Interfacial Polycondensation Research Articles

Novel polyesters based on indazole moiety: Synthesis, characterization and applicability as efficient inhibitors for acidic X-65-steel corrosion

In this report, novel series of unsaturated polyesters Va­d and VIa­d containing indazole moiety were successfully prepared via interfacial polycondensation technique of indazole derivatives III and IV with different aromatic and aliphatic acid chlorides; isophthaloyl­, terephthaloyl­, adipoyl­, and sebacoyl chlorides. The prepared polyesters were categorized by elemental analyses, IR, 1H NMR, Mass spectra, GPC, Thermogravimetric (TGA), X-ray analyses (XRD), and therefore the morphology was examined by scanning microscopy (SEM). They showed high thermal stability and different morphology structure. The corrosion protection performance of prepared polyesters Va­d and VIa­d on X65­steel in molar oil of vitriol was assessed using potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), and SEM. Electrochemical tests (EIS and PDP) displayed polymers could efficiently impede the X65­steel corrosion and acted as inhibitors of the mixed type. At the optimal dose of 150 mg/L, the protection capacities of Va-d and VIa-d polymers ranged from 86.9% to 97.8%. adsorption of Va­d and VIa­d followed the adsorption model of Langmuir isotherm. Surface morphology examination by SEM also revealed that Va­d and VIa­d polymers form an efficient block layer on the surface of X65­steel to separate the acidic solution.

Surface construction of Ni(OH)2 nanoflowers on phase-change microcapsules for enhancement of heat transfer and thermal response

A phase-change microcapsule system based on an n-docosane core and SiO2/nanostructural Ni(OH)2 layer-by-layer shell was designed with the aim to enhance the heat transfer and thermal response capability of phase-change microcapsules. This system was fabricated through emulsion-templated interfacial polycondensation to form a SiO2/n-docosane microcapsule system, followed by anchoring Ni(OH)2 nanoflowers on the surface of the SiO2 shell via structure-directed interfacial precipitation. The resultant microcapsule system achieved a satisfactory latent heat-storage capacity of around 130 J/g with high energy-storage efficiency over 99%. Compared to conventional SiO2/n-docosane phase-change microcapsules, this microcapsule system not only presents high thermal conductivity, rapid heat transfer rate, good leakage prevention capability, high heat charging-discharging stability, but also exhibits a good phase-change reversibility and resilience ability to perform repetitious solid-liquid phase transformations. The combination of traditional phase-change microcapsules with a nanostructural Ni(OH)2 outer layer results in a significant enhancement in heat transfer, which makes the system a fast thermal response ability to satisfy a variety of applications where fast and stable thermal energy storage/release is required. Through constructing the Ni(OH)2 nanoflowers on the surface of conventional phase-change microcapsules, this study offers a promising strategy for the design and fabrication of high-performance phase-change microcapsules with fast thermal response.

Nanoflaky nickel-hydroxide-decorated phase-change microcapsules as smart electrode materials with thermal self-regulation function for supercapacitor application

A nanoflaky nickel-hydroxide-decorated phase-change microcapsule system [designated as Ni(OH)2-SiO2-MEPCM] was designed as a smart electrode material for supercapacitor application. This system was constructed through microencapsulating n-docosane core into a silica shell via emulsion-templated interfacial polycondensation, followed by fabricating a nanoflaky Ni(OH)2 layer on the surface of silica shell through structure-directed interfacial precipitation. Such a combination of phase-change microcapsules and electrochemically active material makes the Ni(OH)2-SiO2-MEPCM synchronously implement thermal self-regulation and electrochemical energy storage. The Ni(OH)2-SiO2-MEPCM shows a perfect core-shell structured morphology and well-defined nanoflaky surface microstructure. The Ni(OH)2-SiO2-MEPCM not only possesses a good temperature regulation capability with a latent-heat capacity of around 140 J/g but also exhibits an excellent thermal cycle stability and good high-temperature shape stability. Most importantly, compared to traditional electrode materials, the Ni(OH)2-SiO2-MEPCM can perform effective thermal self-regulation to regulate the micro-ambient temperature by its n-docosane core when used as an electrode material for supercapacitors, leading to improved electrochemical performance and good long-term cycle stability with capacitance retention of 86.2% after 3000 charge-discharge cycles at a high ambient temperature of 50 °C. All of these features indicate that the Ni(OH)2-SiO2-MEPCM developed by this work has great potential as a smart electrode material for electrochemical energy-storage applications.

Polyurethane/n-octadecane@silicon dioxide-polyhydroxyethyl methacrylate form-stable phase change materials with enhanced mechanical properties and thermal energy storage

A kind of polyurethane rubber (PU)/n-octadecane (n-OD)@silicon dioxide (SiO2)-polymethyl acrylate (PHEMA) form-stable phase change material (PCM) was fabricated in this paper. n-OD@SiO2-PHEMA microcapsules were prepared in one-pot, through interfacial hydrolysis polycondensation of alkoxy silanes and radical polymerization of HEMA. Then, n-OD@SiO2-PHEMA microcapsules were added into PU matrix to obtain PU/n-OD@SiO2-PHEMA composites. SiO2-PHEMA hybrid shell not only provides a shelter for core material, but also increases interfacial bonding between microcapsules with PU and effectively improves the mechanical properties of composites. The morphologies, chemical compositions and crystal structures of microcapsules and composites were characterized by SEM, TEM, FT-IR and XRD methods. The thermal and mechanical properties of the microcapsules and composites were characterized by differential scanning calorimetry and mechanical performance tests. The results show that the thermal and mechanical properties of PU/n-OD@SiO2-PHEMA composites were better than those of neat PU. The PU/n-OD@SiO2-PHEMA composites endow the microcapsules with improved thermal reliability and leakage proof property. The composites were found as form-stable PCM with low leakage rate. The phase change latent heat of the PU/n-OD@SiO2-PHEMA composites was up to 85.1 J/g and the composites can be used for thermal energy storage.

A thermoresponsive composite separator loaded with paraffin@SiO2 microparticles for safe and stable lithium batteries

Lithium-ion batteries (LIBs)-related accidents have been reported for years and safety issues are stumbling blocks for the practical applications of lithium metal batteries (LMBs) with higher energy density. More effective strategies to shut down the battery at the early stage of thermal runaway with less side effects on the electrochemical performance are greatly desired. In this work, the core–shell structural paraffin@SiO2 microparticles were synthesized by in situ emulsion interfacial hydrolysis and polycondensation and the paraffin@SiO2-loaded separator (PSS) was prepared by a facile filtration method. The introduction of hydrophilic silica shells in paraffin@SiO2 enhanced the wettability of carbonate electrolyte with the composite separator and improved the processability of soft paraffin. As a result, when used in LMBs at room temperature, the cell with PSS inside had a more uniform deposition of lithium, a much lower overpotential and a more stable electrochemical performance than the cell with the blank separator or the conventional pure paraffin-loaded separator inside. More significantly, when a heating stimulation (i.e. 115 ℃) was subjected to the cell with PSS inside, the paraffin in the core of paraffin@SiO2 could be released, blocking the gaps between particles and the pores in the separator and efficiently stopping the transportation of Li+ between two electrodes, resulting in the thermally-induced shutdown of the cell below the melting temperature of PE (~135 ℃) in the Celgard2325 separator. The core–shell structure of paraffin@SiO2 enables the maintaining of each component’s benefits while avoiding each one’s drawbacks by elaborating microstructural design. Therefore, the conventional dilemma between the electrochemcial performance and safety of LMBs could be solved in the future.

Electrochemically assisted polyamide deposition at three-phase junction

A three-phase junction formed between a solid electrode placed between solutions of the organic phase and the aqueous phase is employed for localized and electrochemically assisted nylon-6,6 deposition. The fluorine-doped tin oxide (FTO) conductive support (serving as the working electrode) is immersed into the cell filled with the aqueous solution of 1,6-hexanediamine (1,6-DAH) and the organic solution of adipoyl chloride (AC) dissolved in 1,2-dichloroethane. The interfacial polycondensation reaction between these two reagents occurs spontaneously at the liquid–liquid interface at elevated pH and is inhibited when diamine is fully protonated. With this in mind, we have designed a system where the pH close to the three-phase junction was increased using electrochemical water reduction triggering very localized polyamide deposition.

N-Eicosane-Fe3O4@SiO2@Cu microcapsule phase change material and its improved thermal conductivity and heat transfer performance

This study focused on developing an efficient phase change material (PCM) with a stable shape that can be applied in a wide range of industries. To prevent leakage of the PCM liquid at a temperature above the melting point, we used an encapsulation method by making use of an interfacial polycondensation reaction, and attempted to develop a new PCM with excellent thermal conductivity and thermal energy storage capacity. In order to improve the functionality of the PCM in latent thermal storage applications, a magnetic material, Fe3O4, was mixed with n-eicosane and a shape-stable phase change microcapsule with a silica shell was successfully prepared. In this study, we loaded Cu metal nanoparticles on the outer wall of the capsule with the aim of improving the thermal conductivity of the material for efficient heat transfer. The results indicated that the n-eicosane-Fe3O4@SiO2@Cu microcapsule has excellent heat transfer ability owing to its high thermal conductivity and exhibits efficient thermal energy storage–release performance by suppressing supercooling. The n-eicosane-Fe3O4@SiO2@Cu microcapsule showed an encapsulation efficiency (Een) of 61.48%, an energy storage efficiency (Ees) of 61.47%, and a thermal storage capacity (Ces) of 99.99%. Moreover, the multi-cycle differential scanning calorimetry scan showed excellent thermal reliability and shape stability, even in repetitive melting–cooling processes, suggesting that it is a promising PCM that can be used in industrial applications.

Temperature and pH dual-stimuli-responsive phase-change microcapsules for multipurpose applications in smart drug delivery

Temperature/pH dual-stimuli-responsive phase-change microcapsules (Dual-SR-MEPCM) were designed that can form the basis of smart drug delivery systems. They employed n-eicosane as a phase change material (PCM) microencapsulated in an acrylate-functionalized silica shell via emulsion-templated interfacial polycondensation. A poly(N-isopropylacrylamide-co-acrylate acid) functional layer was then fabricated on the surface of the silica shell through surfactant-assisted radical polymerization. The combination of phase-change microcapsules and stimuli-responsive material results in a system that synchronously implements thermal self-regulation by its PCM core together with controllable drug release through its polymeric functional layer. The resultant Dual-SR-MEPCM exhibits regularly spherical morphology, uniform particle-size distribution and well-defined core–shell microstructure, which indicates successful construction according to our design principle. This system has been further evaluated for multipurpose applications in thermal regulation and drug delivery with independent temperature and pH triggering. The Dual-SR-MEPCM not only shows a high thermal energy-storage capacity of over 160 J/g, but also good anti-leakage performance, thermal cycle stability and high-temperature shape stability. Our studies also reveal independent stimuli-responsive behaviors for temperature and pH when using bovine serum albumin and doxorubicin hydrochloride as model drugs. All of these features indicate that the Dual-SR-MEPCM designed in this study can serve as a promising candidate for smart drug delivery systems, with great potential for future multipurpose applications in advanced pharmaceutical areas.

Interfacial Polymerization: From Chemistry to Functional Materials.

Interfacial polymerization, where a chemical reaction is confined at the liquid-liquid or liquid-air interface, exhibits a strong advantage for the controllable fabrication of films, capsules, and fibers for use as separation membranes and electrode materials. Recent developments in technology and polymer chemistry have brought new vigor to interfacial polymerization. Here, we consider the history of interfacial polymerization in terms of the polymerization types: interfacial polycondensation, interfacial polyaddition, interfacial oxidative polymerization, interfacial polycoordination, interfacial supramolecular polymerization, and some others. The accordingly emerging functional materials are highlighted, as well as the challenges and opportunities brought by new technologies for interfacial polymerization. Interfacial polymerization will no doubt keep on developing and producing a series of fascinating functional materials.

Intrinsic kinetics of interfacial polycondensation reactions– the reaction of mPDA with TMC

The performance of thin film composite membranes used in reverse osmosis is decided by the thickness and structure of the thin functional layer, which in turn depend on the kinetics of the interfacial polycondensation (IP) reaction which produces this layer. Quantitative determination of these kinetics has been a challenge. In the present study, we extend the method of pH-metry developed in our earlier work to the study of IP kinetics, in the presence of the side reaction of hydrolysis of the organic phase monomer. The method has been used to establish the kinetics of MPDA –TMC system in the presence and absence of a surfactant, Tween-85. The experimental method used eliminates all transport resistances, so that intrinsic kinetic control of the observed process is ensured. The hydrolysis reaction is studied separately by an adaptation of the same method, and those kinetics are systematically incorporated in the treatment of the data from the IP reaction. The observed kinetics have been fitted to a lumped kinetic form of the power law type, and show that the reaction is approximately first order in the acid chloride group concentration, and order 1.6 in the amine group concentration. The surfactant has been seen to influence the magnitude of the rate constant significantly. The reaction usually stops well short of 100% conversion of the stoichiometrically limiting monomer, because of the lowering of pH which restricts the availability of the aqueous phase monomer at the reaction locale.

Immobilization of laccase on phase-change microcapsules as self-thermoregulatory enzyme carrier for biocatalytic enhancement

The immobilized enzymes on conventional solid carriers usually have to suffer from progressive deterioration in biocatalytic activity at high temperatures. To address such an annoying problem, we designed a self-thermoregulatory enzyme carrier system based on phase-change microcapsules for immobilization of laccases. A primary phase-change microcapsule system was first fabricated with n-docosane as a phase change material core and silica as an inorganic shell via interfacial polycondensation, and then a polydopamine/gold nanoparticles hybrid layer was coated on the surface of silica shell through surfactant-assisted self-assembly and in-situ reduction of Au ions to form the enzyme carrier. The introduction of n-docosane core endows the enzyme carrier with a thermal self-regulation function through phase transition. A laccase was immobilized onto the surface of this enzyme carrier by using an immobilized copper chelate method. The resultant immobilized laccase exhibits a perfect layer-by-layer core-shell microstructure and a satisfactory latent heat-storage capacity over 120 J/g. By a unique combination of laccase and the self-thermoregulatory enzyme carrier, the resulting immobilized laccase not only achieves a significant improvement in biocatalytic activity at high temperatures due to in-situ thermal management and temperature regulation by its n-docosane core during the biocatalytic process, but also gains an enhancement in thermal and storage stabilities. In addition, the immobilized laccase on the novel enzyme carrier developed by this work demonstrates outstanding performance in operation reliability, phase-change reversibility, thermal and shape stabilities, reusability, and tolerance to various metal ions and organic solvent for practical biocatalytic applications along with effective thermal self-regulation. This study offers an innovative strategy for design and development of immobilized enzymes with an enhanced enzyme activity for biocatalytic applications in a wider temperature region.

Synthesis and Permselectivity of a Soluble Two-Dimensional Macromolecular Sheet by Solid–Solid Interfacial Polycondensation Followed by Chemical Exfoliation

Two-dimensional (2D) network polymers with nano-sized pores are generally insoluble, and therefore, it is difficult to determine their molecular structures and to fabricate their membranes. Soluble 2D network polymer membranes with angstrom-sized pores and thicknesses have not been reported. Herein, novel soluble 2D macromolecular sheets with angstrom-sized pores (24.6 Å) and thickness (3.4 Å) are synthesized by solid–solid interface polycondensation in laminated membranes of two cis–cisoid poly(imino-containing phenylacetylene)s followed by highly selective photocyclic aromatization (SCAT). First, a two-layered laminated polymer membrane that is self-supporting is prepared, and solid–solid interfacial polycondensation is performed. The insoluble three-dimensional (3D) network polymer layer formed is isolated by removing the soluble unreacted polymer layers. Finally, a SCAT reaction is carried out by irradiation of visible light on the insoluble 3D membrane to produce a soluble 2D macromolecular sheet. The precise 2D molecular structure can be displayed, such as the degree of polymerization, thickness, fraction of rings (pores), and pore size, estimated by GPC, AFM, 1H-NMR, IR, and XRD, because the macromolecule is soluble. Composite membranes containing the 2D macromolecular sheet show good oxygen permselectivity exceeding the Robeson upper line, possibly because the angstrom-sized pores and thicknesses produce high oxygen permselectivity without suppressing the permeability.

Synthesis and characterization of aliphatic polysulfides by interfacial polycondensation of sodium tetrasulfide with dichloroalkanes in the presence of quaternary onium salts

Poly(alkylenetetrasulfide) [poly(R-S4-R)] polymers with R = Me, Et, or Bu are prepared from alkylene dichloride and sodium tetrasulfide by an interfacial polycondensation technique using two quarternary ammonium salts as phase transfer catalysts. FT-IR, X-ray, and elemental analysis have characterized the synthesized polymers. Thermal properties were measured by thermogravimetric analysis and calorimetric differential scanning. Swelling procedure was used to investigate the solvent resistance of the polymers.

Highly Stretchable, Compressible, Resilient, and Equilibrium Swelling Hydrogels with Elastic Nano Junctions

AbstractIn this work, a flexible and polymerizable polyurethane‐urea (PUU) nanoparticle is used for the first time to prepare hydrogels showing highly stretchable, compressible, and resilient properties in their equilibrium swelling state. The PUU nanoparticles are prepared by reported interfacial polycondensation of O/W nanoemulsions followed by surface modification with acrylate groups. The hydrogels are prepared by simple free‐radical copolymerization of acrylamide and the polymerizable PUU nanoparticles. These PUU nanoparticles are expected to act as polyfunctional nanocrosslinkers and elastic junctions of the hydrogel’s network. The obtained hydrogels show high water containing character (94–97 wt%) in their equilibrium swelling state. The equilibrium swelling hydrogels can still be stretched and compressed up to 430–1170% and 95%, respectively, without fracture. Furthermore, cyclic tensile tests with a maximum strain of 500% or 700% show that the resilience of these equilibrium swelling hydrogels is as high as 95–97%. This work provides a new strategy and some new insights into the fabrication of fully swelling hydrogels with both extraordinary ductility and resilience, which is of critical importance for many of their practical applications.

Construction of polyaniline/carbon nanotubes-functionalized phase-change microcapsules for thermal management application of supercapacitors

To overcome the drawback that the electrochemical performance of supercapacitors tends to deteriorate at high working temperatures due to exothermic redox reactions during the charge–discharge process, we designed and fabricated a novel type of polyaniline (PANi)/carbon nanotubes (CNTs)-functionalized hierarchical phase-change microcapsules (MEPCM-PANi/CNTs) as a self-thermoregulatory microelectrode system. In this system, a layer-by-layer shell configuration was constructed by fabricating a SiO2 base shell onto the n-docosane core via emulsion-templated interfacial polycondensation, followed by coating a PANi/CNTs electrochemically active layer through in-situ oxidation polymerization. Such a configuration was identified by morphological observations and chemical characterizations. The resultant MEPCM-PANi/CNTs not only show a good self-regulation capability of temperature and a high latent heat-storage capacity over 140 J/g, but also present several promising advantages for thermal management applications in practice, including excellent phase-change reversibility, high working reliability, long durability, good shape stability, and high heat resistance. Most of all, the MEPCM-PANi/CNTs exhibit better supercapacitor performance than the control sample without PCM core at high working temperatures due to the effective in-situ temperature regulation and thermal management derived from their n-docosane core. Moreover, the combination of PANi and CNTs also makes contributions to an excellent pseudocapacitive behavior and good charge–discharge cycle stability due to the improvement of electric conductivity and ion-accessible specific surface in the electrochemically active layer. This study provides a new strategy for design and development of the smart self-thermoregulatory electrode materials suitably used for high-performance supercapacitors in a broader working temperature range.

Synthesis and Characterization of Linear Thermally Stable polyester contain Schiff Bases

A copolymers are important compounds today because of their wide applications in various industrial and medical fields and in other fields. Therefore, the study of preparing many of these polymers has been studied. This research involved preparing linear polyester contain Schiff-base unit by interfacial polycondensation three type diacid chloride (Succinoyl Chloride, Adipoyl Chloride and sebacoyl Chloride) in a chloroform /water system employing phase transfer catalyst with monomer containing two hydroxyl which is derived from a 4-hydroxy aniline reacted with a 4-hydroxy benzaldehyde monomer. The monomer (EM1) and polyester (EM2, EM3, and EM4) were characterized by FTIR, 1H NMR, 13C NMR and TGA analysis. The polyester–Schiff base so obtained show good thermal stability.

Application of Square and Oblong Pore Shapes in Rotating Membrane Emulsification to Produce Novel Particulate Products

Rotating membrane emulsification (RMR) has been intensively developed and applied for producing emulsion as well as particulate products such as microcapsules. Polyurea microcapsules were generally prepared by interfacial polycondensation polymerisation with addition of modifier to produce more stable microcapsules. In this research, development of the RMR was applied for producing polymer particles stabilised by nanoparticle without any addition of surfactant or modifier. Two types of membrane pores, the square (Type-A) with hydraulic diameter (Dh) of 84 mm and oblong pores with an aspect ratio of 0.33 (Type-B) having Dh of 69 mm was investigated. For the membranes designed in this research, pore shape A membrane could produce good uniformity in both polyurea microcapsule and polymer particle. In the polymer stabilised particle, this membrane type obtained a narrower size distribution than the usage for o/w emulsification. Reasonable uniform particles at high membrane rotation speed could also be achieved with the use of Type-A membrane. The uniformity confirmed that there was only minor breakup of products during operation at high membrane rotation. This attractive feature was significant in the production of fragile or shear-sensitive particulate products since the delicate structure of these products is possibly easy to destroy at high membrane rotation speed. Keywords: polyurea microcapsules; particles stabilised nanoparticles; slotted pore

Co-solvent free interfacial polycondensation and properties of polyurea PCM microcapsules with dodecanol dodecanoate as core material

A kind of eco-friendly micro-encapsulated phase change materials (MEPCM) with dodecanol dodecanoate as core material were synthesized via the interfacial polymerization of toluene-2, 4-diisocyanate (TDI) and diethylenetriamine (DETA). During the preparation, a facile solvent free synthesis route was developed owing to the good compatibility of TDI and dodecanol dodecanoate. The synthesized MEPCM were characterized by Field Emission Scanning Electron Microscopy (FE-SEM), Particle Size Distribution (PSD) analyzer, Differential Scanning Calorimetry (DSC), Thermogravimetric/Infrared spectrometry (TG-IR) and thermal constants analyzer. It is found that the resultant MEPCM in nearly spherical shape are in the size scope from 10.0 to 40.0 μm, have the average latent heat in the range of 103.4–140.3 J/g, and exhibit high temperature resistance with an onset evaporation temperature at 234.0 °C. Moreover, the MEPCM possess good thermal conductivity from 0.17 W/m K to 0.21 W/m K. Therefore, it is confirmed that the prepared MEPCM can be regarded as a promising thermal energy storage material appropriate to the thermo-regulating fields such as renewable solar heating system.

Catalytic Membrane Microreactors with an Ultrathin Freestanding Membrane for Nitrobenzene Hydrogenation.

A catalytic membrane microreactor is a potential tool for the application in multiphase catalytic reactions. Currently, the installation of a permeable ultrathin membrane to separate the reactants with different phases and the grafting of a catalyst layer on the membrane in a microreactor remain challenging. In this work, a catalytic ultrathin membrane microreactor with an ultrathin freestanding supporting membrane was developed for nitrobenzene hydrogenation, which was formed by the interfacial polycondensation reaction with parallel laminar flow in a microchannel, followed by catalyst layer immobilization on one side of the ultrathin membrane surface using the layer-by-layer self-assembly technique and in situ reduction. The ultrathin freestanding membrane ensured a stable gas/liquid contact interface and good hydrogen permeability. The developed membrane microreactor could exhibit high catalytic performance under mild conditions, demonstrating its superior mass transport. In addition, the effects of the thickness of the ultrathin freestanding membrane, flow rates, and inlet nitrobenzene concentration were investigated to obtain the optimum operating conditions. The experimental results demonstrate that this newly developed membrane microreactor is a promising candidate for multiphase catalytic reactions.

Probing the charged nature and ion-exclusion mechanism of fluorine-enriched non-ionogenic polyamide derived thin film composite nanofiltration membranes

Thin film composite (TFC) nanofiltration (NF) membrane comprising a novel fluorine-enriched polyamide (FPA) as skin layer polymer has been developed by in situ interfacial polycondensation technique.