Monomer Phase Research Articles

Interfacial Pickering Emulsion Polycondensation for Degradable Nanocomposites.

Pickering emulsion polymerization is a practical method to fabricate functional composite materials. However, most reported systems proceed homogeneously within the stabilized monomer phase and create nondegradable chemical bonds. Here, interfacial Pickering emulsion polycondensation between aromatic aldehydes and polymercaptans is developed using sustainable cellulose nanoparticles as the stabilizer. When sulfonated cellulose nanocrystals (S-CNCs) were utilized, they also catalyzed the polycondensation to produce the oxidatively degradable S,S-acetal groups on the polymer chains. The influence of monomer and cellulose structures on the polymerization behavior and composite properties were compared.

Hydrogel granular systems for controlled release based on (co)polymers of 2-hydroxyethyl methacrylate with polyvinylpyrrolidone (a review)

The development of polymer carriers for systems of prolonged and controlled release of substances, particularly drugs, into the action environment is a relevant task in polymer chemistry and technology. This aims to solve the problem of reducing the effective dose of a medical drug administered into the body of a person or animal. The latest achievements in the field of creating such carriers in the form of spherical particles based on 2-hydroxyethyl methacrylate and polyvinylpyrrolidone (co)polymers are analyzed and summarized. The working principles and advantages of such systems are described. The research of the synthesis regularities, structure, properties and perspectives of application of granular hydrogels based on 2-hydroxyethyl methacrylate and its copolymers with polyvinylpyrrolidone was analyzed. The mixture of decanol and cyclohexanol as a solvent for the monomer phase is substantiated. Based on the analysis of kinetic studies, the optimal technological parameters for the suspension polymerization of 2-hydroxyethyl methacrylate with polyvinylpyrrolidone were selected, and the possibility of regulating the dispersion characteristics of copolymers via changes in the technological synthesis modes was confirmed. The results of studies on the sorption-desorption properties of copolymers concerning model substances and drugs are described. The possibility of directed regulation of sorption capacity and drug release rate through changes in copolymer composition was confirmed. Methods for increasing the sorption capacity of hydrogels for drugs are proposed.

Thermally stable thin-film composite nanofiltration membranes derived from 3,3′-diaminobenzidine

The rapid development of modern industrialization has put forward high demands on separation and purification technologies. To reduce energy consumption, improve efficiency, and enhance process flexibility, nanofiltration membranes for high temperature separation have become more and more important. Herein, we report the use of 3,3′-diaminobenzidine (DAB) as the aqueous phase monomer and trimesoyl chloride (TMC) as the organic phase monomer to engineer thermally resistant nanofiltration membranes via interfacial polymerization. The incorporation of DAB enhances the rigidity of the cross-linked polyamide network, reduces segmental thermal motion at high temperature, and improves the thermal stability of the composite membrane. The variations in fractional free volumes of the nanofiltration membranes were analyzed at different temperatures by molecular dynamics (MD) simulation, which have also been confirmed by experiments. The findings reveal that incorporating a rigid monomer into the polyamide layer can significantly enhance the thermal resistance. The resultant composite membrane exhibits outstanding resistance to high-temperature feed solutions, boasting a highly stable rejection rate (97.0 %) to Na2SO4 between 25–85 °C. Remarkably, even under sustained operation at 85 °C for 12 h, the rejection rate is consistently stable. This work presents a novel system for the design of thermally stable nanofiltration membranes for high temperature separation.

Differences Photopolymerizations and Characterizations of Monomers Liquid Crystal between Mesogen Reactive RM 257 and Cholesteryl Acrylate using method of UV Curing

Abstract Mesogen reactive RM257 and cholesteryl acrylate are two types of liquid crystal with the characteristic property of possesing polymerizable groups. Cholesteryl acrylate has interesting properties that can form a helical spiral structure. Previous research in maintaining the helical structure has not been maximized. In this study, we will explain how the UV curing process is a way to fix the helical structure. Monomer phase of cholesteryl acrylate only appears at mesophase temperature, in order to maintain the helical structure of the cholesterl acrylic compound is polymerized. Mesogen reactive RM257 is monomer liquid crystal that acrylate functions as back bone polymer chain. Cholesteryl acrylate and RM257 each monomers is polymerized using UV light with 55 watt of wavelength which has 365 nm. The polymerization process produces a new functional group formed by C-O esters at wave numbers 1047 cm−1 and 1055 cm−1. XRD diffraction pattern showed peaks at 2θ in 7.5°,15°, and 20°. Photo SEM image showed crosslinked morphology structure. Based on the results of this study, it is hoped that the polymer RM257 and acrylate coliform can be smart materials for sensor applications and further technological material composites.

Modulating interfacial polymerization by combination of organic phase additives and trimesoyl chloride for preparing high-performance thin-film nanocomposite reverse osmosis membranes

Incorporating hydrophilic nanoparticles into organic phase during interfacial polymerization (IP) to establish covalent bonds with organic phase monomers has proven to be a successful approach for fabricating high-performance thin-film nanocomposite (TFN) reverse osmosis (RO) membranes. However, the effect of covalent bonds number on the membrane structure and properties remains uncertain. Herein, hydrochloric acid doped polyaniline (PANI-HCl) with a small amount of amine groups and inherent polyaniline (PANI-base) nanomaterials with a larger amount of amine groups were prepared as organic phase additives for preparing high-performance TFN RO membranes. The amine groups on the nanoparticles can bond covalently with the acyl chloride groups of trimethyl chloride (TMC), leading to the accumulation of TMCs at organic/aqueous interface and accelerates IP reaction rate, resulting in a thinner, denser polyamide layer with more leaf-like structures and free volume. The water permeance of the PANI-base-RO membrane was improved by 62.5 % from 0.8 to 1.3 Lm−2h−1bar−1, and the NaCl rejection was improved from 97.6 % to 99.4 % compared with the pristine membrane. Overall, this work highlights the beneficial impact of organic phase additives with more amine groups on enhancing the desalination performance of RO membranes, providing valuable insights for the structural design of additives and dispersing medium selection.

Synergistic preparation of organic solvent nanofiltration membranes from polydopamine/polyethyleneimine interlayers with aminated attapulgite

This study utilized polydopamine (PDA)/polyethyleneimine(PEI) as the hydrophilic interlayer and added aminated attapulgite (ATP-NH2) to the aqueous phase monomer for interfacial polymerization (IP) to synergistically create nanofiltration membranes resistant to organic solvents. The hydrophilic nature of the PDA/PEI interlayer facilitates the rapid passage of polar solvents and results in excellent adhesion, ensuring tight bonding between the ultrafiltration support membranes and the active layer. Furthermore, the incorporation of the ATP-NH2 nanoparticles played a pivotal role in regulating the IP process. The resulting nanofiltration membranes, produced through the combined efforts of these components, achieved an optimal methanol permeation flux of 14.05 L m−2h−1 bar−1, with a rejection rate of Evans blue dye maintained at 99.42 %. Despite being exposed to N, N-dimethylformamide (DMF) at 80 ℃ for a period of 5 days, the nanofiltration membranes maintained both their exceptional separation effectiveness and stability. These findings suggest promising application prospects for the developed nanofiltration membranes.

Dual-phase microporous polymer nanofilms by interfacial polymerization for ultrafast molecular separation.

Fine-tuning microporosity in polymers with a scalable method has great potential for energy-efficient molecular separations. Here, we report a dual-phase molecular engineering approach to prepare microporous polymer nanofilms through interfacial polymerization. By integrating two micropore-generating units such as a water-soluble Tröger's base diamine (TBD) and a contorted spirobifluorene (SBF) motif, the resultant TBD-SBF polyamide shows an unprecedentedly high surface area. An ultrathin TBD-SBF membrane (~20 nm) exhibits up to 220 times improved solvent permeance with a moderate molecular weight cutoff (~640 g mol-1) compared to the control membrane prepared by conventional chemistry, which outperforms currently reported polymeric membranes. We also highlight the great potential of the SBF-based microporous polyamides for hydrocarbon separations by exploring the isomeric effects of aqueous phase monomers to manipulate microporosity.

Fabrication of self-cleaning nanofiltration membranes through interfacial polymerization using PEI@CoPc monomer for Mg2+/Li+ separation

Efficient Mg2+/Li+ separation is highly demanded to address the global lithium scarcity. The nanofiltration (NF) membrane prepared with PEI-based monomer possess positively charged surface, exhibiting promise potential in lithium extraction from salt lake brines. In this work, water-soluble metal phthalocyanine (PEI@CoPc) was synthesized via grafting reaction between PEI and the (Tetracarboxyphthalocyaninato)cobalt(Ⅱ). The light-responsive NF membrane was prepared via interfacial polymerization technique using the water-soluble PEI@CoPc as aqueous phase monomer alone. This strategic modification significantly enhances the water permeance and Mg2+/Li+ selectivity of the membrane. The best-performing of PEI@CoPc-TMC/PES membrane shows a water permeance of 16.7 L m-2h−1 bar−1 and a Mg2+/Li+ selectivity of 29.5. The membranes exhibited exceptional selectivity towards magnesium ions while maintaining high lithium permeability, offering effective technical support for the efficient extraction of lithium resources from salt-lake brines. Moreover, the distinctive photocatalytic activity of PEI@CoPc can generate active oxidizing species such as superoxide radicals (•O2–) to oxidatively degrade pollutants, conferring the membrane excellent self-cleaning capability. The results indicated that the prepared composite membrane exhibit excellent fouling resistance and self-cleaning performance.

Preparation of self-healing and pH-responsive nanofiltration membranes with improved anti-fouling property for salt/dye separation

Nanofiltration (NF) membranes can inevitably suffer from external damage in the practical application process, causing the loss of their original function and performances. In this work, the β-CD-DX-S were synthesized for the first time through one-step polymerization of SBMA, DMAEMA and double bond functionalized β-CD. Subsequently, the membrane was successfully fabricated via interfacial polymerization using the constructed β-CD-DX-S as aqueous phase monomer alone. The prepared β-CD-DX-S/PES membrane exhibits novel self-healing performance attributing to the host-guest interaction between DMAEMA and β-CD. The membranes also possess excellent pH-responsive property attributing to the protonation and deprotonation behavior under different pH environments of dimethylamine unit in DMAEMA. The grafted DMAEMA and SBMA enhanced the hydrophilic property of membrane, reducing electrostatic adsorption of pollutants on the surface of membrane. The hydrophobic binding site inside the cavity of β-CD can accommodate dimethylamino group in the DMAEMA which could be regulate the spatial structure of β-CD-based materials, strengthening salt/dye selectivity of membrane. The results indicated that the prepared β-CD-DX-S/PES membranes possess good potential for NF applications.

The regulatory mechanism of rapid lignification for timely anther dehiscence.

Anther dehiscence is a crucial event in plant reproduction, tightly regulated and dependent on the lignification of the anther endothecium. In this study, we investigated the rapid lignification process that ensures timely anther dehiscence in Arabidopsis. Our findings reveal that endothecium lignification can be divided into two distinct phases. During Phase I, lignin precursors are synthesized without polymerization, while Phase II involves simultaneous synthesis of lignin precursors and polymerization. The transcription factors MYB26, NST1/2, and ARF17 specifically regulate the pathway responsible for the synthesis and polymerization of lignin monomers in Phase II. MYB26-NST1/2 is the key regulatory pathway responsible for endothecium lignification, while ARF17 facilitates this process by interacting with MYB26. Interestingly, our results demonstrate that the lignification of the endothecium, which occurs within approximately 26 h, is much faster than that of the vascular tissue. These findings provide valuable insights into the regulation mechanism of rapid lignification in the endothecium, which enables timely anther dehiscence and successful pollen release during plant reproduction.

Ethanol activation of polyester membrane for superior dye/salt separation performance

Dye wastewater poses a severe danger to the environment and human health. The purification of dye wastewater is the focus and hotspot of most researchers. In this work, ethylene glycol (EG) was selected as an aqueous phase monomer to fabricate polyester membranes through an interfacial polymerization reaction. Then the polyester membrane was activated by ethanol aqueous solution. By adjusting the activation time and concentration of the ethanol, the network of the polyester membrane can be reshaped to endow the membrane with excellent performance. The activation mechanism was also explored here. Compared to the membrane without activation (PE-0%), the permeability of the optimized membrane (PE-40%) was increased by 8.3 times, and a high rejection was maintained (CR: 99.2%). Importantly, the PE-40% membrane also presented good acid and alkali resistance, chlorine resistance, and excellent antifouling performance. Our work provides an effective and feasible strategy for the development of high-performance polyester membranes.

Mechanical Properties of Polydiacetylene Multilayers Studied by AFM Force Spectroscopy.

The blue-to-red chromatic phase transition of polydiacetylene (PDA) is accompanied by the twist and rearrangement of its side chains, which results in shortening of the conjugation length in the backbone. However, how these morphological changes affect its mechanical properties remains elusive. In this work, force spectroscopy mapping by atomic force microscopy was employed to quantify mechanical parameters of PDA thin films such as breakthrough force and Young's modulus at the monomer, blue, and red phases during the chromatic transition. We found that the breakthrough force increased by 113% and Young's modulus decreased by 21% during the blue-to-red transition, highlighting that the subtle change in the side-chain configuration has a dramatic impact on its mechanical properties.

Micropore engineering of polyamide loose nanofiltration membrane for efficient dye/salt separation

Loose nanofiltration membranes (LNF) with efficient sieving and excellent permeance are desirable for dye/salt separation, and engineering the micropore of the LNF membranes is a promising approach to maximize membrane performance. Herein, we present a highly permeable and sieving polyamide LNF membrane with high porosity and suitable pore size that is prepared by interfacial polymerization using twisted aqueous phase monomer and subsequent alkali-treatment. The large-size, rigid and twisted structure of the adamantane-1,3-diamine effectively inhibits the dense-packing of polymer chain segments, resulting in a polyamide membrane with enhanced porosity and enlarged pore size. The alkali treatment hydrolyzes the partial amide linkage to further enlarge the membrane pore size, increasing the flux while maintaining high dye rejection. The optimum membrane exhibits a high salt/dye selective factor of 735 for Na2SO4/Evans blue and an excellent water permeance of 87.72 L m−2 h−1 bar−1. This study is expected to provide a valuable guidance for the targeted design and fabrication of LNF membranes.

Synergistic interfacial polymerization between hydramine/diamine and trimesoyl chloride: A novel reaction for NF membrane preparation

Polyester-amide (PEA) thin film composite (TFC) NF membranes have rapidly evolved towards a competitive performance, benefiting from their remarkable antifouling capability and superior chlorine resistance. In this report, a new concept of synergistic interfacial polymerization is explored, which promptly triggers the reaction between hydramines and trimesoyl chloride (TMC) in the presence of a trace amount of diamines. This rapid-start mode enables the formation of defect-free PEA films without the requirement of catalysis. A comprehensive characterization of physicochemical properties using high-resolution mass spectrometer (HRMS) reveals that the recombination and formation of a “hydramine-diamine” coupling unit plays a decisive role in activating the synergistic interfacial polymerization reaction with TMC molecules. Taking the pair of serinol and piperazine (PIP) as an example, the PEA-NF membrane fabricated with 0.1 w/v% serinol mixed with 0.04 w/v% PIP as water-soluble monomer and 0.1 w/v% TMC as oil phase monomer was found to have a pure water permeability (PWP) of 18.5 L·m−2·h−1·bar−1 and a MgSO4 rejection of 95.5 %, which surpasses almost all the reported PEA NF membranes. Findings of the current research provide more possibilities for the low-cost and rapid synthesis of high-performance PEA membranes aiming for water purification.

Quaternary phosphonium-polyamide membranes for efficient lithium extraction from brine sources

Lithium extraction from brine sources such as salt lakes, seawater, and produced water from oil/gas fields is garnering increasing interests from the academic and industrial sectors due to its cost-effectiveness and reduced environmental impact. A critical technological challenge is the efficient separation of Mg2+ and Li+ ions. Many researchers have reported the preparation of positively charged nanofiltration membranes with quaternary ammonium groups, yet investigations about quaternary phosphonium groups are scarce. In this work, positively charged nanofiltration membranes were prepared utilizing polyethyleneimine as the aqueous phase monomer, trimesoyl chloride as the organic phase monomer, and 3-bromopropyl triphenyl phosphonium bromide as the functionalizing monomer. The TFC-P+ membranes, enriched with a high density of quaternary phosphonium groups and an enhanced Donnan effect, achieve a MgCl2 rejection of 98.9 %, a Mg2+/Li+ selectivity of 81.6, and a water flux of 50 LMH under 0.5 MPa. The membranes possess an enhanced comprehensive separation capability that exceeds that of the majority of nanofiltration membranes documented in scholarly articles. Additionally, the membranes exhibit outstanding anti-fouling and anti-bacterial characteristics, essential for their industrial applications. The preparation method proposed herein is simple and conducive to continuous production processes. In light of the abundant produced water reserves from oil and gas extraction, future work will focus on pilot-scale lithium extraction experiments.

Enantiomeric separation of tryptophan via novel chiral polyamide composite membrane.

The separation of chiral drugs continues to pose a significant challenge. However, in recent years, the emergence of membrane-based chiral separation has shown promising effectiveness due to its environmentally friendly, energy-efficient, and cost-effective characteristics. In this study, we prepared chiral composite membrane via interfacial polymerization (IP), utilizing β-cyclodextrin (β-CD) and piperazine (PIP) as mixed monomers in the aqueous phase. The chiral separation process was facilitated by β-CD, serving as a chiral selective agent. The resulting membrane were characterized using SEM, FT-IR, and XPS. Subsequently, the chiral separation performance of the membrane for DL-tryptophan (Trp) was investigated. Lastly, the water flux, dye rejection, and stability of the membrane were also examined. The results showed that the optimized chiral PIP0.5β-CD0.5 membrane achieved an enantiomeric excess percentage (ee%) of 43.0% for D-Trp, with a solute flux of 66.18 nmol·cm-2·h-1, and maintained a good chiral separation stability. Additionally, the membrane demonstrated positive performance in the selective separation of mixed dyes, allowing for steady operation over a long period of time. This study offers fresh insights into membrane-based chiral separations.

Controlled Supramolecular Polymerization via Bioinspired, Liquid-Liquid Phase Separation of Monomers.

Dynamic supramolecular assemblies, driven by noncovalent interactions, pervade the biological realm. In the synthetic domain, their counterparts, supramolecular polymers, endowed with remarkable self-repair and adaptive traits, are often realized through bioinspired designs. Recently, controlled supramolecular polymerization strategies have emerged, drawing inspiration from protein self-assembly. A burgeoning area of research involves mimicking the liquid-liquid phase separation (LLPS) observed in proteins to create coacervate droplets and recognizing their significance in cellular organization and diverse functions. Herein, we introduce a novel perspective on synthetic coacervates, extending beyond their established role in synthetic biology as dynamic, membraneless phases to enable structural control in synthetic supramolecular polymers. Drawing parallels with the cooperative growth of amyloid fibrils through LLPS, we present metastable coacervate droplets as dormant monomer phases for controlled supramolecular polymerization. This is achieved via a π-conjugated monomer design that combines structural characteristics for both coacervation through its terminal ionic groups and one-dimensional growth via a π-conjugated core. This design leads to a unique temporal LLPS, resulting in a metastable coacervate phase, which subsequently undergoes one-dimensional growth via nucleation within the droplets. In-depth spectroscopic and microscopic characterization provides insights into the temporal evolution of disordered and ordered phases. Furthermore, to modulate the kinetics of liquid-to-solid transformation and to achieve precise control over the structural characteristics of the resulting supramolecular polymers, we invoke seeding in the droplets, showcasing living growth characteristics. Our work thus opens up new avenues in the exciting field of supramolecular polymerization, offering general design principles and controlled synthesis of precision self-assembled structures in confined environments.

Preparation of a Porous Protein-Based Composite Material by In Situ Polymerization of Pickering High Internal Phase Emulsion for Adsorption of Lead Ions.

The preparation of complex porous materials using a small molecular surfactant as the stabilizer of a high internal phase emulsion can result in harm to the environment. In this study, porous composites based on soy protein isolate with poly(acrylic acid) were prepared by in situ polymerization of a high internal phase monomer emulsion with an internal phase volume fraction of 80%. The material was prepared from acrylic acid and an N,N-methyl diacrylic acid monomer solution as the continuous phase, peanut oil as the dispersed phase, and soy protein isolate as the composite stabilizer. Scanning electron microscopy showed that porous composites exhibited a concave/convex three-dimensional interpenetrating pore structure. Fourier-transform infrared spectra revealed the existence of many active groups such as carboxyl, amino, hydroxyl, and sulfhydryl. The composite had a high adsorption capacity for lead ions, even at low concentration, with a removal rate of up to 95.7%. The adsorption process conformed to a two-stage model involving internal diffusion and Langmuir isothermal adsorption. The maximum saturated adsorption capacity was 36.71 mg/g when the initial solution concentration was 150 mg/L, the adsorbent concentration was 7.0 g/L, and the adsorption mechanism involved chemical interactions between the lead ions and the composite groups -COOH, -OH, and -SH.

Functionally Gradient Macroporous Polymers: Emulsion Templating Offers Control over Density, Pore Morphology, and Composition.

Gradient macroporous polymers were produced by polymerization of emulsion templates comprising a continuous monomer phase and an internal aqueous template phase. To produce macroporous polymers with gradient composition, pore size, and foam density, we varied the template formulation, droplet size, and internal phase ratio of emulsion templates continuously and stacked those prior to polymerization. Using the outlined approach, it is possible to vary one property along the resulting macroporous polymer while retaining the other properties. The elastic moduli and crush strengths change along the gradient of the macroporous polymers; their mechanical properties are dominated by those of the weakest layers in the gradient. Macroporous polymers with gradient chemical composition and thus stiffness provide both high impact load and energy adsorption, rendering the gradient foam suitable for impact protective applications. We show that dual-dispensing and simultaneous blending of two different emulsion formulations in various ratios results in a fine, bidirectional change of the template composition, enabling the production of true gradient macroporous polymers with a high degree of design freedom.

A sub-10 nm polyamide nanofiltration membrane from polyvinylpyrrolidone-mediated interfacial polymerization

In conventional interfacial polymerization (IP) for thin-film composite nanofiltration membranes, the separation layer is typically thick (∼100 nm), which limits its water permeance. In this study, we successfully synthesized an ultrathin polyamide layer (∼8.6 nm) from polyvinylpyrrolidone (PVP)-mediated IP. With the surfactant concentration over its critical micelle concentration, PVP not only formed a monolayer at the water-heptane interface, but also stayed in the aqueous solution. The CO groups of PVP formed the N–H⋯O hydrogen bond interactions with N–H bonds of piperazine (PIP) monomers in the aqueous phase to slow down the diffusion of PIP monomers. Besides, PVP with amphiphilic groups minimized the interfacial tension at the water-heptane interface to regulate IP processes. By adjusting the concentration of PVP, we obtained a sub-10 nm polyamide nanofiltration membrane. Moreover, hydrophilic PVP macromolecules improved the membrane surface hydrophilicity. Due to the ultrathin thickness and improved hydrophilicity, the optimized polyamide membrane demonstrated a threefold increase in permeance compared to that of the pristine polyamide membrane without PVP addition, and maintained 98.4% rejection for 1000 ppm Na2SO4 solution. This study provides a new insight into fabricating sub-10 nm polyamide membranes for nanofiltration processes.