Single-layer Membrane Research Articles

An ultrasensitive flexible force sensor with nature-inspired minimalistic architecture to achieve a detection resolution and threshold of 1 mN for underwater applications

Highly sensitive flexible force sensors enable precise detection of underwater signals for monitoring biological activity, environmental conditions, and vehicle movement. Multilayer stack assembly and micro/nano structure array are often seen in most force/pressure sensors which are toughly hard to control the interlayer spacing and micro/nano structures alignment precisely, resulting in poor consistency and stability. Herein, we first reported a new force sensor with a nature-inspired minimalistic architecture, addressing such issues in an elegant and surprising approach by using a single-layer arched functional membrane with one microgroove. Inspired by the scorpions’ slit sensilla and mantis’ campaniform sensilla, a highly sensitive and waterproof flexible force sensor was fabricated. It is demonstrated that the force sensor has a sensitivity of 27.6 N−1, a high force resolution (1 mN), a fast response time of 70 ms, excellent stability over 5000 cycles and linearity (0.996), and a small force detection limit (≤ 1 mN), showing great potential in underwater environment sensing and motion monitoring of vehicles. This novel but minimalistic architecture provides a new direction in the development of sensors with advanced performance.

Permeability of gas molecules through sub-nanometer nitrogen-terminated porous graphene membranes: A DFT study

We present a systematic theoretical investigation of gas permeability through single-layer nanoporous graphene membranes with N-terminated (pyridinic and mixed pyridinic/pyrrolic) pores for He, H2, N2, O2, CO, CO2, H2O, and CH4. Our study is based on density functional theory transition-state calculations and the kinetic theory of gasses. We systematically evaluate pores of varying sizes and shapes up to 5.7 Å in diameter. According to our findings, membranes with pores in the size regime (4.5 Å - 5.0 Å) may exhibit industrially acceptable permeance to several gas molecules and advanced selectivity. Notably, we found that, among a few others, a pore with the same topological features at the pore boundary as those of the characteristic pore of g-C3N4 carbon nitride, is particularly promising. In addition, membranes with larger pores, ∼5.5 Å - 5.7 Å, can effectively separate CH4 from the other molecules. Our findings support the advanced potential of single-layer graphene membranes with nitrogen-terminated sub-nanometer pores, for gas separation applications.

Simulation analysis of a photonic crystal fiber refractive index sensor based on a double-layer film structure and surface plasmon resonance technology

A photonic crystal fiber surface plasmon resonance sensor based on a double-layer membrane structure is designed and analyzed. In the simple sensing structure with only one air hole size, TiO2 and Au layers with specific thicknesses are sequentially coated on the optical fiber to form a double-layer structure. The sensing characteristics of the double-layer membrane structure are studied by the finite element method. Compared to the single-layer membrane structure, the double-layer membrane sensor has significant sensing properties such as a better wavelength sensitivity and a smaller full width at half maximum in the loss spectrum. In the refractive index range between 1.37 and 1.43, the maximum wavelength sensitivity and average wavelength sensitivity of the sensor are 19,900 nm/RIU and 7417 nm/RIU, respectively, and the resolution can be up to 5.03×10−6RIU. The proposed photonic crystal fiber optic sensor achieves high performance with a simpler sensing structure than previous photonic crystal fiber optic sensors, and eliminates the step of polishing, which will greatly reduce the difficulty of actual fabrication and the error due to uneven polishing. The results show that the photonic crystal fiber optic sensor with a double-layer membrane structure has excellent performance. Due to its high sensitivity and resolution, it has great potential for applications in environmental monitoring, biosensing and chemical sensing.

Mechanical anisotropy on reduced ballistic limit of phosphorene by cone wave reflection：A computational study

Two-dimensional materials, such as phosphorene, exhibit exceptional electrical and mechanical properties, offering promising prospects for both electronic and mechanical applications. To design more mechanically reliable devices using phosphorene, exploring its mechanical performance, especially impact resistance, is necessary. Here, coarse-grained molecular dynamics simulations are presented to study the mechanical responses of phosphorene under ballistic impact. Interestingly, size-dependent behaviors have been observed, which could be attributed to a coupling effect of cone wave reflection and membrane size. Owing to significant differences in Young’s modulus between the armchair and zigzag direction in phosphorene, mechanical wave propagation exhibits substantial anisotropy in a single-layer phosphorene membrane. A critical membrane size has been identified, below which cone wave reflections from the boundaries can induce perforation: a phenomenon particularly relevant to micro-ballistic testing of two-dimensional material membranes. The effect of boundary shape on reduction in ballistic limit has been studied, in which all the phosphorene sheets in the study are elliptical while the axial ratio of the ellipses is varied from 0.54 to 1.85. The axial ratio 0.69 is proven to maximize the strain amplification induced by cone wave reflection, thus leading to the biggest reduction in ballistic impact for phosphorene. A unitless indicator based on atomic Green-Lagrange strain has been proposed, which can effectively quantify the boundary shape effect on the reduced ballistic limit. Our findings provide timely guidance for the design of future nanodevices using phosphorene with high impact resistance.

Preparation of a membrane-sealed cell for studying catalyst nanoparticles in flowing gas with high vacuum x-ray photoelectron spectrometer.

Here a sealing-style x-ray photoelectron spectroscopy study of the surface of a 1.0 wt. %Ni/TiO2 nanoparticle catalyst in a flowing mixture of CO and O2 at 1bar was performed with a graphene membrane-sealed Si3N4 window-based miniature cell. We report the details on how a commercial Si3N4 window is modified before assembling a graphene membrane, how single-layer graphene membranes are transferred from their metal supports to the modified Si3N4 window, how a modified Si3N4 window covered with a double-layer graphene membrane is assembled onto a blank cell cap, how a nanoparticle catalyst is introduced to the cell cap and then the cell cap is installed onto a cell body to form a complete reaction cell, and how a complete cell is interfaced with a high vacuum chamber of an XPS system before an XPS study of 1.0 wt. %Ni/TiO2 catalyst surface in a flowing mixture for 0.2bar CO and 0.8bar O2 is performed. How the characterization of a catalyst using this type of graphene membrane-sealed Si3N4 window-based miniature cell is relevant to the finding of the actual surface chemistry of a catalyst during catalysis is discussed.

Histopathological and statistical study of corneal repair in rabbits. A new way to understand corneal recovery.

The study aims to evaluate corneal healing post amniotic membrane transplantation in controlled corneal defects, justifying its application in routine ophthalmology practice. The objective is to establish a reliable method for assessing the repair process. In three groups of six adult New Zealand rabbits, keratectomy and a monolayer transplant of dehydrated human amniotic membrane (AM) were conducted in the left eye (OS) with the right eye (OD) serving as the control eye. Clinical signs were assessed, and both eyes were enucleated at 1, 2, and 4 weeks for optical coherence tomography (OCT) measurements and histological analysis, collecting data from different epithelium, stroma, and limbus regions. This study was conducted using a formula that combines histologic data categorizing their presence and/or type as beneficial for corneal repair. No statistically significant differences were found between the experimental and control eyes regarding all clinical signs and OCT measurements. However, a linear model using histopathological results showed a period-implant mode interaction with statistical significance (p=0.010). The use of the single-layer amniotic membrane resulted in improved corneal recovery with the stromal side showing better performance in the first week and the epithelial side proving to be more effective than the stromal side in the long term. For the first time, a statistical formula employing histopathological data is introduced to determine corneal recovery, potentially offering a more accurate and reliable method compared with the observation of clinical signs and corneal measurements with OCT.

Ultra-Strong Janus Covalent Organic Framework Membrane with Smart Response to Organic Vapor.

Vapor-driven smart Janus materials have made significant advancements in intelligent monitoring, control, and interaction, etc. Nevertheless, the development of ultrafast response single-layer Janus membrane, along with a deep exploration of the smart response mechanisms, remains a long-term endeavor. Here, the successful synthesis of a high-crystallinity single-layer Covalent organic framework (COF) Janus membrane is reported by morphology control. This kind of membrane displays superior mechanical properties and specific surface area, along with excellent responsiveness to CH2Cl2 vapor. The analysis of the underlying mechanisms reveals that the vapor-induced breathing effect of the COF and the stress mismatch of the Janus structure play a crucial role in its smart deformation performance. It is believed that this COF Janus membrane holds promise for complex tasks in various fields.

Gamma-irradiated janus electrospun nanofiber membranes for desalination and nuclear wastewater treatment

This study presents the fabrication of double-layer electrospun nanofibrous membranes (DL-ENMs) using polyvinylidene fluoride (PVDF) and polyether sulfone (PES) based polymers with different degrees of hydrophilicity (PES, sulfonated PES, and PES with hydroxyl terminals). A comparative analysis was carried out with single-layer electrospun nanofiber membranes (SL-ENM) with a total thickness of about 375 μm. Using feed solutions, including sodium chloride, sodium nitrate, and simulated nuclear wastewater (SNWW), the performance of DL-ENMs was evaluated for desalination and radionuclide decontamination by direct contact membrane distillation (DCMD) and air gap membrane distillation (AGMD) techniques. The results showed that DL-ENMs, especially those incorporating a sulfonated PES-based hydrophilic layer, exhibited superior permeate fluxes, reaching values of 72.72 kg/m2.h and 73.27 kg/m2.h in the DCMD using aqueous feed solutions of NaCl and NaNO3, respectively, and 70.80 kg/m2.h and 41.96 kg/m2.h using aqueous feed solutions of SNWW in DCMD and AGMD, respectively. Both SL-ENMs and DL-ENMs exhibited high rejection efficiencies and decontamination factors for the feed solutions (>99.9%). In addition, the prepared ENMs were exposed to gamma radiation to evaluate their applicability in real-life applications. The result of irradiation revealed the negative impact of gamma radiation on the fluorine content of PVDF which could be a critical point in using PVDF as a hydrophobic material for decontaminating nuclear wastewater by membrane distillation.

Ultra-flexible TiO2/SiO2 nanofiber membranes with layered structure for thermal insulation

High-performance thermally insulating ceramic materials with excellent mechanical and thermal insulation properties are essential for thermal management in extreme environments. In this work, SiO2 was introduced into the crystalline lattice and grain boundary of TiO2 to inhibit its phase transition and grain growth. Meanwhile, layered TiO2/SiO2 nanofiber membranes (TS NFMs) were designed and prepared. The TS NFMs had lightweight (44 mg/cm3), high tensile strength (4.55 MPa), ultra-flexibility, and low thermal conductivity (31.5 mW∙m−1·K−1). The prepared TS-1100 NFMs had excellent buckling fatigue resistance, which could undergo 100 buckling-recovery cycles at up to 80% strain. Low density and high diffuse reflectance endow the TS NFMs with excellent thermal insulation effects. A single-layer nanofiber membrane was composed of multiple layers of nanofibers. According to the principle of multi-level reflection, the multilayer structure had a better near-infrared reflection effect. Through the stacking effect of layers, a 10 mm thick sample composed of about 300 layers of nanofiber membranes could reduce the hot surface temperature from 1,200 °C to about 220 °C, demonstrating an excellent comprehensive thermal insulation effect. The layered TS NFMs with ultra-flexibility, high tensile strength and high-temperature resistance (1,100 °C) provide a dominant pathway in producing materials in extremely high-temperature environments.

Designing and experimental validation of single-layer mixed foil resonator acoustic membrane to enhance sound transmission loss (STL) within low to medium frequency range

This study presents a novel design for an acoustic membrane structure that employs a parallel-arrangement of mixed foil sound resonators to improve sound absorption and insulation capabilities in the low to medium frequency range. The structure is composed of a single layer of parallel-arranged mixed foil wedge-shaped coffers and a bottom flat panel separated by an air cavity. The mixed thickness-based foil resonators are treated as a combination of independent resonators with unique resonance frequency, resulting in improved sound insulation with broadband efficacy. A comprehensive parametric analysis was carried out using the Finite Element Method (FEM) based COMSOL Multiphysics, yielding the anticipated outcomes. The study revealed that the broadband Sound Transmission Loss (STL) can be tailored by varying the thickness of the top and side walls, the bottom plate thickness, and the depth of the rear air cavity. The findings suggest that existing acoustic membrane design can be highly efficient, achieving, and average STL of over 40 dB ∼ 45 dB across the low to medium frequency range of 500 Hz to 3000 Hz. The experimental validation was conducted in an anechoic chamber, and the results were found to be in close agreement with the FEM simulation results. In comparison to conventional uniform foil sound resonator based acoustic membrane structure, this mixed single-layer square wedge-shaped foil resonator based acoustic membrane exhibits outstanding sound insulation performances in the low to medium frequency range, owing to its lightweight structure and availability of conventional manufacturing techniques. This advanced version of the foil sound resonator based acoustic membrane holds immense promise for the use in acoustics and noise control applications across domestic, commercial, and industrial environments.

Placement optimization of elastic spacers for multi-layer space membrane structure

In recent years, there has been a growing interest in the dynamics of space membrane structures. However, existing research primarily focuses on single-layer membrane structures, leaving a significant research gap in the study of multi-layer structures with elastic spacers. To address this gap, this paper studies the dynamics and interlayer spacing accuracy of multi-layer membrane structures with elastic spacers. Specifically, the research focuses on the placement optimization of elastic spacers. A novel optimization criterion for the elastic spacers has been proposed, and the Particle Swarm Optimizer (PSO) algorithm has been utilized to calculate the optimal spacers positions. Results show that optimally placed elastic spacers can eliminate the crossing modes and improve the interlayer spacing accuracy during vibration.

The biomechanical effects of different membrane layer structures and material constitutive modeling on patient-specific cerebral aneurysms.

The prevention, control and treatment of cerebral aneurysm (CA) has become a common concern of human society, and by simulating the biomechanical environment of CA using finite element analysis (FEA), the risk of aneurysm rupture can be predicted and evaluated. The target models of the current study are mainly idealized single-layer linear elastic cerebral aneurysm models, which do not take into account the effects of the vessel wall structure, material constitution, and structure of the real CA model on the mechanical parameters. This study proposes a reconstruction method for patient-specific trilaminar CA structural modeling. Using two-way fluid-structure interaction (FSI), we comparatively analyzed the effects of the differences between linear and hyperelastic materials and three-layer and single-layer membrane structures on various hemodynamic parameters of the CA model. It was found that the numerical effects of the different CA membrane structures and material constitution on the stresses and wall deformations were obvious, but does not affect the change in its distribution pattern and had little effect on the blood flow patterns. For the same material constitution, the stress of the three-layer membrane structure were more than 10.1% larger than that of the single-layer membrane structure. For the same membrane structure, the stress of the hyperelastic material were more than 5.4% larger than that of the linear elastic material, and the displacement of the hyperelastic material is smaller than that of the linear elastic material by about 20%. And the maximum value of stress occurred in the media, and the maximum displacement occurred in the intima. In addition, the upper region of the tumor is the maximum rupture risk region for CA, and the neck of the tumor and the bifurcation of the artery are also the sub-rupture risk regions to focus on. This study can provide data support for the selection of model materials for CA simulation and analysis, as well as a theoretical basis for clinical studies and subsequent research methods.

Facile fabrication of dual-conductivity, humidity-responsive single-layer membranes: towards advanced applications in sensing, actuation, and energy generation

Facile fabrication of dual-conductivity, humidity-responsive single-layer membranes: towards advanced applications in sensing, actuation, and energy generation

Amniotic Membrane Transplantation-A Surgical Alternative in Peripheral Ulcerative Keratitis

Introduction: Peripheral ulcerative keratitis (PUK) is a group of inflammatory corneal ulcers with stromal thinning and peripheral localization. It begins with immune cellular infiltrates in the juxtalimbal cornea, followed by a crescent-shaped ulcer that appears parallel to the limbus. Medical management includes intense lubrication, antibiotics, along with topical and systemic steroids and immunosuppressants. Definitive surgical management is lamellar patch or penetrating corneal graft. Amniotic membrane has wide array of biological properties, including anti-inflammatory, anti-bacterial, anti-angiogenic, antifibrotic, healing properties hence can be used as an alternative to keratoplasty. Material and Methods: This mono institutional observational retrospective study was conducted on 15 eyes of 15 patients having PUK in a tertiary health care centre. Patients underwent single-layered amniotic membrane transplantation (AMT) in case of corneal thinning involving <1/2 corneal stroma, multi-layered or rolled AMT in cases of corneal thinning involving >1/2 corneal stroma or with moderate to large perforations along with systemic steroids and immunosuppression. Results: All 15 Patients (100%) initially had symptomatic relief,2 patients (13.33%) underwent repeat AMT (86%success rate), 2 failures were noted, out of which 1 patient (6.67%) underwent corneal patch graft while 1 patient (6.67%) underwent large penetrating keratoplasty which failed and landed in Phthisis. Conclusion: AMT is a safe and effective alternative for the surgical management of PUK in combination with local and systemic immunosuppressive therapy. A close collaboration between the ophthalmologist and the physician is mandatory to prevent corneal perforation and decrease patient morbidity and risk of mortality

Improved Energy Harvesting Ability of Single-Layer Binary Fiber Nanocomposite Membrane for Multifunctional Wearable Hybrid Piezoelectric and Triboelectric Nanogenerator and Self-Powered Sensors.

While wearable self-powered electronic devices have shown promising improvements, substantial challenges persist in enhancing their electrical output and structural performance. In this work, a working mechanism involving simultaneous piezoelectric and triboelectric conversion within a monolayer-structured membrane is proposed. Single-layer binary fiber nanocomposite membranes (SBFNMs) (PVDF/CNTX@PAN/CNTX, DPCPCX) with two distinct interpenetrating nanocomposite fibers were created through co-electrospinning, incorporating multiwalled carbon nanotubes (CNTs) into polyvinylidene fluoride (PVDF) and polyacrylonitrile (PAN), respectively. The resulting membrane demonstrated an exceptional synergistic effect of piezoelectricity and triboelectricity along with a high machine-to-electric conversion capability. The addition of CNTs increased the PVDF β-phase and the PAN planar zigzag conformation. As a result, the DPCPC0.5-SBFNMs-based piezoelectric nanogenerator exhibited excellent electrical output (187 V, 8.0 μA, and 1.52 W m-2), maintaining an exceptionally high level of output voltage compared with other piezoelectric nanogenerators. It successfully illuminated 50 commercial light-emitting diodes simultaneously. The output voltage of DPCPC0.5-SBFNMs was 5.1 and 4.6 times higher than that of PAN or PVDF single-fiber membranes, respectively. Furthermore, the peak voltage of DPCPC0.5-SBFNMs exceeded that of co-electrospinning PVDF/CNT1.0@PAN (DPCP1.0) and PVDF@PAN/CNT1.0 (DPPC1.0) by 20 and 10 V, respectively. The piezoelectric sensor made of DPCPC0.5-SBFNMs accurately sensed human movement, ranging from tiny to large, and demonstrated utility as an alarm in medical treatment, fire fighting, and monitoring. Endogenous triboelectricity is proposed in SBFNM piezoelectric materials, enhancing electromechanical conversion and electrical output capacity, thereby promising a wide application potential in self-powered wearable electronic devices.

Dual liquid-assisted single-layered Janus mesh membrane with controllable and efficient directional water transport for multiple applications

Janus porous membranes with anisotropic interfaces exhibiting directional liquid transport properties have emerged as important tools for addressing real-world issues, such as oil-spill cleanup and fog collection. Here, a single-layered Janus mesh membrane with asymmetric wettability and a well-tuned hydrophilization depth is prepared using an ethanol-assisted floating method. Consequently, the well-regulated hydrophilization depth combined with a water-assisted strategy achieves controllable and efficient directional water transport properties, which also gives rise to a high anisotropic critical breakthrough pressure. In addition, the water-assisted controllability can form an on–off gate capable of allowing or blocking water to pass through upon request. Moreover, we theoretically and experimentally determine the changeable contact area as important in directional water transport properties. Controllable directional water transport behavior with a high pressure difference has been demonstrated in on-demand oil–water separation and intravenous infusion, whereas the efficient directional water transport properties have potential applications in fog collection. Overall, this work provides a new idea for the preparation of a single-layered multifunctional Janus mesh membrane with a high anisotropic critical breakthrough pressure and opens an avenue for controllable and efficient directional water transport properties for diverse applications.

Scaling of ionic conductance in a fluctuating single-layer nanoporous membrane

Single-layer membranes have emerged as promising candidates for applications requiring high transport rates due to their low resistance to molecular transport. Owing to their atomically thin structure, these membranes experience significant microscopic fluctuations, emphasizing the need to explore their impact on ion transport processes. In this study, we investigate the effects of membrane fluctuations on the elementary scaling behavior of ion conductance G as a function of ion concentration c_{0}, represented as G = beta c_{0}^{alpha }, using molecular dynamics simulations. Our findings reveal that membrane fluctuations not only alter the conductance coefficient beta but also the power-law exponent alpha. We identify two distinct frequency regimes of membrane fluctuations, GHz-scale and THz-scale fluctuations, and examine their roles in conductance scaling. Furthermore, we demonstrate that the alteration of conductance scaling arises from the non-linearity between ion conductance and membrane shape. This work provides a fundamental understanding of ion transport in fluctuating membranes.

Fabrication and characterization of hydrophobic/hydrophilic dual-layer polyphenyl sulfone Janus membrane for application in direct contact membrane distillation

In this study, single-layer (SL) and dual-layer (DL) polyphenyl sulfone (PPSU) flat sheet nanocomposite Janus membranes were fabricated via a combination of VIPS and NIPS techniques for direct contact membrane distillation (DCMD) for the first time. Hydrophobic silica nanoparticles (SiNP-B) were incorporated into the SL membranes and the top layer of the DL membranes, while hydrophilic silica nanoparticles (SiNP-L) were added into the down layer of the DL membranes. The effect of the SiNP-B concentration (1–5 wt%) and the top layer thickness (50 and 100 μm) on the morphology, mean pore size (MPS), thickness, porosity, surface roughness, water contact angle (WCA), liquid entry pressure, mechanical strength, and thermal conductivity were investigated. All of the membranes showed a finger-like structure surrounded by a sponge-like structure. The membranes were examined in the DCMD of a 35,000 ppm saline solution at different feed temperatures (50–70 °C) and flow rates (250–1000 mL/min). The DL membranes possessed higher fluxes than the SL membranes through increasing MPS and WCA. The DL membrane with a SiNP-B concentration of 2 wt% and a hydrophobic thickness of 50 μm (DL- 2,50) achieved the highest flux (42.68 ± 0.35 kg/m2h) and salt rejection (94.90 %) during 5 h. This membrane has an MPS of 0.22 ± 0.03 μm, a thickness of 201 ± 4 μm, and a porosity of 76 ± 2 %. It could be concluded the proper pore size distribution is the most important factor in achieving a successful DCMD operation.

Counterion Transference Numbers in the Cell Model of a Charged Membrane

The paper suggests exact formulae for calculating the electromigration, diffusion and convective numbers of counterion transport in the cell model of a charged membrane depending on the physicochemical parameters and the equilibrium concentration of the electrolyte. The cell model was previously developed to calculate all the kinetic coefficients of the Onsager matrix and the asymmetry of the cross coefficients was established. The limiting case of an ideally selective membrane is studied in detail, for which approximate formulae for transference numbers are obtained. The obtained dependences are illustrated by graphs using the example of the MK-40 cation-exchange membrane after conditioning at room temperature. The proposed method for calculating the transference numbers is applicable to any single-layer membranes in binary electrolyte solutions.

Highly efficient B(OH)3 removal by single-layered graphene membrane with embedded crown nanopores

Trace boron in seawater, usually presented as boric acid (B(OH)3), should be firstly transformed into ionic state, in desalination plants, which represents high energy consumption and high cost. Therefore, direct removal of B(OH)3 is significant and energy-efficient for industrial boron removal, which is still a great challenge. A very recent work [Desalination, 533 (2022) 115755] provides strong theoretical guidance on making efficient boron removal devices utilizing 2D materials with hydrophilic pores. However, limited effort has devoted to explore other 2D porous membrane aiming at further improving the performance of boron acid removal. Herein, using molecular dynamics (MD) simulation, we investigated the effect of single-layered graphene nanosheet embedded with hydrophilic crown nanopores on the direct removal of boric acid. We construct six typical graphene crown pores with varied pore dimensions. Our MD results demonstrate that the utilized graphene crown pores show high water permeability, simultaneously accompanied by an outstanding B(OH)3 rejection (mostly over 90%). The water permeabilities through the crown pores achieve a highest value of 6.01 L cm−2 day−1 MPa−1. Remarkably, the water fluxes in each pore are evaluated to be 2.15 ∼ 20.1 × 1013 per day per MPa per pore, featuring 1–2 orders of magnitude improvement compared with the previous best report of 2-dimensional nanopores, with the comparable B(OH)3 rejection. Free energy calculations indicate that a water molecule is energetically more favorable to transport through graphene crown nanopore than B(OH)3. Our findings highlight that a porous graphene embedded with hydrophilic crown nanopores can be not only used for efficaciously removing B(OH)3 but also enable the fast water flow, which is desirable in desalination plants.