Preparation and UCST-type phase behavior of glycopolypeptides in alcoholic solvents

RSC Advances ◽  
2015 ◽  
Vol 5 (130) ◽  
pp. 108023-108029 ◽  
Author(s):  
Xi Wang ◽  
Chenglong Ge ◽  
Ying Ling ◽  
Haoyu Tang
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Phase Behavior ◽  
Chain Length ◽  
Main Chain ◽  
Solution Phase ◽  
Side Chain ◽  
Solvent Concentration ◽  
Type Phase ◽  
Chain Composition

Glycopolypeptides with mannose pendants exhibited a reversible UCST-type phase behavior in various alcoholic solvents. The solution phase transition temperature was related to the solvent, concentration, main-chain length, and side-chain composition.

scholarly journals DFT Prediction of Factors Affecting the Structural Characteristics, the Transition Temperature and the Electronic Density of Some New Conjugated Polymers

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1207
Author(s):  
Quoc-Trung Vu ◽  
Thi-Thuy-Duong Tran ◽  
Thuy-Chinh Nguyen ◽  
Thien Vuong Nguyen ◽  
Hien Nguyen ◽  
...  
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Conjugated Polymers ◽  
Bond Length ◽  
Density Functional ◽  
Structural Characteristics ◽  
Side Chain ◽  
Electronic Density ◽  
Energy Field ◽  
Energy Bandgap

Conjugated polymers are promising materials for various cutting-edge technologies, especially for organic conducting materials and in the energy field. In this work, we have synthesized a new conjugated polymer and investigated the effect of distance between bond layers, side-chain functional groups (H, Br, OH, OCH3 and OC2H5) on structural characteristics, phase transition temperature (T), and electrical structure of C13H8OS using Density Functional Theory (DFT). The structural characteristics were determined by the shape, network constant (a, b and c), bond length (C–C, C–H, C–O, C–S, C–Br and O–H), phase transition temperatures, and the total energy (Etot) on a base cell. Our finding shows that the increase of layer thickness (h) of C13H8OS–H has a negligible effect on the transition temperature, while the energy bandgap (Eg) increases from 1.646 eV to 1.675 eV. The calculation of bond length with different side chain groups was carried out for which C13H8OS–H has C–H = 1.09 Å; C13H8OS–Br has C–Br = 1.93 Å; C13H8OS–OH has C–O = 1.36 Å, O–H = 0.78 Å; C13H8OS–OCH3 has C–O = 1.44 Å, O–H =1.10 Å; C13H8OS–OC2H5 has C–O = 1.45 Å, C–C = 1.51Å, C–H = 1.10 Å. The transition temperature (T) for C13H8OS–H was 500 K < T < 562 K; C13H8OS–Br was 442 K < T < 512 K; C13H8OS–OH was 487 K < T < 543 K; C13H8OS–OCH3 was 492 K < T < 558 K; and C13H8OS–OC2H5 was 492 K < T < 572 K. The energy bandgap (Eg) of Br is of Eg = 1.621 eV, the doping of side chain groups H, OH, OCH3, and OC2H5, leads to an increase of Eg from 1.621 eV to 1.646, 1.697, 1.920, and 2.04 eV, respectively.

scholarly journals Percolation Phase Transition from Ionic Liquids to Ionic Liquid Crystals

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Shen Li ◽  
Yanting Wang
Keyword(s):  
Phase Transition ◽  
Ionic Liquid ◽  
Ionic Liquids ◽  
Chain Length ◽  
Complex Fluids ◽  
Dynamics Simulation ◽  
Coarse Grained ◽  
Side Chain ◽  
Side Chains ◽  
Side Chain Length

Abstract Due to their complex molecular structures and interactions, phase behaviors of complex fluids are quite often difficult to be identified by common phase transition analysis methods. Percolation phase transition, on the other hand, only monitors the degree of connection among particles without strict geometric requirements such as translational or orientational order, and thus suitable for pinpointing phase transitions of complex fluids. As typical complex fluids, ionic liquids (ILs) exhibit phases beyond the description of simple liquid theories. In particular, with an intermediate cationic side-chain length, ILs can form the nanoscale segregated liquid (NSL) state, which will eventually transform into the ionic liquid crystal (ILC) structure when the side chains are adequately long. However, the microscopic mechanism of this transformation is still unclear. In this work, by means of coarse-grained molecular dynamics simulation, we show that, with increasing cationic side-chain length, some local pieces of non-polar domains are gradually formed by side chains aligned in parallel inside the NSL phase, before an abrupt percolation phase transition happens when the system transforms into the ILC phase. This work not only identifies that the NSL to ILC phase transition is a critical phenomenon, but also demonstrates the importance of percolation theory to complex fluids.

Elastin-Like Polypeptides as Thermosensitive Polymer System

2014 ◽  
Vol 898 ◽  
pp. 296-299
Author(s):  
Xin Tang
Keyword(s):  
Phase Transition ◽  
Thermal Properties ◽  
Transition Temperature ◽  
Body Temperature ◽  
Chain Length ◽  
Polymer System ◽  
The Body ◽  
Thermosensitive Polymer ◽  
Inverse Transition Cycling ◽  
Inverse Transition

Thermo-responsive elastin-like polypeptides (ELPs) were successfully obtained by inverse transition cycling (ITC) and recursive directional ligation (RDL). Six ELPs displayed thermal properties, depending on their sequence and chain length. It was found that the ELP[KV8F-4 and ELP[KV8F-8 were effective as thermosensitive materials at the body temperature with phase transition temperature from 35 to 45oC.

Effect of Main-Chain Length and Nature of Side Chain on Specific Heat Variations of Polypeptides

1980 ◽  
Vol 13 (4) ◽  
pp. 1020-1021
Author(s):  
Pierre Delhaes ◽  
Jean-Pierre Manceau ◽  
Claudio Toniolo
Keyword(s):  
Specific Heat ◽  
Chain Length ◽  
Main Chain ◽  
Side Chain

Synthesis and Phase Behavior of 4, 4’-Azobisphenol Derivatives

2011 ◽  
Vol 380 ◽  
pp. 316-319
Author(s):  
Sha Sun ◽  
Wen Cai Xu ◽  
Chun Xiu Zhang ◽  
Shi Yong Luo
Keyword(s):  
Phase Transition ◽  
High Temperature ◽  
Transition Temperature ◽  
Phase Behavior ◽  
Phase Transition Temperature ◽  
1H Nmr ◽  
Temperature Reduction ◽  
Polarizing Microscope ◽  
Phase Temperature ◽  
Phase Behaviors

In this paper, 4, 4’-Azobisphenol was synthesized with three methods which were high temperature reduction, Pb-reduction and diazotize-coupling, and diazotize-coupling was the best way. 4, 4’-Azobisphenol derivatives-1, 2- bis(4-(alloxy/hexyloxy)phenyl) diazene were synthesized through etherification. The structures of these compounds were characterized by the methods of 1H-NMR and FTIR. Phase-transition temperature was measured by DSC, and the phase behaviors were studied by the polarizing microscope. In those derivatives, only1, 2- bis(4-(hexyloxy)phenyl) diazene had mesomorphic phase and mosaic texture. Its mesomorphic phase temperature ranged from 89.3°C to101°C.

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