Self-assembling liquid crystals as building blocks to design nanoporous membranes suitable for molecular separations

Self-assembled nanostructured membranes with tunable pore size and shape from plant-derived materials

Nanostructured materials derived from sustainable sources are of interest as viable alternatives to traditional petroleum-derived sources in membrane applications due to environmental concerns. Here, we present the development of pore size-tunable nanostructured polymer membranes based on a plant-derived material. The membranes were fabricated using a tri-functional amine as the templating core species and a cross-linkable ligand synthesized from rose oil-derived citronellol. The self-assembly of a supramolecular complex between the template core and the ligand forms a hexagonally packed columnar (Colh) mesophase, the dimensions of which can be precisely controlled by changing the stoichiometric ratio between these constituents. Within the hexagonal mesophase stoichiometric range, the pore size of the nanostructured membranes can be tuned from 1.0 to 1.3 nm, with a step size of approximately 0.1 nm. The membranes exhibited a clear distinction in molecular size selectivity, as demonstrated by dye adsorption experiments. The membrane fabricated with a ligand-to-core ratio of 3 to 1 demonstrated shape-based selectivity, exhibiting a higher permeability for propeller-shaped penetrants and highlighting its potential for shape-selective transport. We anticipate that this straightforward approach, using plant-derived materials, can contribute to important sustainability aspects while enhancing the performance of current state-of-the-art nanostructured membranes by enabling precise control over pore size.

Lithium-ion batteries with fluorinated mesogen-based liquid-crystalline electrolytes: molecular design towards enhancing oxidation stability

Two-dimensional (2D) nanostructured liquid crystals containing fluorinated cyclohexylphenyl and cyclic carbonate moieties have been developed as quasi-solid-state self-organized electrolytes for safe lithium-ion batteries. We have designed lithium ion-conductive liquid-crystalline (LC) materials with fluorine substituents on mesogens for improved oxidation stability. Computational studies suggest that the fluorination of mesogens lowers the highest occupied molecular orbital (HOMO) level of LC molecules and improves their oxidation resistance as electrolytes. The LC molecule complexed with lithium bis(trifluoromethanesulfonyl)imide exhibits smectic A LC phases with 2D ion transport pathways over wide temperature ranges. Cyclic voltammetry measurements of the fluorinated mesogen-based LC electrolytes indicate that they are electrochemically stable above 4.0 V vs. Li/Li+. Lithium half-cells composed of fluorinated LC electrolytes show higher discharge capacity and coulombic efficiency than those containing non-fluorinated analogous LC molecules. Combining molecular dynamics simulations with the experimental results, it is revealed that the fluorination of the mesogen effectively enhances the electrochemical stability of the LC electrolytes without significantly disrupting ionic conductivities and the LC order.

Ionic nanoporous membranes from self-assembled liquid crystalline brush-like imidazolium triblock copolymers

There is a need to generate mechanically and thermally robust ionic nanoporous membranes for separation and fuel cell applications. Herein, we report a general approach to the preparation of ionic nanoporous membranes through custom synthesis, self-assembly, and subsequent chemical manipulations of ionic brush block copolymers. We synthesized polynorbornene-based triblock copolymers containing imidazolium cations balanced by counter anions in the central block, side-chain liquid crystalline units, and sidechain polylactide end blocks. This unique platform comprises: (1) imidazolium/bis(trifluoromethanesulfonyl)imide (TFSI) as the middle block, which has an excellent ion-exchange ability, (2) cyanobiphenyl liquid crystalline end block, a sterically hindered hydrophobic segment, which is chemically stable and immune to hydroxide attack, (3) polylactide brush-like units on the other end block that is easily etched under mild alkaline conditions and (4) a polynorbornene backbone, a lightly crosslinked system that offers mechanical robustness. These membranes retain their morphology before and after backbone crosslinking as well as etching of polylactide sidechains. The ion exchange performance and dimensional stability of these membranes were investigated by water uptake capability and swelling ratio. Moreover, the length of the carbon spacer in the imidazolium/TFSI central block moiety endowed the membrane with improved ionic conductivity. The ionic nanoporous materials are unusual due to their singular thermal, mechanical, alkaline stability and ion transport properties. Applications of these materials include electrochemical actuators, solid-state ionic nanochannel biosensors, and ion-conducting membranes.

An Up-to-Date Overview of Liquid Crystals and Liquid Crystal Polymers for Different Applications: A Review

Liquid crystals have been extensively used in various applications, such as optoelectronic devices, biomedical applications, sensors and biosensors, and packaging, among others. Liquid crystal polymers are one type of liquid crystal material, combining their intrinsic properties with polymeric flexibility for advanced applications in displays and smart materials. For instance, liquid crystal polymers can serve as drug nanocarriers, forming cubic or hexagonal mesophases, which can be tailored for controlled drug release. Further applications of liquid crystals and liquid crystal polymers include the preparation of membranes for separation processes, such as wastewater treatment. Furthermore, these materials can be used as ion-conducting membranes for fuel cells or lithium batteries due to their broad types of mesophases. This review aims to provide an overall explanation and classification of liquid crystals and liquid crystal polymers. Furthermore, the great potential of these materials relies on their broad range of applications, which are determined by their unique properties. Moreover, this study provides the latest advances in liquid crystal polymer-based membranes and their applications, focusing especially on fuel cells. Moreover, future directions in the applications of various liquid crystals are highlighted.

Electrochemical Detection of Selective Anion Transport through Subnanopores in Liquid-Crystalline Water Treatment Membranes

The anion-selective transport through subnanoporous liquid-crystalline (LC) water treatment membranes was quantitatively detected by the deposition and electrochemical analysis of the LC membrane on the GaN electrode. The time course of the capacitance and Warburg resistance of the LC membrane suggest that the interaction of the LC membrane with monovalent Cl- ions is distinctly different from that with SO42- ions. A continuous decay in capacitance suggests the condensation of Cl- ions in subnanopores, whereas the interaction between SO42- ions and the inner wall of subnanopores is much weaker. The chronoamperometry data further suggest that SO42- ions are transported through subnanoporous channels 10 times faster than Cl- ions. These results, together with the previous X-ray emission spectroscopy, suggest that SO42- ions, which possess similar hydrogen-bonded structures to the hydrogen-bonded networks inside the subnanopores, can exchange the associated water molecules and hop along the network of water molecules, but Cl- ions bind and accumulate inside subnanopores. The well-controlled supramolecular self-assembly of LC building blocks opens a large potential toward the fine adjustment of hydrogen-bonding networks in nanospace providing materials new functions, which cannot be realized by bulk water.

Effect of methyl methacrylate concentrations on surface and thermal analysis of composite polymer polymethylmethacrylates with mesogen reactive RM82

This research report of the synthesis of composite polymers from liquid crystal mesogen reactive (RM82) monomers with Methyl methacrylate (MMA). The purpose of this research is analysis the effect concentration of MMA on the surface and thermal of the composite polymer PMMA-RM82. The result of the morphological analysis of composite surfaces performed by polarization optical microscopy (POM) technique showed liquid crystal textures affected composition from two monomers. SEM images show that the surface of the RM82 liquid crystal has a shape resembling fibrous and blade-like crystals with a length of up to 10 μm (micrometers). Analysis thermal showed the heat released by the PMMA-RM82 increased with the increase in MMA weight percent. This affects the rapid crystallization process of PMMA-RM82 which of concentration MMA 30%-RM82 the heat released is almost twice as much as the heat released by MMA 5%-RM82. The absence of PMMA and RM82 peaks both endothermic and exothermic in PMMA-RM82 samples indicates that polymerization has occurred and a new product has formed. Analysis structure molecule by FTIR found that the IR spectral form of each variation in the weight percent of MMA was almost the same, but there was a spectral shift that showed that polymerization had occurred in PMMA-RM82 which was characterized by a reaction to the free radical C=C bond released by the photoinitiator. XRD pattern of composite PMMA-RM82 showed the peaks formed are located at scattering angles similar to RM82 but there is a decrease in intensity as the percent weight of MMA increases.

Aquatic Functional Liquid Crystals: Design, Functionalization, and Molecular Simulation

Aquatic functional liquid crystals, which are ordered molecular assemblies that work in water environment, are described in this review. Aquatic functional liquid crystals are liquid-crystalline (LC) materials interacting water molecules or aquatic environment. They include aquatic lyotropic liquid crystals and LC based materials that have aquatic interfaces, for example, nanoporous water treatment membranes that are solids preserving LC order. They can remove ions and viruses with nano- and subnano-porous structures. Columnar, smectic, bicontinuous LC structures are used for fabrication of these 1D, 2D, 3D materials. Design and functionalization of aquatic LC sensors based on aqueous/LC interfaces are also described. The ordering transitions of liquid crystals induced by molecular recognition at the aqueous interfaces provide distinct optical responses. Molecular orientation and dynamic behavior of these aquatic functional LC materials are studied by molecular dynamics simulations. The molecular interactions of LC materials and water are key of these investigations. New insights into aquatic functional LC materials contribute to the fields of environment, healthcare, and biotechnology.

Hydrogen-Bonded Structures of Water Molecules in Hydroxy-Functionalized Nanochannels of Columnar Liquid Crystalline Nanostructured Membranes Studied by Soft X-ray Emission Spectroscopy

Here, we report a synchrotron-based high-resolution soft X-ray emission spectroscopy study on hydrogen-bonded structures of water molecules in the self-organized, hydroxy-group-functionalized one-dimensional nanochannels of liquid crystalline nanostructured membranes. The water molecules confined in the uncharged hydroxy-functionalized nanochannels (which have a diameter of about 1.5 nm) exhibit hydrogen-bonded structures close to those of bulk liquid water, even directly interacting with diol groups. These hydrogen-bonded structures contrast with the more distorted hydrogen bonding of water molecules confined in self-organized channels with a diameter of 0.6 nm formed by an analogous nanostructured membrane with a cationic moiety, which was explained by the ability of the channel functional groups to donate and accept hydrogen bonds in a confined space and the nanochannel diameter.

Improvement strategies for oil/water separation based on electrospun SiO2 nanofibers

Oil spills and oily effluents from industry and daily life pose a great threat to all organisms in the ecosystem, while aggravating the problem of water scarcity, which has developed into a global challenge. Therefore, the development of advanced materials and technologies for oil/water separation has become a focus of attention. One-dimensional (1D) SiO2 nanofibers (SNFs) have become one of the most widely used inorganic nanomaterials in the past due to their stable chemical properties, excellent biocompatibility, and high temperature resistance etc. Meanwhile, electrospinning technique, as an emerging technology for treating oil/water emulsions, electrospun SNFs on this basis also has a number of advantages such as adjustable wettability, diverse structure and good connectivity. This review provides a systematic overview of the research progress of electrospun SNFs in different aspects. In this review, we first introduce the basic principles of electrospun SNFs, then focus on the design structures of various SNFs, propose corresponding strategies for the property improvement of SNFs, also analyze and consider the applications of SNFs. Finally, the challenges faced by electrospun SNFs in the field of oil/water separation are analyzed, and the future directions of electrospun SNFs are summarized and prospected.

Modified polymer membranes for the removal of pharmaceutical active compounds in wastewater and its mechanism-A review

Membrane technology can play a suitable role in removing pharmaceutical active compounds since it requires low energy and simple operation. Even though membrane technology has progressed for wastewater applications nowadays, modifying membranes to achieve the strong desired membrane performance is still needed. Thus, this study overviews a comprehensive insight into the application of modified polymer membranes to remove pharmaceutical active compounds from wastewater. Biotoxicity of pharmaceutical active compounds is first prescribed to gain deep insight into how membranes can remove pharmaceutical active compounds from wastewater. Then, the behavior of the diffusion mechanism can be concisely determined using mass transfer factor model that represented by β and B with value up to 2.004 g h mg-1 and 1.833 mg g-1 for organic compounds including pharmaceutical active compounds. The model refers to the adsorption of solute to attach onto acceptor sites of the membrane surface, external mass transport of solute materials from the bulk liquid to the membrane surface, and internal mass transfer to diffuse a solute toward acceptor sites of the membrane surface with evidenced up to 0.999. Different pharmaceutical compounds have different solubility and relates to the membrane hydrophilicity properties and mechanisms. Ultimately, challenges and future recommendations have been presented to view the future need to enhance membrane performance regarding fouling mitigation and recovering compounds. Afterwards, the discussion of this study is projected to play a critical role in advance of better-quality membrane technologies for removing pharmaceutical active compounds from wastewater in an eco-friendly strategy and without damaging the ecosystem.

Material Design Strategies for Recovery of Critical Resources from Water

Population growth, urbanization, and decarbonization efforts are collectively straining the supply of limited resources that are necessary to produce batteries, electronics, chemicals, fertilizers, and other important products. Securing the supply chains of these critical resources via the development of separation technologies for their recovery represents a major global challenge to ensure stability and security. Surface water, groundwater, and wastewater are emerging as potential new sources to bolster these supply chains. Recently, a variety of material-based technologies have been developed and employed for separations and resource recovery in water. Judicious selection and design of these materials to tune their properties for targeting specific solutes is central to realizing the potential of water as a source for critical resources. Here, the materials that are developed for membranes, sorbents, catalysts, electrodes, and interfacial solar steam generators that demonstrate promise for applications in critical resource recovery are reviewed. In addition, a critical perspective is offered on the grand challenges and key research directions that need to be addressed to improve their practical viability.

High-Flux Nanofibrous Composite Reverse Osmosis Membrane Containing Interfacial Water Channels for Desalination

A nanofibrous composite reverse osmosis (RO) membrane with a polyamide barrier layer containing interfacial water channels was fabricated on an electrospun nanofibrous substrate via an interfacial polymerization process. The RO membrane was employed for desalination of brackish water and exhibited enhanced permeation flux as well as rejection ratio. Nanocellulose was prepared by sequential oxidations of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) and sodium periodate systems and surface grafting with different alkyl groups including octyl, decanyl, dodecanyl, tetradecanyl, cetyl, and octadecanyl groups. The chemical structure of the modified nanocellulose was verified subsequently by Fourier transform infrared (FTIR), thermal gravimetric analysis (TGA), and solid NMR measurements. Two monomers, trimesoyl chloride (TMC) and m-phenylenediamine (MPD), were employed to prepare a cross-linked polyamide matrix, i.e., the barrier layer of the RO membrane, which integrated with the alkyl groups-grafted nanocellulose to build up interfacial water channels via interfacial polymerization. The top and cross-sectional morphologies of the composite barrier layer were observed by means of scanning electron microscopy (SEM), atomic force microscopy (AFM), and transmission electron microscopy (TEM) to verify the integration structure of the nanofibrous composite containing water channels. The aggregation and distribution of water molecules in the nanofibrous composite RO membrane verified the existence of water channels, demonstrated by molecular dynamics (MD) simulations. The desalination performance of the nanofibrous composite RO membrane was conducted and compared with that of commercially available RO membranes in the processing of brackish water, where 3 times higher permeation flux and 99.1% rejection ratio against NaCl were accomplished. This indicated that the engineering of interfacial water channels in the barrier layer could substantially increase the permeation flux of the nanofibrous composite membrane while retaining the high rejection ratio as well, i.e., to break through the trade-off between permeation flux and rejection ratio. Antifouling properties, chlorine resistance, and long-term desalination performance were also demonstrated to evaluate the potential applications of the nanofibrous composite RO membrane; remarkable durability and robustness were achieved in addition to 3 times higher permeation flux and a higher rejection ratio against commercial RO membranes in brackish water desalination.

Phase behaviour of mixtures of charged soft disks and spheres

We have investigated the phase behaviour of mixtures of soft disks (Gay-Berne oblate ellipsoids, GB) and soft spheres (Lennard-Jones, LJ) with opposite charge as a model of ionic liquid crystals and colloidal suspensions. We have used constant volume Molecular Dynamics simulations and fixed the stoichiometry of the mixture in order to have electroneutrality; three systems have been selected GB : LJ = 1 : 2, GB : LJ = 1 : 1 and GB : LJ = 2 : 1. For each system we have selected three values of the scaled point charge q* of the GB particles, namely 0.5, 1.0 and 2.0 (and a corresponding negative scaled charge of the LJ particles that depends on the stoichiometric ratio). We have found a very rich mesomorphism with the formation, as a function of the scaled temperature, of the isotropic phase, the discotic nematic phase, the hexagonal columnar phase and crystal phases. While the structure of the high temperature phases was similar in all systems, the hexagonal columnar phases exhibited a highly variable morphology depending on the scaled charge and stoichiometry. On the one hand, GB : LJ = 1 : 2 systems form lamellar structures, akin to smectic phases, with an alternation of layers of disks (exhibiting an hexagonal columnar phase) and layers of LJ particles (in the isotropic phase). On the other hand, for the 2 : 1 stoichiometry we observe the formation of a frustrated hexagonal columnar phase with an alternating tilt direction of the molecular axis. We rationalize these findings based on the structure of the neutral ion pair dominating the behaviour at low temperature and high charge.

Ion Transport in 2D Nanostructured π-Conjugated Thieno[3,2-b]thiophene-Based Liquid Crystal

Leveraging the self-assembling behavior of liquid crystals designed for controlling ion transport is of both fundamental and technological significance. Here, we have designed and prepared a liquid crystal that contains 2,5-bis(thien-2-yl)thieno[3,2-b]thiophene (BTTT) as mesogenic core and conjugated segment and symmetric tetra(ethylene oxide) (EO4) as polar side chains for ion-conducting regions. Driven by the crystallization of the BTTT cores, BTTT/dEO4 exhibits well-ordered smectic phases below 71.5 °C as confirmed by differential scanning calorimetry, polarized optical microscopy, temperature-dependent wide-angle X-ray scattering, and grazing incidence wide-angle X-ray scattering (GIWAXS). We adopted a combination of experimental GIWAXS and molecular dynamics (MD) simulations to better understand the molecular packing of BTTT/dEO4 films, particularly when loaded with the ion-conducting salt lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). Ionic conduction of BTTT/dEO4 is realized by the addition of LiTFSI, with the material able to maintain smectic phases up to r = [Li⁺]/[EO] = 0.1. The highest ionic conductivity of 8 × 10^-3 S/cm was attained at an intermedium salt concentration of r = 0.05. It was also found that ion conduction in BTTT/dEO4 is enhanced by forming a smectic layered structure with irregular interfaces between the BTTT and EO4 layers and by the lateral film expansion upon salt addition. This can be explained by the enhancement of the misalignment and configurational entropy of the side chains, which increase their local mobility and that of the solvated ions. Our molecular design thus illustrates how, beyond the favorable energetic interactions that drive the assembly of ion solvating domains, modulation of entropic effects can also be favorably harnessed to improve ion conduction.

From 1D Nanofibers to 3D Nanofibrous Aerogels: A Marvellous Evolution of Electrospun SiO2 Nanofibers for Emerging Applications

One-dimensional (1D) SiO2 nanofibers (SNFs), one of the most popular inorganic nanomaterials, have aroused widespread attention because of their excellent chemical stability, as well as unique optical and thermal characteristics. Electrospinning is a straightforward and versatile method to prepare 1D SNFs with programmable structures, manageable dimensions, and modifiable properties, which hold great potential in many cutting-edge applications including aerospace, nanodevice, and energy. In this review, substantial advances in the structural design, controllable synthesis, and multifunctional applications of electrospun SNFs are highlighted. We begin with a brief introduction to the fundamental principles, available raw materials, and typical apparatus of electrospun SNFs. We then discuss the strategies for preparing SNFs with diverse structures in detail, especially stressing the newly emerging three-dimensional SiO2 nanofibrous aerogels. We continue with focus on major breakthroughs about brittleness-to-flexibility transition of SNFs and the means to achieve their mechanical reinforcement. In addition, we showcase recent applications enabled by electrospun SNFs, with particular emphasis on physical protection, health care and water treatment. In the end, we summarize this review and provide some perspectives on the future development direction of electrospun SNFs.

Two-Photon Laser Microprinting of Highly Ordered Nanoporous Materials Based on Hexagonal Columnar Liquid Crystals

Nanoporous materials relying on supramolecular liquid crystals (LCs) are excellent candidates for size- and charge-selective membranes. However, whether they can be manufactured using printing technologies remained unexplored so far. In this work, we develop a new approach for the fabrication of ordered nanoporous microstructures based on supramolecular LCs using two-photon laser printing. In particular, we employ photo-cross-linkable hydrogen-bonded complexes, that self-assemble into columnar hexagonal (Colh) mesophases, as the base of our printable photoresist. The presence of photopolymerizable groups in the periphery of the molecules enables the printability using a laser. We demonstrate the conservation of the Colh arrangement and of the adsorptive properties of the materials after laser microprinting, which highlights the potential of the approach for the fabrication of functional nanoporous structures with a defined geometry. This first example of printable Colh LC should open new opportunities for the fabrication of functional porous microdevices with potential application in catalysis, filtration, separation, or molecular recognition.

Advanced Functional Liquid Crystals

Liquid crystals have been intensively studied as functional materials. Recently, integration of various disciplines has led to new directions in the design of functional liquid-crystalline materials in the fields of energy, water, photonics, actuation, sensing, and biotechnology. Here, recent advances in functional liquid crystals based on polymers, supramolecular complexes, gels, colloids, and inorganic-based hybrids are reviewed, from design strategies to functionalization of these materials and interfaces. New insights into liquid crystals provided by significant progress in advanced measurements and computational simulations, which enhance new design and functionalization of liquid-crystalline materials, are also discussed.

Hydrogen-Bonded Supramolecular Liquid Crystal Polymers: Smart Materials with Stimuli-Responsive, Self-Healing, and Recyclable Properties

Hydrogen-bonded liquid crystalline polymers have emerged as promising "smart" supramolecular functional materials with stimuli-responsive, self-healing, and recyclable properties. The hydrogen bonds can either be used as chemically responsive (i.e., pH-responsive) or as dynamic structural (i.e., temperature-responsive) moieties. Responsiveness can be manifested as changes in shape, color, or porosity and as selective binding. The liquid crystalline self-organization gives the materials their unique responsive nanostructures. Typically, the materials used for actuators or optical materials are constructed using linear calamitic (rod-shaped) hydrogen-bonded complexes, while nanoporous materials are constructed from either calamitic or discotic (disk-shaped) complexes. The dynamic structural character of the hydrogen bond moieties can be used to construct self-healing and recyclable supramolecular materials. In this review, recent findings are summarized, and potential future applications are discussed.

Anisotropic Dyes Adsorption by Templated Smectic Nanoporous Polymer Films: Pore Size vs Pore Charges Affecting the Adsorption

Selective 2-dimentional (2D) nanoporous polymer films have been developed by a templating method based on hydrogen-bonding supramolecular liquid crystals (LCs) containing benzoic acid and pyridine groups (6OBA·NC6·C6H). The smectic lamellar...

Liquid Crystals: Versatile Self-Organized Smart Soft Materials

Smart soft materials are envisioned to be the building blocks of the next generation of advanced devices and digitally augmented technologies. In this context, liquid crystals (LCs) owing to their responsive and adaptive attributes could serve as promising smart soft materials. LCs played a critical role in revolutionizing the information display industry in the 20th century. However, in the turn of the 21st century, numerous beyond-display applications of LCs have been demonstrated, which elegantly exploit their controllable stimuli-responsive and adaptive characteristics. For these applications, new LC materials have been rationally designed and developed. In this Review, we present the recent developments in light driven chiral LCs, i.e., cholesteric and blue phases, LC based smart windows that control the entrance of heat and light from outdoor to the interior of buildings and built environments depending on the weather conditions, LC elastomers for bioinspired, biological, and actuator applications, LC based biosensors for detection of proteins, nucleic acids, and viruses, LC based porous membranes for the separation of ions, molecules, and microbes, living LCs, and LCs under macro- and nanoscopic confinement. The Review concludes with a summary and perspectives on the challenges and opportunities for LCs as smart soft materials. This Review is anticipated to stimulate eclectic ideas toward the implementation of the nature's delicate phase of matter in future generations of smart and augmented devices and beyond.

Towards a High-Flux Separation Layer from Hexagonal Lyotropic Liquid Crystals for Thin-Film Composite Membranes

Hexagonal lyotropic liquid crystals (HLLC) with uniform pore size in the range of 1~5 nm are highly sought after as promising active separation layers of thin-film composite (TFC) membranes, which have been confirmed to be efficient for water purification. The potential interaction between an amphiphile-based HLLC layer and the substrate surface, however, has not been fully explored. In this research, hydrophilic and hydrophobic microporous polyvinylidene fluoride (PVDF) substrates were chosen, respectively, to prepare TFC membranes with the active layers templated from HLLC, consisting of dodecyl trimethylammonium bromide, water, and a mixture of poly (ethylene glycol) diacrylate and 2-hydroxyethyl methacrylate. The pore size of the active layer was found to decrease by about 1.6 Å compared to that of the free-standing HLLC after polymerization, but no significant difference was observable by using either hydrophilic or hydrophobic substrates (26.9 Å vs. 27.1 Å). The water flux of the TFC membrane with the hydrophobic substrate, however, was higher than that with the hydrophilic one. A further investigation confirmed that the increase in water flux originated from a much higher porosity was due to the synergistic effect of the hydrophilic HLLC nanoporous material and the hydrophobic substrate.