Janus membranes are an emerging class of materials having opposing properties at an interface. This structure results in selective and often novel transport characteristics. In this Minireview, a ...definition of the Janus membrane, beyond merely asymmetric materials, is introduced and common fabrication strategies are outlined. Also presented are current and potential applications in directional transport, switchable permeation, and performance optimization with detailed mechanisms.
Crossing over: Janus membranes have received widespread interest over the past years. In this Minireview, a special definition of a Janus membrane is proposed and common fabrication methods of such membranes are outlined. Also summarized are the current and potential applications of Janus membranes in directional transport, switchable permeation, and performance optimization.
Polymerization at the liquid–liquid interface has attracted much attention for synthesizing ultrathin polymer films for molecular sieving. However, it remains a major challenge to conduct this ...process outside the alkane–water interface since it not only suffers water‐caused side reactions but also is limited to water‐soluble monomers. Here, we report the interfacial polymerization at the alkane/ionic liquid interface (IP@AILI) where the ionic liquid acts as the universal solvent for diversified amines to synthesize task‐specific polyamide nanofilms. We propose that IP@AILI occurs when acyl chloride diffuses from the alkane into the ionic liquid instead of being triggered by the diffusion of amines as in the conventional alkane–water system, which is demonstrated by thermodynamic partitioning and kinetic monitoring. The prepared polyamide nanofilms with precisely adjustable pore sizes display unprecedented permeability and selectivity in various separation processes.
Interfacial polymerization at the alkane/ionic liquid interface has been designed. The extendibility, designability, and controllability brought by the ionic liquid replace the instability and low solubility caused by water in conventional polymerization. The polyamide nanofilms synthesized at the new delicate water‐insoluble monomer interfaces possess adjustable pore size and exhibit unprecedented performance in various separation applications.
Fast and efficient cleanup of crude oil spills is still a global challenge because most of the crude oils are highly viscous and lowly fluid. Herein, a kind of polydimethylsiloxane‐decorated wood ...carbon sponges (PDMS@WCS) with desirable compressibility and hydrophobicity for the fast adsorption and enhanced recovery of crude oil via the promotion of Joule‐heating and photothermal effect is reported. Moreover, the PDMS@WCS can be compressed and released at a constant strain of 50% for over times without structural damage due to the protection of PDMS coating. Thus, the adsorbed crude oil can be facilely excluded from PDMS@WCS under external pressure to show enhanced recovery.
Compressible and hydrophobic wood carbon sponges are elegantly fabricated from natural balsa woods and applied for the rapid recovery of high viscosity crude oil via the promotion of Joule‐heating and photothermal effect. Moreover, they possess a vertical porous structure inherited from natural wood that can greatly reduce the transport path of crude oil and increase the oil adsorption rate.
Producing affordable freshwater has been considered as a great societal challenge, and most conventional desalination technologies are usually accompanied with large energy consumption and thus ...struggle with the trade‐off between water and energy, i.e., the water–energy nexus. In recent decades, the fast development of state‐of‐the‐art photothermal materials has injected new vitality into the field of freshwater production, which can effectively harness abundant and clean solar energy via the photothermal effect to fulfill the blue dream of low‐energy water purification/harvesting, so as to reconcile the water–energy nexus. Driven by the opportunities offered by photothermal materials, tremendous effort has been made to exploit diverse photothermal‐assisted water purification/harvesting technologies. At this stage, it is imperative and important to review the recent progress and shed light on the future trend in this multidisciplinary field. Here, a brief introduction of the fundamental mechanism and design principle of photothermal materials is presented, and the emerging photothermal applications such as photothermal‐assisted water evaporation, photothermal‐assisted membrane distillation, photothermal‐assisted crude oil cleanup, photothermal‐enhanced photocatalysis, and photothermal‐assisted water harvesting from air are summarized. Finally, the unsolved challenges and future perspectives in this field are emphasized. It is envisioned that this work will help arouse future research efforts to boost the development of solar‐driven low‐energy water purification/harvesting.
As a promising candidate to reconcile the water–energy nexus, solar‐driven low‐energy water purification/harvesting technologies have attracted increased attention. The latest progress, challenges, and prospective of engineering solar‐driven photothermal materials/devices and their potential applications are discussed, stimulating new thinking on the exploration of advanced technologies to fulfill the blue dream of low‐energy water purification/harvesting.
Mussel‐inspired polydopamine (PDA) deposition offers a promising route to fabricate multifunctional coatings for various materials. However, PDA deposition is generally a time‐consuming process, and ...PDA coatings are unstable in acidic and alkaline media, as well as in polar organic solvents. We report a strategy to realize the rapid deposition of PDA by using CuSO4/H2O2 as a trigger. Compared to the conventional processes, our strategy shows the fastest deposition rate reported to date, and the PDA coatings exhibit high uniformity and enhanced stability. Furthermore, the PDA‐coated porous membranes have excellent hydrophilicity, anti‐oxidant properties, and antibacterial performance. This work demonstrates a useful method for the environmentally friendly, cost‐effective, and time‐saving fabrication of PDA coatings.
Mussel‐inspired surfaces: A facile and robust approach to rapidly construct polydopamine (PDA) coatings on various substrates is presented. The CuSO4/H2O2‐triggered PDA coatings show high uniformity, enhanced stability, excellent hydrophilicity, antioxidant ability, and antibacterial performance.
Membrane fouling is one of the most severe problems restricting membrane separation technology for wastewater treatment. This work reports a photocatalytic nanofiltration membrane (NFM) with ...self‐cleaning property fabricated using a facile biomimetic mineralization process. In this strategy, a polydopamine (PDA)/polyethyleneimine (PEI) intermediate layer is fabricated on an ultrafiltration membrane via a co‐deposition method followed by mineralization of a photocatalytic layer consisting of β‐FeOOH nanorods. The PDA–PEI layer acts both as a nanofiltration selective layer and an intermediate layer for anchoring the β‐FeOOH nanorods via strong coordination complexes between Fe3+ and catechol groups. In visible light, the β‐FeOOH layer exhibits efficient photocatalytic activity for degrading dyes through the photo‐Fenton reaction in the presence of hydrogen peroxide, endowing the NFM concurrently with effective nanofiltration performance and self‐cleaning capability. Moreover, the mineralized NFMs exhibit satisfactory stability under simultaneous filtration and photocatalysis processing, showing great potential in advanced wastewater treatment.
A photocatalytic nanofiltration membrane (NFM) with self‐cleaning capability is fabricated via a facile biomimetic mineralization process. In visible light, this membrane exhibits efficient photocatalytic activity for degrading dyes through the photo‐Fenton reaction concurrently with effective nanofiltration performance. The as‐prepared NFM shows great potential in advanced textile wastewater treatment with satisfactory stability.
Mussel-inspired chemistry has become an ideal platform to engineer a myriad of functional materials, but fully understanding the underlying adhesion mechanism is still missing. Particularly, one of ...the most pivotal questions is whether catechol still plays a dominant role in molecular-scale adhesion like that in mussel adhesive proteins. Herein, for the first time, we reveal an unexplored adhesion mechanism of mussel-inspired chemistry that is strongly dictated by 5,6-dihydroxyindole (DHI) moieties, amending the conventional viewpoint of catechol-dominated adhesion. We demonstrate that polydopamine (PDA) delivers an unprecedented adhesion of 71.62 mN m
−1
, which surpasses that of many mussel-inspired derivatives and is even 121-fold higher than that of polycatechol. Such a robust adhesion mainly stems from a high yield of DHI moieties through a delicate synergy of leading oxidation and subsidiary cyclization within self-polymerization, allowing for governing mussel-inspired adhesion by the substituent chemistry and self-polymerization manner. The adhesion mechanisms revealed in this work offer a useful paradigm for the exploitation of functional mussel-inspired materials.
A 5,6-dihydroxyindole (DHI)-dominated mechanism in the interfacial adhesion of mussel-inspired chemistry is first proposed and demonstrated by the fusion of
in situ
force measurements with molecular-scale simulations.
Over the past decades, polymer membranes are becoming more and more compelling due to their growing demand in environment, energy and health fields. Many efforts have been devoted to improve the ...membrane performance and extend their application via the methodology of surface engineering. One of the most promising strategies is mussel-inspired chemistry, which has become a powerful tool in membrane fabrication and modification because of its universality and versatility. Considering the increasing interest and advances in this field, we present this review regarding mussel-inspired chemistry in the surface engineering of polymer membranes. The adhesion mechanism and properties of polydopamine (as a representative) are briefly outlined at the beginning. Then detailed elaboration is followed on the applications of mussel-inspired chemistry in the surface science and technology of membranes. Catecholamines can be directly deposited on the membrane surface, act as an interface layer for post-modification, serve as a surface component of membrane and pre-decorate polymers for membrane modification or fabrication. Finally, we summarize recent research progress and give a further perspective of the mussel-inspired catecholamine in membrane science and technology.
Display omitted
•Critical review of mussel-inspired chemistry in membrane surface engineering.•Illustration of adhesion mechanisms and properties of polydopamine.•Outline of applications both in membrane fabrication and surface modification.•Great potentials in separation membranes with high-performance and multi-function.
Janus membranes show great promise toward various applications and are undergoing a fast‐paced development in materials science. The asymmetric surface engineering on surface wettability, layer ...thickness, and pore structure enables Janus membranes with superiority in mass transport over conventional membranes. This review aims to provide an overview on the role of asymmetric surface engineering in membrane fabrication, structure control, and property tuning. The relationship between asymmetric surface engineering and performance optimization of Janus membranes is then elucidated based on an understanding of the underlying mass transport mechanism for target applications. Finally, current challenges in this field are highlighted, hopefully inspiring more researches to address the controllability and tunability of surface engineering for Janus membranes in future.
Janus membranes show great promise toward various applications in materials science via surface engineering. A review of the influcence of asymmetric surface engineering on the membrane fabrication, structure tuning, and performane regulation is provided based on an understanding of the underlying mass transport principle. Finally, current challenges regarding the performance optimization of Janus membranes through controllable surface engineering are highlighted.
Dopamine: Just the Right Medicine for Membranes Yang, Hao‐Cheng; Waldman, Ruben Z.; Wu, Ming‐Bang ...
Advanced functional materials,
February 21, 2018, Volume:
28, Issue:
8
Journal Article
Peer reviewed
Open access
Mussel‐inspired chemistry has attracted widespread interest in membrane science and technology. Demonstrating the rapid growth of this field over the past several years, substantial progress has been ...achieved in both mussel‐inspired chemistry and membrane surface engineering based on mussel‐inspired coatings. At this stage, it is valuable to summarize the most recent and distinctive developments, as well as to frame the challenges and opportunities remaining in this field. In this review, recent advances in rapid and controllable deposition of mussel‐inspired coatings, dopamine‐assisted codeposition technology, and photoinitiated grafting directly on mussel‐inspired coatings are presented. Some of these technologies have not yet been employed directly in membrane science. Beyond discussing advances in conventional membrane processes, emerging applications of mussel‐inspired coatings in membranes are discussed, including as a skin layer in nanofiltration, interlayer in metal‐organic framework based membranes, hydrophilic layer in Janus membranes, and protective layer in catalytic membranes. Finally, some critical unsolved challenges are raised in this field and some potential pathways are proposed to address them.
Mussel‐inspired polydopamine is a rising star in membrane science and technology. The most recent advances in polydopamine deposition are highlighted and summarized, as well as its emerging applications in nanofiltration, metal‐organic framework composite membranes, Janus membranes, and photocatalytic membranes.
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