Tag Archive for: AWS A20

Scientific publication

Structure and transition behavior of crosslinked poly(2-(2-methoxyethoxy) ethylmethacrylate-co-(ethyleneglycol) methacrylate) gel film on cellulosic-based flat substrate

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Authors: Yangyi Chen, Tong Su, Shihang Zhou, Chendi Xie, Huan Qi , Zaisheng Cai and Liqun Chen

Journal: e-Polymers

Abstract

The structure and transition behavior of crosslinked thermo-responsive poly(2-(2-methoxyethoxy) ethylmethacrylate-co-(ethyleneglycol) methacrylate) (P(MEO2MA-co-EGMA360)) gel film on a flat cellulosic-based substrate were investigated. The regenerated cellulose (RC) film was prepared by spin-coating with trimethylsilyl cellulose (TMSC), followed by etching with hydrochloric acid vapor on a treated silicon wafer, then crosslinked polymer gel film was obtained by spin-coating, drying, and baking with a pre-crosslinked solution containing polymers. Fourier transform infrared spectroscopy, X-ray photoelectron spectrometer, and atomic force microscopy results show that a RC film with a thickness of 25 nm is generated in the upper layer of TMSC film on the silicon wafer. The cross-linking induces closer arrangement and hinders the extension of chain segments, leading to less prominent phase transition behaviors of polymer gel films. By quartz crystal microbalance measurement and 3D microscopes, a phase transition hysteresis is discovered, the hydrated and loose structure of crosslinked polymer gel film switches to dehydrated and compact structure in initial heating process, which subsequently recovers during the following cooling process. However, the degrees of rehydration and flexibility of film could not reach the initial value because of the insufficient transition time and steric hindrance caused by crosslinking.

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Scientific publication

Electropolymerization of thiazole derivatives bearing thiophene and selenophene and the potential application in capacitors

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Authors: Seongjun Hong, Joon Ho Yoon, Seunghyun Jeong, Yang-Rae Kim and In Tae Kim.
Journal: Journal of Electroanalytical Chemistry (2022)

 

Abstract

Three thiazole derivatives bearing thiophene and selenophene are synthesized and used as monomers for electropolymerization. The electropolymerization process is studied using cyclic voltammetry (CV) and electrochemical quartz crystal microbalance (EQCM) techniques. Deep understanding is obtained regarding the pseudocapacitor performance of deposited polymer layers by subjecting the macroelectrode and ultramicroelectrode to CV and galvanostatic charging–discharging experiments in three kinds of electrolytes. Notably, the highest specific capacitance is observed in the derivative bearing selenopheno[3,4-d]thiazole and selenophene in a solution of tetrabutylammonium tetrafluoroborate. Furthermore, the electropolymerization rate is influenced by the kind of chalcogenophene and the CV scan rate. A spectroelectrochemistry experiment reveals the optical and electrochromic behavior of the deposited polymer layers. From these results, the pseudocapacitor performance of the deposited polymer layers is related to anion intercalation/deintercalation processes by faradaic reactions of oligomer chains. The EQCM experiments also reveal these processes during electropolymerization and anion intercalation/deintercalation into the deposited polymer layers. Finally, the approximate molecular weight of the solvated anion and the number of solvent molecules surrounding a solvated anion are analyzed using the EQCM data.

 

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