Polymer from 3,4-ethylenedioxythiophene (EDOT) was synthesized using oxidative chemical vapor deposition (oCVD). To enable the synthesis of PEDOT, two different oxidants, antimony pentachloride (SbCl 5 ) and vanadium oxytrichloride (VOCl 3 ), were utilized. The effect of deposition temperature on the polymer electroactivity and conductivity was evaluated by measuring the overpotential for the oxygen reduction reaction and film electrical conductivity, respectively. PEDOT films with conductivity values of ∼2000 S/ cm were deposited in a single step coating and doping process. X-ray photoelectron spectroscopy revealed that the residual metalloid within polymer films, in the case of SbCl 5 , is contributing to the hole conductivity. The electrocatalytic activity of deposited material in oxygen reduction reaction (ORR) was studied; the results indicate a direct relationship between the conductivity values and the electrocatalytic activities of the deposited films. The unique potential offered by oCVD to coat PEDOT conformally enabled us to apply a coat of electroactive polymers on complex structures of a gas diffusion layer fabric, carbon cloth. Using our approach, we imparted stable electrocatalytic activity to carbon cloth electrodes and fabricated all-organic electrodes for ORR.

Synthesis and processing of two- or three-dimensional covalent organic frameworks (COFs) have been limited by solvent intractability and sluggish condensation kinetics. Here, we report on the electrochemical deposition of poly­(5,10,15,20-tetrakis­(4-aminophenyl)­porphyrin)-covalent organic frameworks (POR-COFs) via formation of phenazine linkages. By adjusting the synthetic parameters, we demonstrate the rapid and bottom-up synthesis of COF dendrites. Both experiment and density functional theory underline the prominent role of pyridine, not only as a polymerization promoter but as a stabilizing sublattice, cocrystallizing with the framework. The crucial role of pyridine in dictating the structural properties of such a cocrystal (Py-POR-COF) is discussed. Also, a structure-to-function relationship for this class of materials, governing their electrocatalytic activity for the oxygen reduction reaction in alkaline media, is reported.

Desalination of oil-contaminated saline water using membrane distillation requires hydrophobic membranes with underwater superoleophobic surfaces. For designing such membranes, the chemistry and morphology of the interfacial domains in contact with the contaminated water need to be adjusted such that a stable water layer, adhering to the surface, prevents oil droplets from wetting the membrane. In this article, we present an approach that relies on the controlled functionalization of the surface of polyvinylidene fluoride (PVDF) membranes; we adjust the surface topography of the membranes and introduce chemical heterogeneity to them. We show that the morphology of the PVDF surface can be altered by adjusting the composition of the nonsolvent bath used for the phase inversion process. Also, we render the surface of the membranes hydrophilic by using an alkaline chemical bath solution. The membrane morphology and effectiveness of our chemical treatment were confirmed by atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), Fourier-transformed infrared spectroscopy (FTIR), and zeta potential measurements. A stable underwater contact angle, higher than 150°, was observed for both canola oil (ρ ≈ 0.913 g cm −3 , γ ≈ 31.5 mN m −1 ) and hexane (ρ ≈ 0.655 g cm −3 , γ ≈ 18 mN m −1 ). We evaluated the performance of both pristine and functionalized membranes in a laboratory-scale direct contact membrane distillation (DCMD) setup and desalinated a saline solution contaminated with 500 ppm canola oil. Our results show that oil does not wet the functionalized membrane during the desalination process. The average permeate flux and salt rejection values for the functionalized membranes were 45 ± 5 Lm -2 h -1 (T feed = 70 °C, T distillate = 20 °C) and 99.99%, respectively.

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Creating reentrant structures on flexible and porous substrates is a significant challenge for the scalable fabrication of omniphobic membranes. The design of such membranes requires control over the surface topography and chemistry of the interfacial domains. Here, a continuous bottom-up method, based on initiated chemical vapor deposition (iCVD), is developed to enable the fabrication of flexible omniphobic membranes. The developed membranes hinder the intrusion of droplets of low surface energy liquids (e.g., ethanol) colliding with the surface at a velocity of about 2 m/s. The stable wetting resistance of the membranes allows for the desalination of low surface energy synthetic and municipal wastewater streams.