Conjugated and fluorescent polymer based on dansyl-substituted carbazole: Investigation of electrochromic and ion sensitivity performance

Fluorescent conjugated polymers have been used as excellent optical sensing materials to develop high sensitive and selective sensors by using their large extinction coefficient and high fluorescence quantum yield. Thanks to these features, conjugated polymers are used in a wide range of applications, including metal ion sensing and detection. In this study, a dansyl-substituted fluorescent polycarbazole was synthesized by electrochemical polymerization of 9H-carbazol-2-yl 5-(dimethylamino)naphthalene-1-sulfonate (CZD). CZD was characterized by 1H-NMR, FT-IR, UV-vis and fluorescence spectroscopy. Optical and electrochemical properties of polymer (PCZD) were investigated by voltammetric, spectroelectrochemical, kinetic studies and colorimetry measurements. Polymer showed a reversible electrochromic behavior from green to light yellow color. Moreover, the sensitivities of CZD toward metal cations were examined by observing the change in the fluorescence intensity. CZD was found to be selective toward Zn2+ with significant quenching emission intensity while the other metal ions did not show any interaction with CZD. This novel monomer CZD can be used as metal ion sensor, besides PCZD used in good electronic and optical applications. © 2017 The Electrochemical Society. All rights reserved

Degradation of Poly(2-hydroxyethyl methacrylate) Obtained by Radiation in Aqueous Solution

The degradation of poly(hydroxyethyl methacrylate), PHEMA obtained by -radiation induced polymerization of HEMA in aqueous solution, was studied. The polymer was a gel type and insoluble in common organic solvents. The DSC thermogram of the polymer gave a Tg value at 88.2 degrees C and an endothermic peak showed further polymerization or crosslinking at 110-160 degrees C. The degradation observed in TGA was a depolymerization type. However, the FT-IR of TGA fragments showed no monomer, which was degraded further. The degradation of monomer was studied by the GC-MS method. Similar results were also observed

Biodegradable porous polylactic acid film as a separator for supercapacitors

A porous polylactic acid (PLA) film was investigated as a separator for supercapacitors (SCs) and compared with commercial separators, for example, NKK-MPF30AC and Celgard 2400. The porous PLA film was fabricated via a facile phase inversion method, and the cross-sectional scanning electron microscope images of the PLA separator film exhibited highly porous interconnected morphology for ion diffusion. The surface modification of separators was performed by radio frequency (RF) air plasma to improve wettability. The plasma modification enhanced the water uptake and swelling properties of the separators and decreased the water contact angles of PLA and Celgard 2400 films. The mechanical and dielectric properties of separators were also studied. The ionic conductivities of RF-PLA in 1 M H2SO4 and 1 M Na2SO4 were found to be 1.1 × 10−1 S/cm and 0.6 × 10−2 S/cm at room temperature, respectively. The electrochemical impedance spectroscopy of the RF-PLA SCs showed the lowest solution resistance and internal resistance. © 2020 Wiley Periodicals, Inc.National Key R&D Program of China [2016YFE0131200]; European Regional Development FundEuropean Union (EU); Ministry of Education, Youth, and Sports of the Czech RepublicMinistry of Education, Youth & Sports - Czech Republic [LTACH17015

Cell response to PLA scaffolds functionalized with various seaweed polysaccharides

The porous polylactic acid matrix has been particularly developed as a scaffold in tissue engineering, drug loading, and wound dressing. However, the loading of active chemical compounds is challenging due to its highly hydrophobic nature and lack of functional groups for chemical bonding. Plasma treatment is a fast, heat and chemical-free solution to increase its hydrophilicity by oxidative functional groups and physical etching. In this study, a highly porous PLA scaffold was obtained by polyethylene glycol pore formation agent and treated by radiofrequency (RF) air plasma. Fucoidan from Fucus vesiculosus, Macrocystis pyrifera, and Undaria pinnatifida were used to immobilize onto the activated porous PLA surface for use as medicated wound dressings. The chemical composition and morphology were investigated by FTIR, SEM-EDS analysis, and cytocompatibility assay was studied mouse embryonic fibroblast cells (NIH/3T3). © 2020 Taylor & Francis Group, LLC.Ministry of Education, Youth and Sports of the Czech RepublicMinistry of Education, Youth & Sports - Czech Republic [LO1504]; Czech Science FoundationGrant Agency of the Czech Republic [19-16861S

Reduced graphene oxide-MWCNT organogel foam for lithium-sulfur battery cathode

The fabrication of self-standing porous carbon foam nanostructures for trapping sulfur in Lithium-Sulfur (Li-S) batteries was aimed in this work. Nitrogen doped reduced graphene oxide/acid treated MWCNT based cathode material was prepared and characterized by different techniques. The GO/aMWCNT organofoam nanostructures were first polymerized in-situ with aniline and pyrrole and then carbonized at 800°C under argon atmosphere. The purpose of the carbonization was to improve the conductivity of the carbon matrix and dope it with nitrogen using PANI and PPy as a nitrogen source. N-doped rGO/aMWCNT foams exhibited the three dimensional porous network morphology and high conductivity (3.06 S.cm-1). The sulfur was infiltrated to the foams by melt diffusion method and the highest sulfur content of the rGO/aMWCNT-S composite was found as 61.3 wt. %. © The Electrochemical Society

Effect of PANI and PPy on electrochemical performance of rGO/ZnMn2O4 aerogels as electrodes for supercapacitors

Conductive polymers, such as polyaniline (PANI) and polypyrrole (PPy), are widely used in the design of supercapacitors because of their high pseudo-capacitive performance as well as facile synthesis and low cost. In this study, hybrid aerogels based on reduced graphene oxide and ZnMn2O4 were modified by PANI and PPy. The 3D structure of the hybrid aerogels was obtained by using a one-step hydrothermal co-assembly method. Then, aniline and pyrrole were polymerized on and within the structure of the hybrid aerogel through in situ polymerization. The electrochemical properties of the hybrid aerogels were studied via cyclic voltammetry and galvanostatic charge–discharge testing to identify the effects of conductive polymers on the electrochemical properties of materials. It has been established that PANI and PPy facilitate an increase of the specific capacitance of rGO/ZnMn2O4 aerogels up to 297.8 F/g and 108.24 F/g at 0.2 A/g scan rate, respectively. © 2020, The Minerals, Metals & Materials Society.Foundation for Science and Technology Development of Ton Duc Thang University (FOSTECT) [FOSTECT.2019.21]; Ministry of Education, Youth, and Sports of the Czech RepublicMinistry of Education, Youth & Sports - Czech Republic [LTACH17015]; Operational Program Research and Development for Innovations; national budget of the Czech Republic [CZ.1.05/2.1.00/19.0409]; NPU Program I [LO1504]; European Regional Development Fund (ERDF)European Union (EU