Polyacrylate Membrane Research Articles

Facile construction of polyacrylate membranes with pendent zwitterionic side-chains for high proton conduction

Designing high-performance proton exchange membranes for fuel cells has received tremendous interests and acquired plentiful fruits. However, the complicated preparation process and consequently high cost limit their practical application. This study endeavored to facilely construct a novel type of proton exchange membrane based on polyacrylates which decorated with pendant zwitterionic groups. Chemical structure and micro-morphology of these newly prepared membranes, namely SBPA-x (x = 0, 20, 30,40), were characterized by 1HNMR, FT-IR, XPS, SEM and AFM. Swelling ratio, water uptake and ion exchange capacity were found to be positively correlated with the contents of zwitterionic groups. The hydrophilic zwitterionic groups in the membrane formed a continuous water pathway, which contributed to the proton conductivity. Particularly, SBPA-40 membrane showed the highest proton conductivity of 78.6 mS/cm and the smallest activation energy Ea as 16 kJ/mol at 80 °C and 90 % relative humidity. On the other hand, the other application properties, such as thermal stability, mechanical property and oxidation stability, were also evaluated. Results demonstrated that all the membranes possessed good thermal stability within 300 °C and presented satisfactory mechanical performance by bending and twisting. Besides, the observed power density and open circuit voltage of SBPA-40 membrane were 58.3 mW/cm2 and 0.77 V at 30 °C. In conclusion, the zwitterionic polyacrylate membranes could have prospective application in proton exchange membrane fuel cells.

Reusable and effective polyacrylic membranes for mecoprop and bentazon extractions

This study introduces reusable polyacrylic membranes, fabricated from commercially available monomers (1-vinyl-2-pyrrolidone and methylmethacrylate), as a promising approach for pesticide extraction. These membranes effectively remove the commonly used herbicides mecoprop (RE ≈ 99%) and bentazon (RE ≈ 95%) at low concentrations, which pose water contamination risks due to their water-soluble properties and leaf-level sorption. The membranes exhibit excellent manageability and resistance, allowing for safe handling without personal protective equipment. Additionally, the material is environmentally friendly and can be washed and reused for at least 4 cycles without a significant decrease in performance. Characterization techniques, including NMR, TGA, DSC, mechanical testing, N2 adsorption, and FTIR analysis, were used to investigate properties and assess the influence of the polymeric composition. The study focused on examining the lateral charged aminoethyl groups, which play a crucial role in sorbent-sorbate interactions. Sorption kinetics, isotherms, and permeation studies provided insights into the removal mechanism, efficiency, and permeability coefficients, revealing hydrophobic–hydrophobic interactions between the pesticides and the polymer. Molecular dynamics simulations revealed a scorpion-like conformation of the macromolecular chains surrounding the pesticides. These findings support the hydrophobic nature of the extraction mechanism and highlight the significant role of charged aminoethyl groups in facilitating this process.

Effect of process conditions on CO2 permeance and selectivity of polyvinyl alcohol/sodium polyacrylate membrane

ABSTRACT In this study, polymer membrane for CO2 separation was produced by blending polyvinyl alcohol and sodium polyacrylate. Tests were conducted on the produced membranes to evaluate their CO2 and He separation performance under various conditions. The optimal amount of cesium carbonate to be added to the prepared membrane in terms of separation performance was determined. It was found that the highest performance was obtained at 85°C. Effects of other process conditions such as total pressure, CO2 partial pressure, and humidity on membrane performance were also investigated. In particular, CO2 permeance of around 3.0E–10 (m3(STP)/m2 s Pa)) and selectivity of nearly 500 were observed for the separation of CO2 and helium at the CO2 partial pressure of Ptotal of 0.1 MPa. Through the above examinations, the present study was not only produced a high-performance separation membrane, but also found test conditions under which this membrane exhibited higher separation performance.

A Simple Potentiometric Biosensor based on Carboxylesterase for the Analysis of Aspartame

A potentiometric aspartame biosensor was fabricated by simply depositing the carboxylesterase (CES)-bonded poly(n-butyl acrylate-n-acryloxysuccimide) [CES-poly(nBA-NAS)] microspheres on a Ag/AgCl screen-printed pH selective electrode. The pH transducer was made from non-plasticized polyacrylate membrane containing a hydrogen ionophore and lipophilic salt. The immobilized CES enzyme catalyzed the enzymatic hydrolysis of aspartame to L-aspartic acid (L-Asp), L-phenylalanine and methanol. Potentiometric determination of aspartame concentration was performed by quantifying the hydrogen ion concentration produced from L-Asp. The potentiometric determination of aspartame exhibited good selectivity with near Nernstian response. The sensitivity of the biosensor was closed to the Nernstian value, i.e., 50-52 mV decade-1 with a dynamic linear response range from 10-5 to 10-2 M and detection limit approaching 10-6 M. The aspartame biosensor demonstrated good repeatability and reproducibility with relative standard deviation (RSD) of 1.9% and 1.6%, respectively (n=3). The potentiometric aspartame biosensor was demonstrated to be reliable for determining aspartame content in sweetener samples and was comparable to the conventional high-performance liquid chromatography (HPLC) method for aspartame analysis.

Biomimetic Modification of Water-Borne Polymer Coating with Carnauba Wax for Controlled Release of Urea.

Benefitting from the special structure of the leaf cuticle layer, plants have natural hydrophobicity and anti-fouling abilities. Inspired by the leaf surface structure, a biomimetic modification strategy was raised to improve the surface hydrophobicity of polyacrylate coating for controlled release fertilizer. Double-layer (polyacrylate and carnauba wax) coated fertilizer was obtained after biomimetic modification. The quality of controlled release fertilizer modified with the carnauba wax was greatly enhanced, and the coating material was effectively saved. The surface appearance of polyacrylate-coated fertilizer was improved for the surface blemish was repaired by the loaded carnauba wax. The characterizations by Fourier transform infrared spectroscopy indicated that the hydrogen bonds were formed between the water-based polyacrylate membrane and the carnauba wax layers. By optimizing the content of polyacrylate and carnauba wax, the release duration of the fertilizer was effectively prolonged, which was improved from 1 month to more than 2 months after the biomimetic modification. Therefore, biological wax as an environmentally-friendly natural material that has showed a broad potential in the application of coated controlled release fertilizer.

A novel chlorine-resistant polyacrylate nanofiltration membrane constructed from oligomeric phenolic resin

Conventional water treatment polyamide nanofiltration (NF) membranes often suffer from the degradation of sodium hypochlorite (NaOCl) in sewage or during the process of membrane cleaning and deteriorate the separation performance, which significantly increases the treatment cost. Herein, a novel polyacrylate composite NF membranes were prepared by interfacial polymerization using oligomeric phenolic resin (OPR) and trimesoyl chloride (TMC) as aqueous and organic phase monomer respectively on the polyethersulfone (PES) ultrafiltration supporting membranes. The fabrication parameters, including the pH of the aqueous solution, reaction time and the concentration of the monomer, on the performance of the composite NF membranes were optimized. A series of characterization indicated that the surface of the NF membranes was negatively charged, the molecular weight cut-off (MWCO) and the pore diameter of the polyacrylate membrane were 400 Da and 0.47 nm, respectively. At the optimized preparation conditions, the NF membrane exhibited high Na2SO4 rejection of 98.2% and water flux of 2.42L·m−2·h−1·bar−1, which was superior to most of the polyacrylate NF membranes reported in recent years. Compared with the polyamide membrane, the prepared polyacrylate membrane demonstrated better chlorine-resistant property and still maintained 92.0% Na2SO4 rejection after being treated with NaOCl solution. Moreover, the NF membrane preserved excellent long-term operation stability. The chlorine-resistant NF membrane constructed from OPR monomer has a broad application prospect in the field of high chlorine wastewater treatment.

Preparation of polyacrylate/silica membranes for fuel cell application by in situ UV polymerization

The development of proton conductive polyacrylate membranes based on acrylonitrile, sodium 4-vinylbenzenesulfonate, acrylic acid, ethylene glycol dimethacrylate and hybrid polyacrylate/silica membranes is reported in this article. Polyacrylate membranes were synthesized via UV-initiated copolymerization; for the synthesis of polyacrylate/silica membranes 3-methacryloxypropyl trimethoxysilane-based sol–gel system was introduced into the polymerizing mixture.

Polyarylate membrane with special circular microporous structure by interfacial polymerization for gas separation

Microporous polymer membranes have received extensive attention in the membrane separation field based on the advantage of high gas permeance and low cost. However, there are a few reports of microporous polyacrylate membranes fabricated by interfacial polymerization (IP), and the formation mechanism and influence factor of the microporous structure is rarely illuminated. In this work, thin-film polyacrylate membrane with circular microporous morphology were prepared by IP method with cyclodextrin and acyl chloride as the aqueous and oil phase monomer respectively for effective gas separation. The effects of the aqueous and organic phase monomer structure and concentration, the concentration and type of alkali in the aqueous solution on the membrane morphology and gas separation performance were investigated in detail. As a result, the polyacrylate membrane fabricated by β-cyclodextrin (β-CD) and trimesoyl chloride (TMC) with optimal content of NaOH in the aqueous phase formed the special circular microporous structure by the scanning electronic microscope (SEM) characterization. The resulting membrane showed CO2 permeance of 200 GPU with CO2/N2 ideal separation selectivity of 10.53. This work provides an effective strategy to fabricate high performance polyacrylate membrane by regulating the monomer structure and the alkali concentration in the aqueous phenol solution with IP method, which would inspire the exploration of other phenolic monomer for the assembly of microporous polymer membranes for gas separation or seawater desalination.

Synthesis of melamine-formaldehyde microcapsules containing oil-based fragrances via intermediate polyacrylate bridging layers

Abstract A general and versatile strategy to prepare melamine-formaldehyde (MF) microcapsules encapsulating oil-based fragrances by combining solvent evaporation and in situ polymerization was proposed in this work. The oil-based fragrance was pre-encapsulated by an inner polyacrylate membrane via solvent evaporation, followed by in situ polymerization of MF precondensates as an outer shell. The polyacrylate membrane is used as an intermediate bridging layer to stabilize the oil-based fragrance, and to provide driving forces for in situ polymerization of MF precondensates through electrostatic attractions between carboxyl groups and ammonium ions. It was demonstrated that MF microcapsules containing clove oil were prepared successfully. The amount and the composition of the intermediate polyacrylate bridging layer were critical. Smooth and sphere-shaped MF-clove oil microcapsules were prepared when the weight ratio of polyacrylate to clove oil was over 60 wt% and the concentration of acrylic acid (AA) increased to 10 wt% in polyacrylate. In addition, MF microcapsules containing sunflower oil and hexyl salicylate were prepared by using this method. The work suggests that this new approach can be potentially used to encapsulate various core materials, tuning the shell properties of microcapsules such as thickness, mechanical strength and release properties.

A localized surface plasmon resonance enhanced dye-based biosensor for formaldehyde detection

A novel dye-based biosensor with Au nanoparticles (Au NPs) for formaldehyde detection was fabricated with a simple method. Au NPs were grown on a glass substrate and then coated with a polyacrylate membrane film containing chromoionophore I (ETH 5294) and the alcohol oxidase enzyme (AOX). The analytical principle of biosensors is based on the color change of dye chromoionophore due to photoexcitation of electrons upon the selective binding with H+ ions resulted from the enzymatic oxidation reaction of formaldehyde. The presence Au NPs has improved the performance of biosensors may be due to the enhanced scattering light around Au NPs in the vicinity of cromoionophore that was used to photoexcite more electrons of cromoionophore. The biosensor also displays good selectivity to formaldehyde when tested with acetaldehyde and methanol, reproducibility (RSD of 1.8%), and repeatability (RSD of 3.3%) and a lifetime of 21days.

Research on flux decline in nanofiltration of lactic acid solutions with ZRIV/PAA membranes application

Abstract The efficiency of lactic acid solutions nanofiltration with dynamically formed zirconium (IV) hydrous oxide polyacrylate (ZrIV/PAA) membranes application were considered in this paper. The results of investigations on flux decline in nanofiltration of lactic acid solutions under conditions resulting in low and high lactic acid rejection are reported. In the long term experimental research on pressure driven membrane processes the main reason of permeate flux reduction is an accumulation of concentration polarization and fouling effects. The experimental permeate flux versus time curves were analyzed in the frame of resistance-in-series model with the aim to develop the characteristic fouling and concentration polarization resistances. The analysis of experimental data and results of calculations showed that both: concentration polarization and fouling phenomena in investigated system depend on hydrodynamic conditions and properties of filtered solutions and (ZrIV/PAA) membrane.

Structure and Hydrogen Bonding of Water in Polyacrylate Gels: Effects of Polymer Hydrophilicity and Water Concentration.

The ability to tune the hydrophilicity of polyacrylate copolymers by altering their composition makes these materials attractive candidates for membranes used to separate alcohol-water mixtures. The separation behavior of these polyacrylate membranes is governed by a complex interplay of factors such as water and alcohol concentrations, water structure in the membrane, polymer hydrophilicity, and temperature. We use molecular dynamics simulations to investigate the effect of polymer hydrophilicity and water concentration on the structure and dynamics of water molecules in the polymer matrix. Samples of poly(n-butyl acrylate) (PBA), poly(2-hydroxyethyl acrylate) (PHEA), and a 50/50 copolymer of BA and HEA were synthesized in laboratory, and their properties were measured. Model structures of these systems were validated by comparing the simulated values of their volumetric properties with the experimental values. Molecular simulations of polyacrylate gels swollen in water and ethanol mixtures showed that water exhibits very different affinities toward the different (carbonyl, alkoxy, and hydroxyl) functional groups of the polymers. Water molecules are well dispersed in the system at low concentrations and predominantly form hydrogen bonds with the polymer. However, water forms large clusters at high concentrations along with the predominant formation of water-water hydrogen bonds and the acceleration of hydrogen bond dynamics.

Thermal post-treatment alters nutrient release from a controlled-release fertilizer coated with a waterborne polymer.

Controlled-release fertilizers (CRF) use a controlled-release technology to enhance the nutrient use efficiency of crops. Many factors affect the release of nutrients from the waterborne polymer-coated CRF, but the effects of thermal post-treatments remain unclear. In this study, a waterborne polyacrylate-coated CRF was post-treated at different temperatures (30 °C, 60 °C, and 80 °C) and durations (2, 4, 8, 12, and 24 h) after being developed in the Wurster fluidized bed. To characterize the polyacrylate membrane, and hence to analyze the mechanism of nutrient release, Fourier transform mid-infrared spectroscopy, scanning electron microscopy, and atomic force microscopy were employed. The nutrient-release model of CRF post-treated at 30 °C was the inverse “L” curve, but an increased duration of the post-treatment had no effect. The nutrient-release model was “S” curve and nutrient-release period was enhanced at higher post-treatment temperatures, and increased post-treatment duration lengthened slowed nutrient release due to a more compact membrane and a smoother membrane surface as well as a promoted crosslinking action. CRF equipped with specified nutrient-release behaviors can be achieved by optimizing the thermal post-treatment parameters, which can contribute to the development and application of waterborne polymer-coated CRF and controlled-release technologies.

Biodegradation of a biochar-modified waterborne polyacrylate membrane coating for controlled-release fertilizer and its effects on soil bacterial community profiles.

Biochar-modified polyacrylate-like polymers are promising waterborne polymer-based membrane coatings for controlled-release fertilizers. However, the effect of these membrane polymers on paddy soil is unknown. A soil incubation experiment was conducted using Fourier transform infrared photoacoustic spectroscopy to monitor the changes in the polymer-coated membranes in paddy soil, and Biolog EcoPlates and polymerase chain reaction-denaturing gradient gel electrophoresis were used to detect the effects of the membranes on soil bacterial community profiles. Compared to unmodified membranes, the biodegradation rate of the biochar-modified membrane was slower, and the membrane was more intact, which improved and guaranteed the controlled release of nutrients. Compared to the soil without membranes, the biochar-modified membranes, as well as unmodified ones, showed no significant impacts on the composition diversity of soil dominant bacterial community. The activity and functional diversity of soil culturable microbial community during the early stage of incubation were reduced by biochar-modified membranes due to the release of small amount of soluble organic materials but were both recovered in the 12(th) month of the incubation period. Therefore, the biochar-modified waterborne polyacrylate was environmentally friendly, demonstrating its potential both in the development of coated controlled-release fertilizers and in the utilization of crop residue.

Wafer-scale fabricated thermo-pneumatically tunable microlenses

We have developed a self-contained, liquid tunable microlens based on polyacrylate membranes integrated with compact on-chip thermo-pneumatic actuation fabricated using full-wafer processing. Silicone oil is used as the optical liquid, which is pushed or pulled into the lens cavity via an extended microfluidic channel structure without any pumps, valves or other mechanical means. The heat load generated by the thermal actuator is physically isolated from the lens chamber. The back focal length may be tuned from infinity to 4 mm with a maximum power consumption of 300 mW. The principal application is fine tuning of the back focal length, for which tuning time constants as small as 100 ms are suitable.

Fabrication of monodisperse hollow silica spheres and effect on water vapor permeability of polyacrylate membrane

Polystyrene/silica core–shell spheres were fabricated using polystyrene as templates by hydrolysis and condensation of tetraethyl orthosilicate through a sol–gel process, in which polystyrene was synthesized by emulsion polymerization. Then, hollow silica spheres were obtained after selective removal of the organic polystyrene core from the polystyrene/silica core–shell spheres by tetrahydrofuran etching. The effect of hollow silica spheres on water vapor permeability, mechanical property, and water uptake of polyacrylate membrane were investigated. The microstructure analysis shows that the mean size and wall thickness of hollow silica spheres are 170nm and 20nm, respectively. The silica shells consist of amorphous silica seed assembly with a broad size distribution, which roughen the surfaces of hollow silica spheres greatly. The specific surface area of hollow silica spheres is bigger than that of polystyrene/silica core–shell spheres. Hollow silica spheres can significantly improve water vapor permeability of polyacrylate membrane, but lead to the reduction in mechanical property.

Polyacrylate membranes for tunable liquid-filled microlenses

We present the use of polyacrylate membranes for the fabrication of pneumatically actuated variable lenses. Whereas the most commonly used membrane material for tunable liquid-filled lenses is polydimethylsiloxane (PDMS), polyacrylate membranes have the advantages of high resistance to swelling in silicone oil and enhanced compatibility with a wide range of aqueous optical liquids. These features are quantitatively demonstrated by comparing the material properties and performance of PDMS and polyacrylate membrane lenses. The optical transparency of polyacrylate is more than 92%. The surface roughness is below 3.3 nm rms, and reversible elastic deformation could be demonstrated. Optical measurements show that the cutoff frequency of the modulation transfer function of polyacrylate lenses with different liquid fillings, using a reference contrast of 0.2, is more than 1.5 times larger than that of the same system assembled with PDMS membranes filled with water.

Solid-state reference electrodes based on carbon nanotubes and polyacrylate membranes.

A novel potentiometric solid-state reference electrode containing single-walled carbon nanotubes as the transducer layer between a polyacrylate membrane and the conductor is reported here. Single-walled carbon nanotubes act as an efficient transducer of the constant potentiometric signal originating from the reference membrane containing the Ag/AgCl/Cl− ions system, and they are needed to obtain a stable reference potentiometric signal. Furthermore, we have taken advantage of the light insensitivity of single-walled carbon nanotubes to improve the analytical performance characteristics of previously reported solid-state reference electrodes. Four different polyacrylate polymers have been selected in order to identify the most efficient reservoir for the Ag/AgCl system. Finally, two different arrangements have been assessed: (1) a solid-state reference electrode using photo-polymerised n-butyl acrylate polymer and (2) a thermo-polymerised methyl methacrylate:n-butyl acrylate (1:10) polymer. The sensitivity to various salts, pH and light, as well as time of response and stability, has been tested: the best results were obtained using single-walled carbon nanotubes and photo-polymerised n-butyl acrylate polymer. Water transport plays an important role in the potentiometric performance of acrylate membranes, so a new screening test method has been developed to qualitatively assess the difference in water percolation between the polyacrylic membranes studied. The results presented here open the way for the true miniaturisation of potentiometric systems using the excellent properties of single-walled carbon nanotubes.

Lowering the Resistivity of Polyacrylate Ion-Selective Membranes by Platinum Nanoparticles Addition

The effect of platinum nanoparticles introduction into polyacrylate membranes was examined. Platinum nanoparticles were added to the membrane cocktail before photopolymerization of the poly(n-butyl acrylate) based ion-selective membranes. Thus obtained sensors were characterized with significantly lowered electrical resistance and increased stability of potential readings compared to classical poly(n-butyl acrylate) membranes. The analytical parameters of platinum nanoparticle containing membranes were well comparable with those of classical membranes.

A Potentiometric Formaldehyde Biosensor Based on Immobilization of Alcohol Oxidase on Acryloxysuccinimide-modified Acrylic Microspheres

A new alcohol oxidase (AOX) enzyme-based formaldehyde biosensor based on acrylic microspheres has been developed. Hydrophobic poly(n-butyl acrylate-N-acryloxy-succinimide) [poly(nBA-NAS)] microspheres, an enzyme immobilization matrix, was synthesized using photopolymerization in an emulsion form. AOX-poly(nBA-NAS) microspheres were deposited on a pH transducer made from a layer of photocured and self-plasticized polyacrylate membrane with an entrapped pH ionophore coated on a Ag/AgCl screen printed electrode (SPE). Oxidation of formaldehyde by the immobilized AOX resulted in the production of protons, which can be determined via the pH transducer. Effects of buffer concentrations, pH and different amount of immobilization matrix towards the biosensor’s analytical performance were investigated. The formaldehyde biosensor exhibited a dynamic linear response range to formaldehyde from 0.3–316.2 mM and a sensitivity of 59.41 ± 0.66 mV/decade (R2 = 0.9776, n = 3). The lower detection limit of the biosensor was 0.3 mM, while reproducibility and repeatability were 3.16% RSD (relative standard deviation) and 1.11% RSD, respectively (n = 3). The use of acrylic microspheres in the potentiometric formaldehyde biosensor improved the biosensor’s performance in terms of response time, linear response range and long term stability when compared with thick film immobilization methods.