One-step Interfacial Polymerization Research Articles

A novel clover-like COFs membrane fabricated via one-step interfacial polymerization for dye/salt separation

Covalent organic frameworks (COFs) membranes have exhibited great applications in wastewater treatment due to their highly ordered porous architecture. Currently, numerous studies have focused on the hexagonal-structured COFs synthesized with linear C2 and C3 precursor. However, the C2 monomer is limited-variety and high-cost. Herein, a novel clover-like structure COFs membrane is successfully fabricated for the first time. Meta-position monomer m-phenylenediamine (MPD) and 1,3,5-triformylbenzene (TFB) are used to synthesize the clover-like COFs membrane by interfacial polymerization (IP) method on the nylon substrate directly. The optimized MPD-TFB/Nylon membrane shows excellent water permeance of 94.4 L m−2 h−1 bar−1, which is higher than hexagonal-structured COFs membrane, in Congo red (CR) and NaCl mixed solution The rejections are 98.6% for CR and 2.9% for NaCl. This work opens a novel route for designing the COFs membrane with clover-like channels, manifesting the usage of linear C2 monomers is unnecessary. Besides, it has been found that the unique clover-like structure can improve the water molecular transport path under the same dye molecules deposition situation compared with hexagonal structure COFs membrane.

A Novel Clover-Like Cofs Membrane Fabricated Via One-Step Interfacial Polymerization for Dye/Salt Separation

A Novel Clover-Like Cofs Membrane Fabricated Via One-Step Interfacial Polymerization for Dye/Salt Separation

Low-pressure highly permeable polyester loose nanofiltration membranes tailored by natural carbohydrates for effective dye/salt fractionation

With the continuous pressure of water contamination caused by textile industry, loose nanofiltration (LNF) membranes prepared by green materials with an extraordinary water permeability are highly desirable for the recovery and purification of dyes and salts. In this work, low-pressure LNF membranes with ultrahigh permeability were fabricated via one-step interfacial polymerization (IP), in which inexpensive natural carbohydrate-derived sugars with large size and low reactivity were utilized as aqueous monomers to design selective layer. A systematic characterization by chemical analysis and optical microscopy demonstrated that the formed polyester film features not only loosen the structure, but also results in a hydrophilic and negatively charged surface. The optimized sucrose-based membrane (Su0.6/TMC0.1) with an excellent water permeability of 52.4 LMH bar−1 was found to have a high rejection of dyes and a high transmission of salts. In addition, the sugar-based membrane manifested an excellent anti-fouling performance and long-term stability. Furthermore, the non-optimized Gl0.6/TMC0.1 and Ra0.6/TMC0.1 membranes also shown a high water permeability, while maintaining a competitive dye/salt separation performance, which confirmed the universal applicability of the membrane design principle. Therefore, the proposed new strategy for preparing next-generation LNF membranes can contribute towards the textile wastewater treatment.

Carbon quantum dots doped thin-film nanocomposite (TFN) membrane on macroporous ceramic hollow fiber support via one-step interfacial polymerization

The amino (NH2) modified carbon quantum dots (N-CDs) doped thin film nanocomposite (TFN) membranes were prepared on the macroporous ceramic hollow fiber (CHF) substrate with a pore size of about 300 nm through one-step interfacial polymerization (IP) process. The abundant hydroxyl, carboxyl, and amino groups of aqueous phase additives (N-CDs and polyvinyl alcohol (PVA)) provide attachment sites for ethylenediamine (EDA) to build a modified membrane structure. Molecular dynamics (MD) simulation was employed to study the diffusion process in IP. The results show that the addition of N-CDs reduced the EDA diffusion coefficient significantly from (4.58 ± 0.50) × 10−5 cm2/s to (1.44 ± 0.10) × 10−5 cm2/s. The wrinkled and ultra-thin polyamide (PA) layer with a thickness of 28 ± 3 nm was observed by the field-emission scanning electron microscopy (SEM). X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), and dynamic contact angle were used to characterize the chemical structure and hydrophilicity. The effect of additives concentration on pervaporation (PV) performance for ethanol (EtOH) dehydration has been investigated systematically. The resultant membrane exhibited excellent performance with the total permeation flux of 3.15 kg·m−2·h−1 and separation factor of 1127. Besides, there was no significant performance decline during the 160 h long-term stability test, indicating that the membranes own the potential application in industry.

Synthesis and properties of multifunctional microencapsulated phase change material for intelligent textiles

Microencapsulated phase change materials (MEPCMs) have been widely used in many fields as thermal energy storage materials. This study reported a novel MEPCM with the functions of thermal energy storage, photothermal conversion, ultraviolet (UV) shielding, and superhydrophobicity, which was particularly suitable for intelligent textiles. The microcapsules based on an n-eicosane core and a CuO-doped polyurea shell with hierarchical structure were fabricated through a one-step interfacial polymerization. The morphology of the capsules and the hierarchical shell structure were identified through scanning and transmission electron microscopy. Thermal analysis indicated that the microcapsules had a high latent heat of 162.3 J/g and demonstrated a high thermal reliability. These microcapsules achieved a good photothermal conversion capability and can reduce UV radiation by approximately 30%. The water contact angle of the MEPCM was over 148° and showed a good superhydrophobic property. Cotton fabric coated with the prepared MEPCM was investigated. Results showed that it achieved a high phase change enthalpy of 36.8 J/g, an effective thermoregulation capability, and a large contact angle of 141.6°.

Impedance variation with different relative humidities of PAni/Mn nanofibres

This paper presents the humidity sensing properties of surface-modified polyaniline (PAni). In this study, the impedance response and dielectric properties of pure- and doped-PAni have been investigated as a function of relative humidity (RH%) and frequency. PAni and PAni/Mn composite samples are synthesized by one-step interfacial polymerization process. The structural properties and surface morphologies of the prepared materials have been characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM), respectively. XRD confirms the formation of PAni and it shows semi-crystalline behaviour. FESEM shows granular, porous and well-distributed structure. It has been observed that the porosity and nanogranular structure increased with increasing doping percentage. Here, we observe that porous and granular structure of Mn-doped PAni shows better response and recovery time ($${\sim }28\hbox { s}$$) and decreases in electrical impedance. Dielectric constants, dielectric loss and AC conductivity have also been discussed with variations in frequency and relative humidity.

The establishment of high-performance anti-fouling nanofiltration membranes via cooperation of annular supramolecular Cucurbit[6]uril and dendritic polyamidoamine

In this work, annular supramolecular cucurbit[6]uril (CB6) and dendritic polyamidoamine (PAMAM) were employed to construct high-performance nanofiltration (NF) membranes via one-step interfacial polymerization (IP) process. The obtained membrane features not only the enlarged polyamide tunnels based on the large steric hindrance of CB6 and PAMAM but also the novel hydrophobic rotaxane tunnels based on the host-guest chemistry between CB6 and piperazine (PIP) or PAMAM. The CB6/PAMAM-modified membrane achieved nearly four times enhancement of pure water permeability (PWP) compared to the unmodified traditional membranes with still high Na2SO4 rejection. This indicates the positive contribution of CB6/PAMAM-modification to overcome the “trade-off” effect limiting NF development. In addition, the modified membrane shows the industry-leading separation performance for monovalent and bivalent anions due to the cooperation between the modified pore-size and surface charge. More valuably, CB6/PAMAM-modified membrane manifests the strong anti-fouling property not only in inorganic salt system but also in organic pollutant system based on the modified surface characteristics, indicating its broader application fields. This provides a feasible method to prepare a high-performance anti-fouling NF membrane.

Preparation of isocyanate microcapsules as functional crosslinking agent by minimalist interfacial polymerization

Isocyanate is an extremely high activity compound that has been extensively used in the chemical materials. In this study, we employ microcapsules in preserving the activity of isocyanates and controlling their release in wood adhesives for plywood. Isocyanate microcapsules were synthesized by a one-step interfacial polymerization in an oil-in-water (O/W) emulsion. The particle size distribution, chemical structure, morphology, activity and stability of the obtained isocyanate microcapsules were characterized by laser particle size analyzer, n-dibutylamine titration, FTIR, SEM, and a universal strength testing machine. The as-synthesized microcapsules had approximately 25% active –NCO group and the core accounted for 77% of the total weight. The isocyanate microcapsules demonstrated satisfactory stability by preserving majority of the active –NCO group and core weight during 180 days of storage. These isocyanate microcapsules were used as functional crosslinking agent for making plywood. The resultant plywood showed higher tensile shear strength than the strength mandated in the Chinese National Standard (GB/T 9846-2015). Furthermore, the wet strength was greatly improved to meet the Class I and II plywood standards. Additionally, the stability of isocyanate microcapsules in wood adhesives were significantly enhanced for a prolonged application time. Their excellent bonding properties and stability make isocyanate microcapsules an ideal additive for use in chemical and manufacturing materials.

Nano-encapsulated phase change materials prepared by one-step interfacial polymerization for thermal energy storage

A simple one-step interfacial polymerization method without special requirements for fabrication of paraffin@ polymethyl methacrylate (PCM@PMMA) nanocapsules is developed. Moreover, all the raw materials are cheap, innocuous and rich in resource. The influences of the mass ratio of methyl methacrylate/Paraffin (MMA/PCM) and stirring speed are studied. Scanning electron microscope (SEM), Fourier transformed infrared spectroscopy (FT-IR), Differential scanning calorimetric (DSC) and Thermo gravimetric analysis (TGA) are employed to characterize the as-prepared PCM@PMMA nanocapsules. Nano-encapsulated PCM could be successfully obtained under the stirring speed of 800 rpm for 2.5 h. The surface of the spherical nano-encapsulated PCMs is homogeneous, smooth and compact, and the particle size is in the range of 200–400 nm. The nano-encapsulated PCM are stable and reliable with the melting enthalpy of about 64.93 J/g and crystallization enthalpy of about 66.45 J/g. TGA results indicate that the nano-encapsulated PCM degraded in three steps and have good thermal stability with the content of the PCM about 52.95%. The PCM@PMMA nanocapsules could be promising for thermal energy storage application.

Facile fabrication of highly ordered polyaniline–exfoliated graphite composite for enhanced charge storage

A facile method was developed for the fabrication of electrochemically exfoliated graphite (EG) intercalated with polyaniline (PANI) via one-step interfacial polymerization at room temperature to produce a conductive EG-PANI composite. The grafting of PANI nanoparticles on the EG surface was confirmed by microscopy and analytical tests. The EG-PANI exhibited higher areal capacitance (CA) and better electrochemical performance than either EG or PANI. A solid-state asymmetrical supercapacitor (SASc) device was fabricated to evaluate the energy-storage potential of EG-PANI using EG as negative electrode and EG-PANI as positive electrode. The SASc device exhibited high CA (80.4 ± 2.3 mF/cm2) at current density of 1 mA/cm2 and excellent capacitance retention (90.2%) after 1000 galvanostatic charge–discharge cycles at 5 mA/cm2. The specific power and energy density were as high as 4.14 mW/cm2 at current density of 5 mA/cm2 and 9.07 μWh/cm2 at current density of 1 mA/cm2, respectively. After charging just for 10 s at 3.5 V, the output of two SASc devices connected in series illuminated different forward-voltage LEDs for over 5 min without diminished brightness. This work represents a new direction for developing EG intercalated PANI to enhance capacitive efficiency of graphite materials for fabrication of supercapacitors.

A monolithic hydro/organo macro copolymer actuator synthesized via interfacial copolymerization

Synthetic polymer actuators have attracted increasing attention for their potential applications in artificial muscles, soft robotics and sensors. The majority of previous efforts have focused on smart hydrogels with bilayer structures that can change their shape in response to environmental stimuli, such as temperature, light and certain chemicals. However, the practical application of hydrogels is limited because of their low modulus and weak mechanical strength. Here we synthesized a robust monolithic actuator of a macro-scale hydro/organo binary cooperative Janus copolymer film. The process involves direct, one-step interfacial polymerization of immiscible hydrophilic and hydrophobic vinyl monomer solutions, and the resultant product exhibited binary cooperative shape transformation to multiple external stimuli. The Janus copolymer film can work in both aqueous solutions and organic solvents, with bidirectional and site-specific bending arising from cooperative asymmetric swelling/shrinking of the hydrogel and organogel networks. In addition, the as-prepared Janus copolymer film can act as a sensor element for solvent leakage detection. This binary cooperative strategy is applicable to most immiscible monomer systems and provides a general approach to developing novel functional copolymer materials.

Fabrication and characterization of a novel poly(amide-urethane@imide) TFC reverse osmosis membrane with chlorine-tolerant property

A novel poly(amide-urethane@imide) reverse osmosis (RO) composite membrane with chlorine-tolerant property was prepared on a polysulfone supporting film through two-step interfacial polymerization. The crosslinking agent – 5-choroformyloxyisophaloyl chloride (CFIC) was first reacted with 4-methyl-phenylenediamine (MMPD) via interfacial polymerization to get the nascent poly(amide-urethane) base membrane (CFIC–MMPD) without curing treatment. Then the resultant base membrane contacted again with the second aqueous solution containing functional secondary amine – N,N′-dimethyl-m-phenylenediamine (DMMPD) to obtain the poly(amide-urethane@imide) TFC RO membrane (MMPD–CFIC@CFIC–DMMPD). X-ray photoelectronic spectroscopy (XPS) was combined with attenuated total reflectance infrared (ATR-IR) to verify that the ultrathin polyimide film (CFIC–DMMPD) has been successfully grafted on the surface of the MMPD–CFIC base membrane. The images of scanning electronic microscopy (SEM) and atomic force microscope (AFM) showed that the poly(amide-urethane@imide) membrane has much smoother, more hydrophilic surface than the poly(amide/imide-urethane) membrane (MMPD/DMMPD–CFIC) prepared by conventional one-step interfacial polymerization of CFIC and composite MMPD/DMMPD. However, the permeation experiment revealed that the poly(amide-urethane@imide) membrane has a slight loss in both salt rejection and water flux than the poly(amide/imide-urethane) membrane and conventional commercialized polyamide membrane (MPD–TMC), but exhibits better chlorine-tolerant property due to the introduction of ultrathin polyimide film (CFIC–DMMPD) on the outmost surface of the TFC RO membrane, and the combination of IR and XPS analyses shows a good agreement with the chlorine exposure results of membranes.

Controllable synthesis of MnO2/polyaniline nanocomposite and its electrochemical capacitive property.

Polyaniline (PANI) and MnO2/PANI composites are simply fabricated by one-step interfacial polymerization. The morphologies and components of MnO2/PANI composites are modulated by changing the pH of the solution. Formation procedure and capacitive property of the products are investigated by XRD, FTIR, TEM, and electrochemical techniques. We demonstrate that MnO2 as an intermedia material plays a key role in the formation of sample structures. The MnO2/PANI composites exhibit good cycling stability as well as a high capacitance close to 207 F g−1. Samples fabricated with the facile one-step method are also expected to be adopted in other field such as catalysis, lithium ion battery, and biosensor.

One-step fabrication of high selective hollow fiber nanofiltration membrane module

A novel hollow fiber composite Nanofiltration (NF) membrane was fabricated by an improved preparation procedure. Using hollow fiber ultrafiltration (UF) membrane modules as the supporting modules, hollow fiber composite NF modules were fabricated by the one-step interfacial polymerization method. The effects of preparation conditions (such as concentration of the monomers, reaction time of monomers and ambient relative humidity, etc.) on the performance of the hollow fiber composite membranes were studied. When tested at 0.6 MPa, room temperature, the hollow fiber composite membrane had a rejection sequence of MgSO4>Na2SO4>MgCl2>NaCl and a permeate flux sequence of NaCl>Na2SO4> MgSO4>MgCl2. The nagative charge character of the membrane surface was examined by streaming potential methods. The effect of the surface electrolyte properties on the membrane separation performance was investigated. The morphologies of the hollow fiber composite Nanofiltration membranes were studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM).