Janus Superiority of Membranes in Chemical Engineering and Beyond.

Janus configurations, characterized by their inherent asymmetry, enable directional mass transfer in membrane materials that drive novel and energy-efficient chemical processes. This Janus superiority spans applications from nanoscale molecular and ionic transport to macro-scale separation systems with asymmetric spatial architectures. This review provides an analysis of the material foundations including design principles, structure regulation, and scalability challenges underlying Janus membranes.

Siphon-driven all-in-one fabric evaporators for multi-purpose treatment of hypersaline oily wastewater.

Hypersaline oily wastewater from industrial processes poses significant environmental challenges, but traditional treatment methods struggle with issues like oil contamination, membrane fouling, and incomplete oil/salt separation. In this work, we developed a siphon-driven all-in-one fabric evaporator (SAFE) that integrates siphon-driven separation with solar-driven evaporation to address these issues effectively. The photothermal fabrics are facilely fabricated by depositing polydopamine on polypropylene non-woven fabrics, imparting oil repellence, light-to-heat conversion, and hydrophilicity.

Ultrathin and Stable Ionic Liquid Membranes with Bio-Inspired Interlocking Architecture for CO Separation.

The growing demand for energy-efficient carbon capture has spurred significant advancements in supported ionic liquid membranes (SILMs), which utilize ionic liquid (IL) with high CO solubility for continuous gas purification processes. However, conventional SILMs are hindered by a persistent limitation: thick IL layers (> 50 µm) significantly reduce CO permeance to below 1 GPU, while also causing mechanical failure under prolonged operational pressure. Inspired by the interlocking elytra of Tenebrionidae beetles, which use microscale "teeth" to withstand mechanical stress, locked ionic liquid membranes (LILMs) are engineered by composeing two interpenetrating polyamide nanofilms with biomimetic protrusions.

Janus channel of membranes enables concurrent oil and water recovery from emulsions.

Existing separation technologies struggle to recover oil and water concurrently from surfactant-stabilized emulsions to achieve the goal of near-zero liquid discharge. We present a Janus channel of membranes (JCM) that features a confined architecture constructed of a pair of hydrophilic and hydrophobic membranes, which allows for concurrent, highly efficient recovery of oil and water from surfactant-stabilized emulsions. The confined Janus channel can amplify the interplay of the membrane pair through a feedback loop that involves enrichment and demulsification.

Tailoring Polyamide Nanofiltration Membranes by Switching Charge of Nanocellulose Interlayers.

The interlayer strategy has emerged as an effective approach for modulating the interfacial polymerization process and improving the permeability and selectivity of polyamide membranes. However, the underlying mechanisms by which charged interlayers influence the interfacial polymerization process remain inadequately understood. In this study, we utilized two distinct charged cellulose nanofibers, namely, carboxylated cellulose (⊖-CNF) and quaternized cellulose ([Formula: see text]-CNF), as interlayers to regulate the interfacial polymerization process.

Leveraging Janus Substrates as a Confined "Interfacial Reactor" to Synthesize Ultrapermeable Polyamide Nanofilms.

Porous substrates act as open "interfacial reactors" during the synthesis of polyamide composite membranes via interfacial polymerization. However, achieving a thin and dense polyamide nanofilm with high permeance and selectivity is challenging when using a conventional substrate with uniform wettability. To overcome this limitation, we propose the use of Janus porous substrates as confined interfacial reactors to decouple the local monomer concentration from the total monomer amount during interfacial polymerization.

Supergravity-Steered Generic Manufacturing of Nanosheets-Embedded Nanocomposite Hydrogel with Highly Oriented, Heterogeneous Architecture.

Designing nanocomposite hydrogels with oriented nanosheets has emerged as a promising toolkit to achieve preferential performances that go beyond their disordered counterparts. Although current fabrication strategies via electric/magnetic force fields have made remarkable achievements, they necessitate special properties of nanosheets and suffer from an inferior orientation degree of nanosheets. Herein, a facile and universal approach is discovered to elaborate MXene-based nanocomposite hydrogels with highly oriented, heterogeneous architecture by virtue of supergravity to replace conventional force fields.

Double charge flips of polyamide membrane by ionic liquid-decoupled bulk and interfacial diffusion for on-demand nanofiltration.

Fine design of surface charge properties of polyamide membranes is crucial for selective ionic and molecular sieving. Traditional membranes face limitations due to their inherent negative charge and limited charge modification range. Herein, we report a facile ionic liquid-decoupled bulk/interfacial diffusion strategy to elaborate the double charge flips of polyamide membranes, enabling on-demand transformation from inherently negative to highly positive and near-neutral charges.

Harmonic amide bond density as a game-changer for deciphering the crosslinking puzzle of polyamide.

It is particularly essential to analyze the complex crosslinked networks within polyamide membranes and their correlation with separation efficiency for the insightful tailoring of desalination membranes. However, using the degree of network crosslinking as a descriptor yields abnormal analytical outcomes and limited correlation with desalination performance due to imperfections in segmentation and calculation methods. Herein, we introduce a more rational parameter, denoted as harmonic amide bond density (HABD), to unravel the relationship between the crosslinked networks of polyamide membranes and their desalination performance.

Supported Ionic Liquid Membrane with Highly-permeable Polyamide Armor by In Situ Interfacial Polymerization for Durable CO Separation.

Supported ionic liquid membranes (SILMs), owing to their capacities in harnessing physicochemical properties of ionic liquid for exceptional CO solubility, have emerged as a promising platform for CO extraction. Despite great achievements, existing SILMs suffer from poor structural and performance stability under high-pressure or long-term operations, significantly limiting their applications. Herein, a one-step and in situ interfacial polymerization strategy is proposed to elaborate a thin, mechanically-robust, and highly-permeable polyamide armor on the SILMs to effectively protect ionic liquid within porous supports, allowing for intensifying the overall stability of SILMs without compromising CO separation performance.

Room-temperature endogenous lubricant-infused slippery surfaces by evaporation induced phase separation.

We present a novel approach to fabricate endogenous slippery lubricant-infused porous surfaces (eSLIPS) at room temperature using an evaporation-induced phase separation process. The ternary coating system, comprising ethylene-propylene copolymer, caprylyl methicone, and -hexane, forms a porous structure infiltrated with lubricant, resulting in surfaces with remarkable anti-fouling and anti-icing properties.

Design of Photothermal "Ion Pumps" for Achieving Energy-Efficient, Augmented, and Durable Lithium Extraction from Seawater.

Extracting lithium from seawater has emerged as a disruptive platform to resolve the issue of an ever-growing lithium shortage. However, achieving highly efficient and durable lithium extraction from seawater in an energy-efficient manner is challenging, as imposed by the low concentration of lithium ions (Li) and high concentration of interfering ions in seawater. Here, we report a facile and universal strategy to develop photothermal "ion pumps" (PIPs) that allow achieving energy-efficient, augmented, and durable lithium extraction from seawater under sunlight.

Solid-state, liquid-free ion-conducting elastomers: rising-star platforms for flexible intelligent devices.

Soft ionic conductors have emerged as a powerful toolkit to engineer transparent flexible intelligent devices that go beyond their conventional counterparts. Particularly, due to their superior capacities of eliminating the evaporation, freezing and leakage issues of the liquid phase encountered with hydrogels, organohydrogels and ionogels, the emerging solid-state, liquid-free ion-conducting elastomers have been largely recognized as ideal candidates for intelligent flexible devices. However, despite their extensive development, a comprehensive and timely review in this emerging field is lacking, particularly from the perspective of design principles, advanced manufacturing, and distinctive applications.

Polyamide nanofiltration membranes by vacuum-assisted interfacial polymerization: Broad universality of Substrate, wide window of monomer concentration and high reproducibility of performance.

Vacuum assistance is used for filtering solid substances onto porous substrates to create composite membranes typically. However, the potential of this approach has rarely been assessed in facilitating the distribution of liquids within those porous substrates to fabricate composite membranes in typical interfacial polymerization. In this work, we demonstrate the advantages of vacuum-assisted interfacial polymerization (VAIP) in terms of substrate universality, monomer concentration range, and performance reproducibility in the fabrication of polyimide nanofiltration membranes.

Interfacial polymerization at unconventional interfaces: an emerging strategy to tailor thin-film composite membranes.

Interfacial polymerization is a well-known process to synthesize separation layers for thin film composite membranes at an immiscible organic liquid-aqueous liquid interface. The organic-aqueous interface determines the diffusion dynamics of monomers and the chemical environment for polymerization, exerting a critical influence on the formation of polymer thin films. This review summarizes recent advances in tailoring interfacial polymerization using interfaces beyond the conventional alkane-water interface to achieve high-performance separation films with designed structures.

Wood-based capillary enhancers for accelerated moisture capture and solar-powered release.

The pressing need to address the global water crisis has spurred research efforts toward exploring alternative sources and technologies, and harvesting atmospheric water from the humid air emerges as a promising solution. Liquid desiccants, known for their high absorption capacity, have been widely utilized for moisture capture, but their water yield is mainly restricted by sluggish adsorption and desorption dynamics. To address this limitation, we present a facile strategy to promote the absorption/desorption dynamics of moisture by virtue of capillary transport and enlarged interfaces in a photothermal wood enhancer.

Photothermal Janus fabrics enabling persistent directional sweat-wicking in personal wet-thermal management.

Directional sweat-wicking by Janus fabrics has gained substantial attention in promoting personal wet-thermal management for optimal human comfort. During intense physical exercise, excessive sweating can cause the flooding of fabrics and weaken their wicking capabilities once the inner capillary channels are saturated. To address this issue, we develop a photothermal Janus fabric through a facile polydopamine (PDA) deposition followed by single-sided spray-coating of hydrophobic polydimethylsiloxane (PDMS).

Solar-Driven Evaporators with Thin-Film-Composite Architecture Inspired by Plant Roots for Treating Concentrated Nano-/Submicrometer Emulsions.

Oil/water separation by porous materials has received growing interest over the past years since the ever-increasing oily wastewater discharges seriously threaten our living environment. Purification of nano-sized and concentrated emulsions remains a big challenge because of the sharp flux decline by blocking the pores and fouling the surfaces of those porous materials. Herein, we propose a solar-driven evaporator possessing thin-film-composite architecture to deal with these two bottlenecks.

Metal-Polyphenol Coordination at the Aqueous Contra-diffusion "Interface": A Green Way to High-Performance Iron(III)/Tannic Acid Thin-Film-Composite Nanofiltration Membranes.

Thin-film-composite (TFC) nanofiltration membranes have found wide uses in environment remediation and industrial separation. There is a growing trend to avoid the use of organic solvents and toxic chemicals during membrane fabrication. Therefore, the aqueous fabrication of TFC membranes receives considerable interest as a green and sustainable process.

Suspended Membrane Evaporators Integrating Environmental and Solar Evaporation for Oily Wastewater Purification.

Solar-driven evaporation is promising in oily wastewater treatment, in particular for emulsions, but conventional evaporators suffer from pore blocking by residual oil or contamination by volatile oil compounds in the condensed water. In the current research, we develop a suspended membrane evaporator integrating solar evaporation with oil-in-water emulsion separation. The heating and evaporating interface is separated from the rejecting interface to avoid oil escape and improve heat management.

Sandwich-Structured Photothermal Wood for Durable Moisture Harvesting and Pumping.

Moisture capture coupled with photothermal regeneration provides an alternative and sustainable way to acquire fresh water. Composite moisture absorbents based on hygroscopic salts are environmentally friendly, economically feasible, and of high efficiency but suffer from the unavoidable desiccant leakage during absorption and evaporation-induced salt accumulation on material surfaces during desorption. In this study, we develop a superhydrophobic-hydrophilic-hydrophobic photothermal wood embedded with CaCl to promote the durability of the absorbents.

Brushable Lubricant-Infused Porous Coating with Enhanced Stability by One-Step Phase Separation.

Slippery lubricant-infused porous surface (SLIPS) is a promising solution to undesired adhesion. Unfortunately, the complicated fabrication process and limited coating area block its practical applications. Herein, we report a one-step strategy to fabricate polypropylene-based SLIPS coatings through thermally induced phase separation, in which the lubricant is infiltrated within a polymer network formed during cooling.

Unraveling the Interfacial Structure-Performance Correlation of Flexible Metal-Organic Framework Membranes on Polymeric Substrates.

Pure metal-organic framework (MOF) layers deposited on porous supports are important candidates for molecular sieving membranes, but their performance usually deviates from theoretical estimations. Here, we combine step-wise scanning electron microscopy imaging, time-resolved synchrotron X-ray scattering, terahertz infrared spectroscopy, and density functional theory calculation to investigate the ZIF-8 membrane formation on two types (polydopamine and TiO) of functionalized porous supports. Though molecular sieving of ZIF-8 membranes for smaller gases (He, H, and CO) can be achieved with both types of functionalized supports, we unravel that the strong interaction between MOF and polydopamine can disrupt the formation of "perfect" MOF crystals at the interface, leading to a "contracted" MOF structure with partially uncoordinated imidazolate ligands.

Atomic layer deposition for membrane interface engineering.

In many applications, interfaces govern the performance of membranes. Structure, chemistry, electrostatics, and other properties of interfaces can dominate the selectivity, flux, fouling resistance, and other critical aspects of membrane functionality. Control over membrane interfacial properties, therefore, is a powerful means of tailoring performance.