- Synthesis of recyclable, chemically cross-linked, high toughness, high conductivity ion gels by sequential triblock copolymer self-assembly and disulfide bond cross-linking
-
In this article, we report the synthesis of a disulfide bonded reversibly chemically cross-linked ion gel with high toughness and conductivity by sequential triblock copolymer self-assembly and the subsequent oxidation of thiol groups. Through reversible thiol-disulfide exchange, the ion gels had both high toughness of chemicals and recyclability of physical cross-linked ion gels. The triblock copolymer (SOS-SH) was prepared as follows: first, the RAFT copolymerization of styrene and 4-vinylbenzyl chloride (VBC) using CTA-PEO-CTA as a bi-functional macroRAFT agent was performed to obtain a triblock copolymer (SOS-Cl); then, the chloride group of SOS-Cl was replaced by an azido group to obtain SOS-N3; and finally, the click reaction of SOS-N3 with O-ethyl-S-prop-2-ynyl carbonodithioate and subsequent aminolysis were conducted to obtain SOS-SH. The disulfide bonded reversibly chemically cross-linked ion gel could be re-dissolved when mixed with a little amount of mild reducing agent (e.g., DTT) in CH2Cl2 with vigorous stirring, which reformed again after the removal of solvent and oxidation of thiol groups. The ion gels could undergo the reduction-oxidation cycle at least twice with a little loss of ionic conductivity and toughness (less than 25%), exhibiting good recyclability. Raman measurements were performed to confirm the existence and the key role of disulfide bond on the recyclability. This journal is
- Wei, Chengsha,Chen, Mingming,Liu, Dong,Zhou, Weiming,Khan, Majid,Wu, Xibo,Huang, Ningdong,Li, Liangbin
-
-
Read Online
- Preparation of an Antibacterial Poly(ionic liquid) Graft Copolymer of Hydroxyethyl Cellulose
-
Poly(ionic liquid)s (P(IL)s) of different degrees of polymerization (10, 50, and 100) were prepared via RAFT polymerization using an alkyne-terminated xanthate as transfer agent, with a monomer conversion of up to ~80% and a DM of 1.5 for P(IL)100. Subsequently, P(IL) chains were coupled to 15N-labeled azido-functionalized hydroxyethyl cellulose (HEC), forming graft copolymers of HEC with different chain length and graft densities, which were characterized using (13C and 15N) CP-MAS NMR and FT-IR spectroscopies. The antibacterial activities of HEC-g-P(IL)s were tested against Escherichia coli and Staphylococcus aureus and were comparable to ampicillin, a well-known antibiotic, demonstrating efficient activity of the graft copolymers against bacteria. Moreover, HEC-g-P(IL)s were slightly more effective against E. coli than S. aureus. A decrease in graft density of P(IL)10 on the HEC backbone decreased the activity of the graft copolymers against both bacteria. These findings suggest that HEC-g-P(IL) could find applications as an antiseptic compound, for example, in paint formulation.
- Joubert, Fanny,Yeo, R. Paul,Sharples, Gary J.,Musa, Osama M.,Hodgson, David R. W.,Cameron, Neil R.
-
-
Read Online
- Xanthates as Thiol Surrogates for Nucleophilic Substitution with Aryl Halides
-
We herein report an unprecedented xanthate-based protocol for the preparation of aryl-alkyl thioethers. Heating xanthates with aryl halides and namely cesium carbonate in methanol provides the target thioethers in generally good yields within short reaction times. This method allows one to avoid contact with odorous thiols and also to introduce substituents of which the corresponding thiols are virtually unavailable or inconvenient in use.
- Sokolov, Anatolii I.,Mikhaylov, Andrey A.,Baleeva, Nadezhda S.,Baranov, Mikhail S.
-
p. 4350 - 4357
(2021/08/24)
-