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Electrokinetic properties such as the mobility, surface charge, and zeta potential of sub-millimeter particles are vital parameters in various industrial applications. Their measurement and control in aqueous media have been extensively studied. However, despite their growing importance, the electrokinetic properties of organic solvents have not been studied as thoroughly as those of aqueous media. An electrophoresis cell with a microscope monitor was designed for the electrokinetic studies of sub-millimeter particles in cyclohexane, which is a solvent with very low permittivity. The movement of large particles in the range of 4 ~ 478 µm was successfully traced under a strong electric voltage up to 1100 V, even without the addition of surfactants. The particle sizes were at least 300 times larger than those reported previously. By applying electric fields up to 55 kV/m, the electrophoretic mobilities were measured to be of the order of 10-9 to 10-7 m²/V·s through image processing of the recorded particle movement. Five organic sub-millimeter particles had charge densities in the range of -3.5 ~ 4.4 e/µm², and polyethersulfone particles showed extremely high mobilities. The surface charge of organic and inorganic particles is mainly generated by the dissociation of hydroxide groups or by the protonation to surface Lewis base oxygen atoms. [ABSTRACT FROM AUTHOR]

Polydimethylsiloxane (PDMS) has been extensively studied as a separation membrane due to the high permeability of gases and organicsolvents. Here we report 60-nm-thick PDMS membranes prepared by interfacial crosslinking of PDMS solution using N2-plasma. It was found that the presence of hydrocarbon in PDMS accelerates the crosslinking reaction, giving mechanically tough ultrathin membranes with swellable pores of 4 to 5 nm. Molecular modelling calculation suggested that dissociation of carbon-silicon bonds is the major pathway of crosslinking reaction. [ABSTRACT FROM AUTHOR]

The complicated chemical vapour deposition (CVD) is currently the most viable method of producing graphene. Most studies have extensively focused on chemical aspects either through experiments or computational studies. However, gas-phase dynamics in CVD reportedly plays an important role in improving graphene quality. Given that mass transport is the rate-limiting step for graphene deposition in atmospheric-pressure CVD (APCVD), the interfacial phenomena at the gas–solid interface (i.e., the boundary layer) are a crucial controlling factor. Accordingly, only by understanding and controlling the boundary-layer thickness can uniform full-coverage graphene deposition be achieved. In this study, a simplified computational fluid dynamics analysis of APCVD was performed to investigate gas-phase dynamics during deposition. Boundary-layer thickness was also estimated through the development of a customised homogeneous gas model. Interfacial phenomena, particularly the boundary layer and mass transport within it, were studied. The effects of Reynolds number on these factors were explored and compared with experimentally obtained results of the characterised graphene deposit. We then discussed and elucidated the important relation of fluid dynamics to graphene growth through APCVD. [ABSTRACT FROM AUTHOR]

High-density crosslinked polymer membranes several tens of nanometers thick were prepared by chemical vapor deposition (CVD) of propylamine (PA). Analysis by various methods showed that the densely crosslinked PA-CVD membranes had a composition of C 3. 0 H 4. 7 N 0. 8 O 0.4 , and contained amine, imine, vinyl, and carbonyl functional groups. Positron annihilation lifetime spectroscopy and alcohol-retention studies showed that the crosslinked membranes had pore sizes of 0.3–0.7 nm. Their porosity was about 10%, as estimated from water-absorption experiments. By appropriate choice deposition conditions, the average pore diameter could be selected, and the porosity could be tuned in the range 1–18%. A membrane with 0.56 nm pores showed a significant difference in the retention factors of C3 and C4 alcohols, for example, showing a 77% retention of tert -butanol, three times that of n -butanol. The thickness of PA-CVD membranes could be reduced to 10 nm, and the membrane showed a high retention performance for divalent ions, a resistance to pressures of more than 40 bars, and a water flux of up to 170 L m−2 h−1. This comprehensive investigation of the effects of the CVD parameters will permit tuning of the thickness, pore size, porosity, and density of the hydrophilic crosslinked membranes. [Display omitted] • Ultrathin hydrophilic crosslinked membranes were prepared from propylamine by PECVD. • Pore diameter controlled in the range 0.3–0.7 nm by tuning deposition parameters. • Membranes discriminated butanol isomers with a water flux of 170 L m−2 h−1@40 bar. • Membrane chemical structure characterized by PALS, NMR, FTIR, EA, and titration. • Effects of various CVD parameters assessed to develop design strategy of nanopores. [ABSTRACT FROM AUTHOR]

Although microporous carbons can perform well for CO2 separations under high pressure conditions, their energy-demanding regeneration may render them a less attractive material option. Here, we developed a large-pore mesoporous carbon with pore sizes centered around 20-30 nm using a templated technical lignin. During the soft-templating process, unique cylindrical supramolecular assemblies form from the copolymer template. This peculiar nanostructuring takes place due to the presence of polyethylene glycol (PEG) segments on both the Pluronic® template and the PEG-grafted lignin derivative (glycol lignin). A large increase in CO2 uptake occurs on the resulting large-pore mesoporous carbon at 270 K close to the saturation pressure (3.2 MPa), owing to capillary condensation. This phenomenon enables a CO2/CH4 selectivity  (SCO2/CH4, mol/mol) of 3.7 at 270 K and 3.1 MPa absolute pressure, and a swift pressure swing regeneration process with desorbed CO2 per unit pressure far outperforming a benchmark activated carbon (i.e., notably rapid decrease in the amount of adsorbed CO2 with decreasing pressure). We propose large-pore mesoporous carbons as a novel family of CO2 capture adsorbents, based on the phase-transition behavior shift of CO2 in the nanoconfined environment. This novel material concept may open new horizons for physisorptive CO2 separations with energy-efficient regeneration options., (© 2025 Wiley‐VCH GmbH.)