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.

An easy and ecofriendly method for designing double‐network (DN) hydrogels based on chitosan and poly(vinyl alcohol) (PVA) with high mechanical performance is described. When covalent bonds in the networks are used as crosslinking agents in the achievement of a higher mechanical strength, the irreversible deformation of these hydrogels after a large force is applied is still one of the most important obstacles. To overcome this problem, we used physical crosslinking for both networks. The mechanical strength, surface morphology, and cytotoxicity of the films were studied by tensile testing, scanning electron microscopy analysis, and an MTT assay. The synthesized chitosan–PVA DN hydrogels showed a large improvement in the tensile strength to 11.52 MPa with an elongation of 265.6%. The surface morphologies of the films demonstrated the effective interactions between the two networks and a suitable porosity. Also, because of the use of a natural polymer and honey as a plasticizer, the cell culture indicated that the synthesized DN hydrogels had good biocompatibility (with 327.49 ± 11.22% viability) and could be used as capable biomaterials. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45752.

Membranes with asymmetric wettability-Janus membranes-have recently received considerable attention for a variety of critical applications. Here, we report on a simple approach to introduce asymmetric wettability into hydrophilic porous domains. Our approach is based on the physicochemical-selective deposition of polytetrafluoroethylene (PTFE) on hydrophilic polymeric substrates. To achieve selective deposition of PTFE, we inhibit the polymerization reaction within the porous domain. We prefill the substrates with glycerol, containing a known amount of free radical inhibitor, and utilize initiated chemical vapor deposition (iCVD) for the polymerization of PTFE. We show that the glycerol/inhibitor mixture hinders the deposition of PTFE within the membrane pores. As a result, the surface of the substrates remains open and porous. The fabricated Janus membranes show stable wetting-resistant properties, evaluated through sessile drop contact angle measurements and direct contact membrane distillation (DCMD).