scholarly journals Side-chain tuning in conjugated polymer photocatalysts for improved hydrogen production from water

2020 ◽  
Vol 13 (6) ◽  
pp. 1843-1855 ◽  
Author(s):  
Duncan J. Woods ◽  
Sam A. J. Hillman ◽  
Drew Pearce ◽  
Liam Wilbraham ◽  
Lucas Q. Flagg ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Conjugated Polymer ◽  
Chemical Structure ◽  
Side Chain ◽  
Side Chains ◽  
Structure Property ◽  
Polymer Backbone ◽  
Solution Processable

Structure–property–activity relationships in solution processable polymer photocatalysts for hydrogen production from water were probed by varying the chemical structure of both the polymer side-chains and the polymer backbone.

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.

Study on Preparation and Dispersion Effect of Polycarboxylate Superplasticizer with Broken Dentiform Structure

2011 ◽  
Vol 250-253 ◽  
pp. 984-989 ◽  
Author(s):  
Zhi Yong Liu ◽  
Chong Cui ◽  
Li Li
Keyword(s):  
Carboxylic Acid ◽  
Chemical Structure ◽  
Side Chain ◽  
Side Chains ◽  
Test Results ◽  
Dispersion Effect ◽  
Anionic Polymer ◽  
Short Side ◽  
Carboxylic Acid Groups ◽  
Radical Polymerisation

Based on the analysis of the chemical structure of polycarboxylate-type SPs grafted PEO side chains, as well as sulfonic and carboxylic acid groups, a kind of polycarboxylate-based SPs grafted varied PEO side chains were synthesized by using radical polymerisation techniques.The relative dispersing effectiveness of the SPs was evaluated in cement paste and concrete by measuring paste flow and concrete slumps. The test results indicat that the copolymers with shorter PEO side chains (with 9 and 14 EO units) give lower initial dispersing power but higher time retention,with the prolonging of PEO side chains the higher initial dispersing effect and the lower time retention can be received. The excellent dispersing property and time retention of synthesized SPs for cementious systems can be achieved by grafted long side chain(with 45 EO units) integrated with short side chain(9 or 14 EO) at the backbone of anionic polymer.

scholarly journals Variation of the Side Chain Branch Position Leads to Vastly Improved Molecular Weight and OPV Performance in 4,8-dialkoxybenzo[1,2-b:4,5-b′]dithiophene/2,1,3-benzothiadiazole Copolymers

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Robert C. Coffin ◽  
Christopher M. MacNeill ◽  
Eric D. Peterson ◽  
Jeremy W. Ward ◽  
Jack W. Owen ◽  
...  
Keyword(s):  
Thin Film ◽  
Molecular Weight ◽  
Thin Film Transistor ◽  
Power Conversion ◽  
Hole Mobility ◽  
Side Chain ◽  
Side Chains ◽  
Absorption Profile ◽  
Polymer Backbone ◽  
Chain Branch

Through manipulation of the solubilizing side chains, we were able to dramatically improve the molecular weight(Mw)of 4,8-dialkoxybenzo[1,2-b:4,5-b′]dithiophene (BDT)/2,1,3-benzothiadiazole (BT) copolymers. When dodecyl side chains (P1) are employed at the 4- and 8-positions of the BDT unit, we obtain a chloroform-soluble copolymer fraction withMwof 6.3 kg/mol. Surprisingly, by moving to the commonly employed 2-ethylhexyl branch (P2),Mwdecreases to 3.4 kg/mol. This is despite numerous reports that this side chain increases solubility andMw. By moving the ethyl branch in one position relative to the polymer backbone (1-ethylhexyl,P3),Mwis dramatically increased to 68.8 kg/mol. As a result of thisMwincrease, the shape of the absorption profile is dramatically altered, withλmax= 637 nm compared with 598 nm forP1and 579 nm forP2. The hole mobility as determined by thin film transistor (TFT) measurements is improved from~1×10−6 cm2/Vs forP1andP2to7×10−4 cm2/Vs forP3, while solar cell power conversion efficiency in increased to2.91%forP3relative to0.31%and0.19%forP1andP2, respectively.

Mechanically strong, fluorescent hydrogels from zwitterionic, fully π-conjugated polymers

2014 ◽  
Vol 50 (64) ◽  
pp. 8930-8933 ◽  
Author(s):  
Einat Elmalem ◽  
Frank Biedermann ◽  
Maik R. J. Scherer ◽  
Alexandros Koutsioubas ◽  
Chris Toprakcioglu ◽  
...  
Keyword(s):  
Conjugated Polymers ◽  
Conjugated Polymer ◽  
Side Chains ◽  
Polymer Backbone

Mechanically strong supramolecular hydrogels can be obtained by combining a rigid, fully π-conjugated polymer backbone and zwitterionic side chains.

Impact of the alkyl side chain position on the photovoltaic properties of solution-processable organic molecule donor materials

2016 ◽  
Vol 4 (30) ◽  
pp. 11747-11753 ◽  
Author(s):  
J. Zhang ◽  
X. W. Zhu ◽  
C. He ◽  
H. J. Bin ◽  
L. W. Xue ◽  
...  
Keyword(s):  
Organic Molecule ◽  
Side Chain ◽  
Side Chains ◽  
Alkyl Side Chain ◽  
Photovoltaic Properties ◽  
Alkyl Side Chains ◽  
Solution Processable ◽  
New Compounds

Two new compounds with alkyl side chains at different positions have a similar structure, but exhibit different photovoltaic properties.

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.

The chiral smectic H liquid crystalline structure of a comb-shaped side-chain polymer

1992 ◽  
Vol 50 (1) ◽  
pp. 272-273
Author(s):  
L.S. Li ◽  
S. I. Stupp
Keyword(s):  
Crystalline Structure ◽  
Chemical Structure ◽  
Liquid Crystalline ◽  
Nitrile Group ◽  
Chiral Center ◽  
Side Chain ◽  
Side Chains ◽  
Chain Polymer ◽  
Liquid Crystalline Structure ◽  
Aliphatic Spacer

The polymer investigated is a comb-shaped polymer with long oligomeric side chains containing a chiral center. The chiral center contains the strongly dipolar nitrile group bound to the aliphatic spacer between aryl units in a stereo-ordered fashion. The chemical structure of the comb polymer is shown below:

scholarly journals Temperature dependant structural changes in thin films of random semifluorinated PMMA copolymers

2013 ◽  
Vol 28 (S2) ◽  
pp. S144-S160 ◽  
Author(s):  
Dieter Jehnichen ◽  
Peter Friedel ◽  
Romy Selinger ◽  
Andreas Korwitz ◽  
Martin Wengenmayr ◽  
...  
Keyword(s):  
Thin Films ◽  
Phase Separation ◽  
Structural Changes ◽  
Bulk Material ◽  
Fluorine Content ◽  
Film Surface ◽  
Phase Behaviour ◽  
Side Chain ◽  
Side Chains ◽  
Polymer Backbone

Semifluorinated (SF) side chain polymers show phase separation between polymer backbone and SF side chains. Due to strong interaction between SF segments the side chains determine the structure behaviour strongly, often resulting in layered structures in which backbones and layers of SF side chains alternate. The interest in this work was directed to find out the dependence of these structures on concentration of SF side chains. Thin films of random copolymers consisting of methylmethacrylate (MMA) and semifluorinated side chain methacrylate (SFMA) segments and with different fluorine content in the perfluoroalkyl side chains (abbreviated as H10F10 and H2F8) were prepared by spin-coating. Phase separation and structure changes were initiated by external subsequent annealing. Corresponding bulk material served as basic information. Generation of ordered structures and variation of film parameters were observed using different X-ray scattering methods (XRR, GIWAXS, and GISAXS). The phase behaviour in bulk is governed by the SF side chain amount and their specific fluorine content which control the self-organization tendency of SF side chains. Additionally, the confinement in thin films generates an orientation of side chains normally to film surface.

Side chain effect on conjugated polymer/fullerene interfaces in organic solar cells: a DFT study

2019 ◽  
Vol 21 (43) ◽  
pp. 23978-23995 ◽  
Author(s):  
Sarah A. Ayoub ◽  
Jolanta B. Lagowski
Keyword(s):  
Solar Cells ◽  
Organic Solar Cells ◽  
Conjugated Polymer ◽  
Binding Energies ◽  
Dft Study ◽  
Side Chain ◽  
Side Chains

We investigated the effect of lengths, types, and branching positions of side chains on the binding energies of monomer/fullerene pairings.

Tuning the thermal conductivity of solar cell polymers through side chain engineering

2014 ◽  
Vol 16 (17) ◽  
pp. 7764-7771 ◽  
Author(s):  
Zhi Guo ◽  
Doyun Lee ◽  
Yi Liu ◽  
Fangyuan Sun ◽  
Anna Sliwinski ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Solar Cell ◽  
Conjugated Polymer ◽  
Side Chain ◽  
Polymer Backbone

Side chain engineering of the conjugated polymer backbone improves its thermal conductivity.

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