Local dynamics of freely rotating polymer chains in dense systems

2007 ◽  
pp. 16-19
Author(s):  
B. Erman ◽  
I. Bahar
Keyword(s):  
Polymer Chains ◽  
Local Dynamics

Local dynamics of cross-linked polymer chains

1992 ◽  
Vol 2 (8) ◽  
pp. 1495-1503 ◽  
Author(s):  
A. Lapp ◽  
T. Csiba ◽  
B. Farago ◽  
M. Daoud
Keyword(s):  
Polymer Chains ◽  
Local Dynamics

Polymer chains grow one ‘hairball’ at a time

Nature ◽  
2017 ◽  
Vol 550 (7677) ◽  
pp. 432-432
Keyword(s):  
Polymer Chains

Shape of Confined Polymer Chains

1997 ◽  
Vol 7 (3) ◽  
pp. 433-447 ◽  
Author(s):  
C. E. Cordeiro ◽  
M. Molisana ◽  
D. Thirumalai
Keyword(s):  
Polymer Chains ◽  
Confined Polymer ◽  
Confined Polymer Chains

Dynamics of polymer chains trapped in a slit

1977 ◽  
Vol 38 (10) ◽  
pp. 1285-1291 ◽  
Author(s):  
F. Brochard
Keyword(s):  
Polymer Chains

A Donor Influenced by Local Dynamics

2016 ◽  
Vol 2 (1) ◽  
pp. 51-69 ◽  
Author(s):  
Setsuko Matsuzawa
Keyword(s):  
Poverty Alleviation ◽  
Rural Poverty ◽  
Unintended Consequences ◽  
Local Dynamics ◽  
Grant Program ◽  
Local Actors ◽  
Research Interviews ◽  
National Model ◽  
Management Project ◽  
Development Discourses

This article explores the relations between a foreign aid donor and local actors in the context of the dissemination of development discourses and practices in an authoritarian context. It addresses the question “To what extent may the local dynamics alter the original goals of a donor and lead to unintended consequences?” Based on archival research, interviews, and secondary literature, this case study examines the Yunnan Uplands Management Project (YUM) in 1990–95, the Ford Foundation's first grant program on rural poverty alleviation in China. While the Foundation did not attain its main goal of making YUM a national model for poverty alleviation, the local actors were able to use YUM to develop individual capacities and to build roles for themselves as development actors in the form of associations and nongovernmental organizations, resulting in further support from the Foundation. The study contributes to our understanding of donor-local actor dynamics by highlighting the gaps between the original goals of a donor and the perspectives and motivations of local actors. The study suggests that local dynamics may influence the goals of donors and the ways they seek to disseminate development discourses and practices to local actors, despite the common conception of donors as hegemonic or culturally imperialistic.

SuFExable Polymers with Helical Structures Derived from Thionyl Tetrafluoride (SOF4)

2019 ◽  
Author(s):  
Suhua Li ◽  
Gencheng Li ◽  
Bing Gao ◽  
Sidharam P. Pujari ◽  
Xiaoyan Chen ◽  
...  
Keyword(s):  
Functional Polymers ◽  
Polymer Chains ◽  
New Materials ◽  
Helical Structures ◽  
Polymer Backbone ◽  
Silyl Ethers ◽  
Helical Polymer ◽  
Key Characteristics ◽  
Post Modification ◽  
Individual Polymer

The first SuFEx click chemistry synthesis of SOF<sub>4</sub>-derived copolymers based upon the polymerization of bis(iminosulfur oxydifluorides) and bis(aryl silyl ethers) is described. This novel class of SuFEx polymer presents two key characteristics: First, the newly created [-N=S(=O)F-O-] polymer backbone linkages are themselves SuFExable and primed to undergo further high-yielding and precise SuFEx-based post-modification with phenols or amines to yield branched functional polymers. Second, studies of individual polymer chains of several of these new materials indicate the presence of helical polymer structures, which itself suggests a preferential approach of new monomers onto the growing polymer chain upon the formation of the stereogenic linking moiety.

Microstructure determines water and salt permeation in commercial ion exchange membranes

2018 ◽  
Author(s):  
Ryan Kingsbury ◽  
Shan Zhu ◽  
Sophie Flotron ◽  
Orlando Coronell
Keyword(s):  
Energy Efficiency ◽  
Ion Exchange ◽  
Electrolyte Solutions ◽  
Polymer Chains ◽  
Salt Transport ◽  
Mixing Energy ◽  
Electrochemical Processes ◽  
Highly Correlated ◽  
Salt Diffusion ◽  
Exchange Membrane

Ion exchange membrane (IEM) performance in electrochemical processes such as fuel cells, redox flow batteries, or reverse electrodialysis (RED) is typically quantified through membrane selectivity and conductivity, which together determine the energy efficiency. However, water and co-ion transport (i.e., osmosis and salt diffusion / fuel crossover) also impact energy efficiency by allowing uncontrolled mixing of the electrolyte solutions to occur. For example, in RED with hypersaline water sources, uncontrolled mixing consumes 20-50% of the available mixing energy. Thus, in addition to high selectivity and high conductivity, it is desirable for IEMs to have low permeability to water and salt in order to minimize energy losses. Unfortunately, there is very little quantitative water and salt permeability information available for commercial IEMs, making it difficult to select the best membrane for a particular application. Accordingly, we measured the water and salt transport properties of 20 commercial IEMs and analyzed the relationships between permeability, diffusion and partitioning according to the solution-diffusion model. We found that water and salt permeance vary over several orders of magnitude among commercial IEMs, making some membranes better-suited than others to electrochemical processes that involve high salt concentrations and/or concentration gradients. Water and salt diffusion coefficients were found to be the principal factors contributing to the differences in permeance among commercial IEMs. We also observed that water and salt permeability were highly correlated to one another for all IEMs studied, regardless of polymer type or reinforcement. This finding suggests that transport of mobile salt in IEMs is governed by the microstructure of the membrane, and provides clear evidence that mobile salt does not interact strongly with polymer chains in highly-swollen IEMs. <br>

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