Photoinduced depolymerization of poly(olefin sulfone)s possessing photobase generator side-chains: Effect of spacer-chain length

2013 ◽  
Vol 51 (18) ◽  
pp. 3873-3880 ◽  
Author(s):  
Takeo Sasaki ◽  
Takumi Yoneyama ◽  
Shota Hashimoto ◽  
Sumie Takemura ◽  
Yumiko Naka
Keyword(s):  
Chain Length ◽  
Side Chains ◽  
Spacer Chain Length

scholarly journals Effects of Amino Acid Side-Chain Length and Chemical Structure on Anionic Polyglutamic and Polyaspartic Acid Cellulose-Based Polyelectrolyte Brushes

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1789
Author(s):  
Dmitry Tolmachev ◽  
George Mamistvalov ◽  
Natalia Lukasheva ◽  
Sergey Larin ◽  
Mikko Karttunen
Keyword(s):  
Glutamic Acid ◽  
Chain Length ◽  
Chemical Structure ◽  
Side Chain ◽  
Side Chains ◽  
Side Chain Length ◽  
Polyelectrolyte Brushes ◽  
Grafting Density ◽  
The Difference ◽  
Cellulose Surface

We used atomistic molecular dynamics (MD) simulations to study polyelectrolyte brushes based on anionic α,L-glutamic acid and α,L-aspartic acid grafted on cellulose in the presence of divalent CaCl2 salt at different concentrations. The motivation is to search for ways to control properties such as sorption capacity and the structural response of the brush to multivalent salts. For this detailed understanding of the role of side-chain length, the chemical structure and their interplay are required. It was found that in the case of glutamic acid oligomers, the longer side chains facilitate attractive interactions with the cellulose surface, which forces the grafted chains to lie down on the surface. The additional methylene group in the side chain enables side-chain rotation, enhancing this effect. On the other hand, the shorter and more restricted side chains of aspartic acid oligomers prevent attractive interactions to a large degree and push the grafted chains away from the surface. The difference in side-chain length also leads to differences in other properties of the brush in divalent salt solutions. At a low grafting density, the longer side chains of glutamic acid allow the adsorbed cations to be spatially distributed inside the brush resulting in a charge inversion. With an increase in grafting density, the difference in the total charge of the aspartic and glutamine brushes disappears, but new structural features appear. The longer sides allow for ion bridging between the grafted chains and the cellulose surface without a significant change in main-chain conformation. This leads to the brush structure being less sensitive to changes in salt concentration.

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.

Spacer chain length dependence in hydraphile channels

2001 ◽  
Vol 1 (1) ◽  
pp. 23-30 ◽  
Author(s):  
Clare L. Murray ◽  
George W. Gokel
Keyword(s):  
Chain Length ◽  
Length Dependence ◽  
Spacer Chain Length

The effect of spacer chain length on ion binding to bidentate α,ω-diamines: Contrasting ordering for H+and Li+ion affinities

2005 ◽  
pp. 1420-1422 ◽  
Author(s):  
M. Kiran Kumar ◽  
J. Srinivasa Rao ◽  
S. Prabhakar ◽  
M. Vairamani ◽  
G. Narahari Sastry
Keyword(s):  
Chain Length ◽  
Ion Binding ◽  
Li Ion ◽  
Spacer Chain Length

Two-Component Dendritic Gel:  Effect of Spacer Chain Length on the Supramolecular Chiral Assembly

Langmuir ◽  
2004 ◽  
Vol 20 (17) ◽  
pp. 7070-7077 ◽  
Author(s):  
Andrew R. Hirst ◽  
David K. Smith ◽  
Martin C. Feiters ◽  
Huub P. M. Geurts
Keyword(s):  
Chain Length ◽  
Gel Effect ◽  
Two Component ◽  
Spacer Chain Length

scholarly journals Kinetics of Enzyme Attack on Substrates Covalently Attached to Solid Surfaces: Influence of Spacer Chain Length, Immobilized Substrate Surface Concentration and Surface Charge

Langmuir ◽  
2008 ◽  
Vol 24 (20) ◽  
pp. 11762-11769 ◽  
Author(s):  
Joseph Deere ◽  
Rui F. De Oliveira ◽  
Bartłomiej Tomaszewski ◽  
Sarah Millar ◽  
Antonia Lalaouni ◽  
...  
Keyword(s):  
Surface Charge ◽  
Chain Length ◽  
Substrate Surface ◽  
Surface Concentration ◽  
Solid Surfaces ◽  
Spacer Chain Length ◽  
Immobilized Substrate ◽  
Kinetics Of

scholarly journals Effects of Amino Acid Side Chain Length and Chemical Structure on Anionic Polyglutamic and Polyaspartic Acid Cellulose-Based Polyelectrolyte Brushes

2021 ◽  
Author(s):  
Dmitry Tolmachev ◽  
George Mamistvalov ◽  
Natalia Lukasheva ◽  
Sergey Larin ◽  
Mikko Karttunen
Keyword(s):  
Glutamic Acid ◽  
Chain Length ◽  
Chemical Structure ◽  
Side Chain ◽  
Side Chains ◽  
Side Chain Length ◽  
Polyelectrolyte Brushes ◽  
Grafting Density ◽  
The Difference ◽  
Cellulose Surface

We used atomistic molecular dynamics (MD) simulations to study polyelectrolyte brushes based on anionic α-L-glutamic acid and α-L-aspartic acid grafted on cellulose in the presence of divalent CaCl2 salt at different concentrations. The motivation is the search of the ways to control properties such as sorption capacity and the structural response of the brush to multivalent salts. For this detailed understanding of the role of side chain length, chemical structure and their interplay is required. It was found that in the case of glutamic acid oligomers, the longer side chains facilitate attractive interactions with the cellulose surface, which forces the grafted chains to lie down on the surface. The additional methylene group in the side chain enables side chain rotation enhancing this effect. On the other hand, the shorter and more restricted side chains of aspartic acid oligomers prevent attractive interactions to a large degree and push the grafted chains away from the surface. The difference in side chain length also leads to differences in other properties of the brush in divalent salt solutions. At a low grafting density, the longer side chains of glutamic acid allow the adsorbed cations to be spatially distributed inside the brush resulting in a charge inversion. With an increase in grafting density, the difference in the total charge of the aspartic and glutamine brushes disappears, but new structural features appear. The longer sides allow for ion bridging between the grafted chains and the cellulose surface without a significant change in main chain conformation. This leads to the brush structure being less sensitive to changes in salt concentration.

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