scholarly journals Supramolecular polymer assembly in aqueous solution arising from cyclodextrin host–guest complexation

2016 ◽  
Vol 12 ◽  
pp. 50-72 ◽  
Author(s):  
Jie Wang ◽  
Zhiqiang Qiu ◽  
Yiming Wang ◽  
Li Li ◽  
Xuhong Guo ◽  
...  

The employment of cyclodextrin host–guest complexation to construct supramolecular assemblies with an emphasis on polymer networks is reviewed. The main driving force for this supramolecular assembly is host–guest complexation between cyclodextrin hosts and guest groups either of which may be discrete molecular species or substituents on a polymer backbone. The effects of such complexation on properties at the molecular and macroscopic levels are discussed. It is shown that cyclodextrin complexation may be used to design functional polymer materials with tailorable properties, especially for photo-, pH-, thermo- and redox-responsiveness and self-healing.

2017 ◽  
Vol 29 (22) ◽  
pp. 1605325 ◽  
Author(s):  
Ji Liu ◽  
Cindy Soo Yun Tan ◽  
Ziyi Yu ◽  
Nan Li ◽  
Chris Abell ◽  
...  

RSC Advances ◽  
2015 ◽  
Vol 5 (122) ◽  
pp. 101148-101154 ◽  
Author(s):  
Chih-Chia Cheng ◽  
Feng-Chih Chang ◽  
Jem-Kun Chen ◽  
Tzu-Yin Wang ◽  
Duu-Jong Lee

A new urea–cytosine-functionalized supramolecular polymer can be rapidly reshaped and reprocessed under mild conditions via rearrangement of the hydrogen bonding network.


2011 ◽  
Vol 44 (13) ◽  
pp. 5465-5472 ◽  
Author(s):  
Donghua Xu ◽  
Stephen L. Craig

Author(s):  
Prasant Vijayaraghavan ◽  
Vishnu-Baba Sundaresan

Ionomers are a class of polymers which contain a small fraction of charged groups in the polymer backbone. These ionic groups aggregate (termed ionic aggregates) to form temporary cross-links that break apart over the ionic dissociation temperature and re-aggregate on cooling, influencing the mechanical properties of these polymers. In addition to enhanced mechanical properties, some ionomers also exhibit self-healing behavior. The self-healing behavior is a consequence of weakly bonded ionic aggregates breaking apart and re-aggregating after puncture or a ballistic impact. The structure and properties of ionomers have been studied over the last several decades; however, there is a lack of understanding of the influence of an electrostatic field on ionic aggregate morphology. Characterizing the effect of temperature and electric field on the formation and structure of these ionic aggregates will lead to preparation of ionomers with enhanced structural properties. This work focuses on Surlyn 8940 which a poly-ethylene methacryclic acid co-polymer in which a fraction of the carboxylic acid is terminated by sodium. In this work, Surlyn is thermoelectrically processed over its ionic dissociation temperature in the presence of a strong electrostatic field. Thermal studies are performed on the ionomer to study the effect of the thermoelectric processing. It is shown that the application of a thermoelectric field leads to increase in the ionic aggregate order in these materials and reduction in crystal size distribution. Thermal Analysis is performed using a Differential Scanning Calorimeter and the resulting thermogram analysis shows that thermoelectric processing increases the peak temperature and onset temperature of melting by 4 C and 20 C respectively. The peak width at half maximum of the melting endotherm is reduced by 10 C due to thermoelectric processing. This serves as a measure of the increased crystallinity. A parametric study on the effect of field duration and field strength is also performed.


2013 ◽  
Vol 873 ◽  
pp. 206-210
Author(s):  
Kai Li ◽  
Rao Fu ◽  
Qing Ran Gao ◽  
Ai Wei Tang ◽  
Ying Feng Wang

This paper continues our previous work on preparation of triangular silver nanoparticles. The method proceeds with reaction of silver nitrate with hydrazine hydrate in the presence of polyvinyl pyrrolidone in aqueous solution. Effects of the concentration of PVP on the morphologies of Ag NPs were systematically investigated. The obtained Ag NPs were characterized by transmission electron microscopy and UV-visible spectrophotometer. The results showed that, triangular Ag NPs with edge lengths in the range of 50-200 nm were obtained using PVP as protective agent with lower concentration. As the concentration of PVP increased, spherical Ag NPs with their sizes about 6.2 nm were prepared and triangular Ag NPs were not obtained. The formation mechanism of triangular Ag NPs has been studied. Ostwald ripening is the driving force on the conversion of spherical Ag NPs to triangular Ag NPs in the presence of PVP.


2021 ◽  
Vol 7 (1) ◽  
pp. 9
Author(s):  
Cansu Esen ◽  
Baris Kumru

As a metal-free polymeric semiconductor with an absorption in the visible range, carbon nitride has numerous advantages for photo-based applications spanning hydrogen evolution, CO2 reduction, ion transport, organic synthesis and organic dye degradation. The combination of g-C3N4 and polymer networks grants mutual benefit for both platforms, as networks are upgraded with photoactivity or formed by photoinitiation, and g-C3N4 is integrated into novel applications. In the present contribution, some of the recently published projects regarding g-C3N4 and polymeric materials will be highlighted. In the first study, organodispersible g-C3N4 were incorporated into a highly commercialized porous resin called poly(styrene-co-divinylbenzene) through suspension photopolymerization, and performances of resulting beads were investigated as recyclable photocatalysts. In the other study, g-C3N4 nanosheets were embedded in porous hydrogel networks, and so-formed hydrogels with photoactivity were transformed either into a ‘hydrophobic hydrogel’ or pore-patched materials via secondary network introduction, where both processes were accomplished via visible light. Since g-C3N4 is an organic semiconductor exhibiting sufficient charge separation under visible light illumination, a novel method for the oxidative photopolymerization of EDOT was successfully accomplished. As a result of the absence of dissolved anions during polymerization, so-formed neutral PEDOT is a highly viscous liquid that can be processed and post-doped easily, and grants facile coating processes.


Author(s):  
Shanjun Ding ◽  
Zhu Wang ◽  
Guocui Zhu ◽  
Ximing Zhang ◽  
Jun Zhang ◽  
...  

2021 ◽  
Author(s):  
Prantik Mondal ◽  
Gourhari Jana ◽  
Tuhin Subhra Pal ◽  
Pratim K. Chattaraj ◽  
Nikhil K Singha

Nowadays, the design of functional polymer materials that can mimic natural phenomena, e.g., self-healing of skin cuts, has got a tremendous interest in materials science and engineering. Recently, 1,2,4-triazoline-3,5-dione (TAD)...


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