Tunable Donnan Potential and Electrokinetic Flow in a Biomimetic Gated Nanochannel with pH-Regulated Polyelectrolyte Brushes

2014 ◽  
Vol 118 (34) ◽  
pp. 19806-19813 ◽  
Author(s):  
Zachary Milne ◽  
Li-Hsien Yeh ◽  
Tzung-Han Chou ◽  
Shizhi Qian
Keyword(s):  
Donnan Potential ◽  
Electrokinetic Flow ◽  
Polyelectrolyte Brushes

Field effect regulation of Donnan potential and electrokinetic flow in a functionalized soft nanochannel

Soft Matter ◽  
2013 ◽  
Vol 9 (41) ◽  
pp. 9767 ◽  
Author(s):  
Laura Benson ◽  
Li-Hsien Yeh ◽  
Tzung-Han Chou ◽  
Shizhi Qian
Keyword(s):  
Field Effect ◽  
Donnan Potential ◽  
Electrokinetic Flow ◽  
Soft Nanochannel

JOULE HEATING INDUCED HEAT TRANSFER IN ELECTROKINETIC FLOW THROUGH MICROFLUIDIC CHANNELS

Equipment ◽  
2006 ◽  
Author(s):  
C. Yang ◽  
G. Y. Tang ◽  
D. G. Yan ◽  
H. Q. Gong ◽  
John C. Chai ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Joule Heating ◽  
Microfluidic Channels ◽  
Electrokinetic Flow ◽  
Flow Through

Ion Pairing and Dielectric Decrement in Glycosaminoglycan Brushes

2020 ◽  
Author(s):  
James Sterling ◽  
Wenjuan Jiang ◽  
Wesley M. Botello-Smith ◽  
Yun L. Luo
Keyword(s):  
Molecular Dynamics ◽  
Ion Pairs ◽  
Mean Field ◽  
Salt Bridge ◽  
Ion Pairing ◽  
Donnan Potential ◽  
Mean Field Models ◽  
Ion Exclusion ◽  
Dynamics Simulations ◽  
Contact Ion Pairs

Molecular dynamics simulations of hyaluronic acid and heparin brushes are presented that show important effects of ion-pairing, water dielectric decrease, and co-ion exclusion. Results show equilibria with electroneutrality attained through screening and pairing of brush anionic charges by cations. Most surprising is the reversal of the Donnan potential that would be expected based on electrostatic Boltzmann partitioning alone. Water dielectric decrement within the brush domain is also associated with Born hydration-driven cation exclusion from the brush. We observe that the primary partition energy attracting cations to attain brush electroneutrality is the ion-pairing or salt-bridge energy associated with cation-sulfate and cation-carboxylate solvent-separated and contact ion pairs. Potassium and sodium pairing to glycosaminoglycan carboxylates and sulfates consistently show similar abundance of contact-pairing and solvent-separated pairing. In these crowded macromolecular brushes, ion-pairing, Born-hydration, and electrostatic potential energies all contribute to attain electroneutrality and should therefore contribute in mean-field models to accurately represent brush electrostatics.

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.

Low-Concentration Salt Solution Changes the Interfacial Molecular Behavior of Polyelectrolyte Brushes

2021 ◽  
Author(s):  
Yongsheng Luo ◽  
Chu Wang ◽  
Ai-Ping Pang ◽  
Xiang Zhang ◽  
Dayang Wang ◽  
...  
Keyword(s):  
Salt Solution ◽  
Low Concentration ◽  
Polyelectrolyte Brushes ◽  
Molecular Behavior ◽  
Solution Changes

scholarly journals Determination of the molar mass of surface-grafted weak polyelectrolyte brushes using force spectroscopy

Polymer ◽  
2015 ◽  
Vol 67 ◽  
pp. 111-117 ◽  
Author(s):  
Ateyyah AL-Baradi ◽  
Michael R. Tomlinson ◽  
Zhenyu J. Zhang ◽  
Mark Geoghegan
Keyword(s):  
Molar Mass ◽  
Force Spectroscopy ◽  
Polyelectrolyte Brushes
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