Displaying 1 - 3 of 3
Homopolymer PAN and triblock copolymer PAN-<b>b</b>-PMMA-<b>b</b>-PAN synthesized by RAFT polymerization were used to fabricate activated hierarchical porous carbon membranes by combining phase inversion, carbonization, and HNO3 activation method; during the preparation process, a lot of micro- and meso-pores generated because of phase separation of PAN and microphase separation of PAN-<b>b</b>-PMMA-<b>b</b>-PAN. The hierarchical porous structure shortened ions transport paths and facilitated the rapid migration of electrolyte ions. When the polymer membrane was prepared by the casting solution with 5 wt% of PAN-<b>b</b>-PMMA-<b>b</b>-PAN and the electrochemical performance was tested at the current densities from 0.5 to 5 A g−1, a high-end specific capacitance of 297.0 F g−1 and a capacitance retention of 75% were obtained in three-electrode configuration; this specific capacitance remained above 90% of initial value after 2000 cycles at 2 A g−1 in 6 M KOH aqueous solution. Moreover, symmetric supercapacitors assembled with the prepared materials achieved high energy density (15.8 Wh Kg−1) and power density (4000 W Kg−1) in 1 M Na2SO4 solution. The unique features and structures endowed the electrode membrane with good capacitive performance in both three-electrode and two-electrode configuration, which can be used as electrode membranes for high-performance energy storage devices and other applications.<br><br>Display Omitted<br>• An electrode membrane of activated hierarchical porous carbon was fabricated • Micro- and meso-pores generated due to the phase and microphase separation. • Effects of copolymer concentration on structure and performance were studied • High electrochemical performance for supercapacitor was obtained.
In this study, an environmentally friendly approach for surface modification of polymer membrane was reported, which named surface-initiated electrochemically mediated atom transfer radical polymerization (SI-eATRP). It was triggered after diffusion of a CuI/L activator generated at a working electrode. The introduction of electrochemically mediation can control the polymerization of monomers by a one-electron reduction of an initially added air-stable CuII salt. The reaction was carried out in an electrochemical cell with a three-electrode system at low temperature. Using this technique, hydrophilic polymer brushes of poly(N-vinylpyrrolidone) were grafted onto PES membrane surface. The effects of reaction conditions like polymerization time, monomer concentration, initiator amount, and different monomer on the polymerizations of monomer were investigated in detail. Based on these data, we concluded that the polymerization on polymer membrane surface could be controlled by mediating the reaction condition. Moreover, the precisely controlled polymerization may allow it to serve as excellent model systems for polymer membrane modification, in general, to illustrate the role of electrochemically mediating on the polymerization approach. And the water contact angle of the modified membrane decreased from 89° to 72°. The APTT of the modified membrane increased from 46 s to 81 s. Those results indicated that the surface modification by grafting PVP brushes provided practical application for the PES membranes with high surface properties.