Benisek ◽  
Daniel Rettenwander
Keyword(s):  
Phase Transitions ◽  
Structural Phase ◽  
Ionic Conductivities ◽  
Phase Behaviour ◽  
Li Ion Batteries ◽  
Two Phase ◽  
Structured Materials ◽  
Β Phase ◽  
Nasicon Type ◽  
Li Ion

NaSICON (Na Super-Ionic CONducting) structured materials are among the most promising solid electrolytes for Li-ion batteries and `beyond Li-ion' batteries (e.g. Na and K) due to their superior ionic conductivities. Although this material has been well known for decades, its exact phase behaviour is still poorly understood. Herein, a starting material of Na3Sc2(PO4)3 single crystals is used, grown by flux methodology, where Na is subsequently chemically replaced by Ag, in order to take advantage of the higher scattering contrast of Ag. It is found that the NaSICON-type compound shows two phase transitions from a low-temperature monoclinic α-phase to a monoclinic β-phase at about 180 K and to a rhombohedral γ-phase at about 290 K. The framework of [Sc2(PO4)3]3− is rigid and does not change significantly with temperature and change of symmetry. The main driving force for the phase transitions is related to order–disorder phenomena of the conducting cations. The sensitivity of the phase behaviour on the ordering of these ions suggests that small compositional changes can have a great impact on the phase behaviour and, hence, on the ionic conductivity of NaSICON-structured materials.

scholarly journals Modulating the solubility of zwitterionic poly((3-methacrylamidopropyl)ammonioalkane sulfonate)s in water and aqueous salt solutions via the spacer group separating the cationic and the anionic moieties

2016 ◽  
Vol 7 (3) ◽  
pp. 731-740 ◽  
Author(s):  
Viet Hildebrand ◽  
André Laschewsky ◽  
Erik Wischerhoff
Keyword(s):  
Aqueous Phase ◽  
Phase Behaviour ◽  
Salt Solutions ◽  
Spacer Group ◽  
Aqueous Salt Solutions

Even small variations of the spacer group between the anionic and the cationic moieties of poly(sulfobetaine)s strongly affect their aqueous phase behaviour.

scholarly journals Phase Transitions of Binary Lipid Mixtures: A Combined Study by Adiabatic Scanning Calorimetry and Quartz Crystal Microbalance with Dissipation Monitoring

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
P. Losada-Pérez ◽  
N. Mertens ◽  
B. de Medio-Vasconcelos ◽  
E. Slenders ◽  
J. Leys ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Phase Diagrams ◽  
Quartz Crystal Microbalance ◽  
Quartz Crystal ◽  
Phase Behaviour ◽  
Scanning Calorimetry ◽  
Departure Point ◽  
Peltier Element ◽  
Adiabatic Scanning Calorimetry ◽  
Lipid Mixtures

The phase transitions of binary lipid mixtures are studied by a combination of Peltier-element-based adiabatic scanning calorimetry (pASC) and quartz crystal microbalance with dissipation monitoring (QCM-D). pASC, a novel type of calorimeter, provides valuable and unambiguous information on the heat capacity and the enthalpy, whereas QCM-D is proposed as a genuine way of determining phase diagrams by analysing the temperature dependence of the viscosity. Two binary mixtures of phospholipids with the same polar head and differing in the alkyl chain length, DMPC + DPPC and DMPC + DSPC, are discussed. Both techniques give consistent phase diagrams, which compare well with literature results, showing their capability to map the phase behaviour of pure lipids as well as lipid mixtures. This work can be considered as a departure point for further investigations on more complex lipid mixtures displaying relevant phases such as the liquid-ordered phase and solid-lipid interfaces with biologically functional importance.

Interactions and phase transitions in protein solutions

2000 ◽  
Vol 5 (1-2) ◽  
pp. 38-43 ◽  
Author(s):  
Roberto Piazza
Keyword(s):  
Phase Transitions ◽  
Protein Solutions

Phase transitions in hard-core Yukawa fluids: toward a theory of phase stability in protein solutions

2000 ◽  
Vol 12 (8A) ◽  
pp. A437-A442 ◽  
Author(s):  
C Caccamo ◽  
G Pellicane ◽  
D Costa
Keyword(s):  
Phase Transitions ◽  
Phase Stability ◽  
Hard Core ◽  
Protein Solutions

scholarly journals Observation of a re-entrant phase transition in the molecular complex tris(μ2-3,5-diisopropyl-1,2,4-triazolato-κ2N1:N2)trigold(I) under high pressure

IUCrJ ◽  
2016 ◽  
Vol 3 (5) ◽  
pp. 367-376 ◽  
Author(s):  
Christopher H. Woodall ◽  
Jeppe Christensen ◽  
Jonathan M. Skelton ◽  
Lauren E. Hatcher ◽  
Andrew Parlett ◽  
...  
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
Crystal Packing ◽  
Direct Consequence ◽  
Phase Behaviour ◽  
Luminescence Spectroscopy ◽  
Ground State Structure ◽  
X Ray Diffraction ◽  
Complex Behaviour ◽  
Structural Distortions

We report a molecular crystal that exhibits four successive phase transitions under hydrostatic pressure, driven by aurophilic interactions, with the ground-state structure re-emerging at high pressure. The effect of pressure on two polytypes of tris(μ2-3,5-diisopropyl-1,2,4-triazolato-κ2N1:N2)trigold(I) (denoted Form-I and Form-II) has been analysed using luminescence spectroscopy, single-crystal X-ray diffraction and first-principles computation. A unique phase behaviour was observed in Form-I, with a complex sequence of phase transitions between 1 and 3.5 GPa. The ambientC2/cmother cell transforms to aP21/nphase above 1 GPa, followed by aP21/aphase above 2 GPa and a large-volumeC2/csupercell at 2.70 GPa, with the previously observedP21/nphase then reappearing at higher pressure. The observation of crystallographically identical low- and high-pressureP21/nphases makes this a rare example of a re-entrant phase transformation. The phase behaviour has been characterized using detailed crystallographic theory and modelling, and rationalized in terms of molecular structural distortions. The dramatic changes in conformation are correlated with shifts of the luminescence maxima, from a band maximum at 14040 cm−1at 2.40 GPa, decreasing steeply to 13550 cm−1at 3 GPa. A similar study of Form-II displays more conventional crystallographic behaviour, indicating that the complex behaviour observed in Form-I is likely to be a direct consequence of the differences in crystal packing between the two polytypes.

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