Electrified Interactions of Polyzwitterions with Charged Surfaces: Role of Dipole Orientation and Surface Potentials.

The zwitterionic groups possess strong dipole moments, leading to inter- or intrachain interactions among zwitterionic polymers. This study aims to demonstrate the interaction of polyzwitterions poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC), and poly(carboxybetaine methacrylate) (PCBMA) with electrified surfaces, despite their electrically neutral nature. We studied the adsorption of polyzwitterions and their monomers on electrified surfaces by using an electrochemical quartz crystal microbalance with dissipation (EQCM-D). The interaction between zwitterionic molecules and charged surfaces is explored by adjusting the surface potentials. Interestingly, the adsorption of polyzwitterions can be influenced by external potential, primarily due to the formation of polyzwitterions restricting the mobility of zwitterionic groups, affecting the adsorption behavior of polyzwitterions based on the surface potential. The impact is determined by the arrangement of positive and negative ions within the zwitterionic groups, which are the dipole orientation. Additionally, surface potentials determine the adsorption rate, amount, and chain conformation of the adsorbed thin polyzwitterion layers. The effect of ionic strength was investigated by introducing electrolytes into the aqueous solutions to assess the range of influenced surface potentials.

Engineering Superaerophobic Electrodes Using Hydrophilic PEDOT and Colloidal Lithography for Enhanced Bubble Release and Efficient Hydrogen Evolution Reaction.

The efficient removal of gas bubbles is essential to reduce the reaction overpotential and improve the electrode stability in the hydrogen evolution reaction (HER). To address this challenge, the current study combines hydrophilic functionalized poly(3,4-ethylenedioxythiophene) (PEDOT) with colloidal lithography to create superaerophobic electrode surfaces. The fabrication process involves the use of polystyrene (PS) beads with varying sizes (100, 200, and 500 nm) as hard templates and the electropolymerization of EDOTs with hydroxymethyl (EDOT-OH) and sulfonate (EDOT-SuNa) functional groups. The surface properties and HER performances of the electrodes are investigated. The electrode modified with poly(EDOT-SuNa) and 200 nm PS beads (SuNa/Ni/Au-200) exhibits the best hydrophilicity with a water contact angle of 37°. Moreover, the overpotential required at -10 mA cm-2 is substantially reduced from -388 mV (flat Ni/Au) to -273 mV (SuNa/Ni/Au-200). This approach is further applied to commercially available nickel foam electrodes, showing improved HER activity and electrode stability. These results highlight the potential for promoting catalytic efficiency by constructing a superaerophobic electrode surface.

Electropolymerized Poly(3,4-ethylenedioxythiophene)/Screen-Printed Reduced Graphene Oxide-Chitosan Bilayer Electrodes for Flexible Supercapacitors.

An electropolymerized poly(3,4-ethylenedioxythiophene) (PEDOT)/screen-printed reduced graphene oxide (rGO)-chitosan (CS) bilayer material was coated on carbon cloth to form electrodes for gel-electrolyte flexible supercapacitors. The conductive polymer and carbon-based materials mainly contribute pseudocapacitance (PC) and electrical double-layer capacitance (EDLC), respectively. The high porosity and hydrophilicity of the PEDOT/rGO-CS bilayer material offers a large contact area and improves the contact quality for the gel electrolyte, thereby enhancing the capacitive performance. Cyclic voltammetry (CV) under a potential scan rate of 2 mV/s revealed that a maximum areal capacitance of 1073.67 mF/cm2 was achieved. The capacitance contribution ratio PC/EDLC was evaluated to be ∼67/33 by the Trasatti method. A 10,000-cycle CV test showed a capacitance retention rate of 99.3% under a potential scan rate of 200 mV/s, indicating good stability. The areal capacitance remains similar under bending with a bending curvature of up to 1.5 cm-1.