Conventional Phase Separation Research Articles

A Differential Protein Study on Bronchoalveolar Lavage Fluid at Different Stages of Silicosis.

In this study, by comparing the difference in protein expression in bronchoalveolar lavage fluid between silicosis patients in different stages and healthy controls, the pathogenesis of pneumoconiosis was discussed, and a new idea for the prevention and treatment of pneumoconiosis was provided. The lung lavage fluid was pretreated by 10 K ultrafiltration tube, Agilent 1100 conventional liquid phase separation, strong cation exchange column (SCX) HPLC pre-separation, and C18 reverse phase chromatography desalting purification, and protein was labeled with isotope. GO, KEGG pathway, and PPI analysis of differential proteins were conducted by bioinformatics, and protein types and corresponding signal pathways were obtained. Thermo Q-Exactive mass spectrometry identified 943 proteins. T-test analysis was used to evaluate the different significance of the results, and the different protein of each group was obtained by screening with the Ratio≥1.2 or Ratio≤0.83 and P<0.05. We found that there are 16 kinds of protein throughout the process of silicosis. There are different expressions of protein in stages Ⅲ/control, stages Ⅱ/control, stage Ⅰ/control, stages Ⅲ/ stages Ⅱ, stages Ⅲ/ stage Ⅰ and stages Ⅱ/ stage Ⅰ groups. The results of ontology enrichment analysis of total differential protein genes show that KEGG pathway enrichment analysis of differential protein suggested that there were nine pathways related to silicosis. The main biological changes in the early stage of silicosis are glycolysis or gluconeogenesis, autoimmunity, carbon metabolism, phagocytosis, etc., and microfibril-associated glycoprotein 4 may be involved in the early stage of silicosis. The main biological changes in the late stage of silicosis are autoimmunity, intercellular adhesion, etc. Calcium hippocampus binding protein may participate in the biological changes in the late stage of silicosis. It provides a new idea to understand the pathogenesis of silicosis and also raises new questions for follow-up research.

Polyurethane toughened covalent adaptive networks epoxy composite based on thermoreversible Diels‐Alder reaction: Self‐healable, shape memory, and recyclable

AbstractCovalent adaptive networks (CANs) epoxy based on the Diels‐Alder (DA) reaction usually are commonly used for self‐healing materials. However, poor toughness greatly limits its application in innovative materials. Herein, based on retaining the excellent dynamic characteristics of DA reactive CANs, we introduced thermoplastic polyurethane (TPU) in situ during crosslinking, improving the composite material's strength and toughness. A multicomponent polymeric system with advanced performance can be produced by the individual components on the condition of the synergistic hybrid effects. Molecular‐level interlocking polymer networks between the chain entanglement of TPU and the reversible covalent crosslink of DFB were formed by the topological reorganization of these two immiscible polymers. As the gelation proceeds, a homogenous structure instead of conventional phase separation is formed. When the mixing ratio of DFB and TPU is 1:1, the tensile strength of the prepared sample reaches 35 MPa, and the elongation at break reaches 110%. At the same time, the composites possess good thermal stability and solvent resistance due to the presence of interlocking polymer networks. Furthermore, these DFB‐TPU composites show excellent shape memory, self‐healing, and closed‐loop recycling properties.

Controllable growth of porous morphology in low dielectric polyimides via thermal-driven spontaneous phase separation

Fabricating porous polymer films with precise morphological control via a conventional phase separation method is challenging. Herein, porous polyimide (PPI) film formation kinetics was thoroughly investigated to understand the underlying phenomena during the thermally induced phase separation. The porous films were prepared using a poly(amic acid) (PAA) solution with a small-molecular phase dispersion agent (i.e., porogen), dibutyl phthalate (DBP), which is miscible with the PAA chains. Using amine-functionalized polyhedral oligomeric silsesquioxane (NH2-POSS) as an additional nucleating agent, sponge-like NH2-POSS end-capped PPI (PPI/NH2-POSSx) films were fabricated with tunable pore size (16.3–76.9 μm) and porosity (42.6–69.4 %). This ensured control over the porous structure of the PPI/NH2-POSSx film, providing desirable low dielectric properties (a minimum of 2 at 1 MHz) in broad frequency and temperature range as well as high thermal stability (Tg = 363–385 °C, T5% = 519–559 °C), and good mechanical strength (17–23 MPa). It was found that the porous structure and physical properties of the PPI/NH2-POSSx films can be readily engineered by tailoring the initial content of a removable porogen and cage silsesquioxane. This work will provide a new perspective on fabricating temperature-resistant low-dielectric porous polymer films with tunable pore sizes via thermal-driven spontaneous phase separation with efficient processability.

Local structure analysis of DyN–ZrN solid solutions

We performed various synchrotron X-ray measurements to extract local and average structures of DyN–ZrN solid solutions. ZrN and AlN have typical phase separation systems, undergoing chemical segregation into ZrN-rich and AlN-rich domains. However, the phase separation of DyN–ZrN has not been investigated. We performed the nanoscale structural analysis to clarify the phase separation in DyN–ZrN by combining X-ray absorption fine structure and high-energy X-ray diffraction. Consequently, discontinuities indicating phase separation were observed in the average and local structures. The results showed that it is differs from the conventional phase separation mechanism caused by the difference in the crystal structure. The DyN–ZrN solid solution has a rock-salt type cubic crystal structure, and there are instabilities such as the chemical order of the metal site and the distribution of the bond length of the nitrogen site. A phase separation has occurred to reduce these structural instabilities.

Disentangling kinetics from thermodynamics in heterogeneous colloidal systems

In Nucleation and Growth, the process by which most heterogeneous systems form, thermodynamics sets the asymptotic boundaries toward which the system must evolve, while kinetics tries to cope with it by imposing the transport rates. In all heterogeneous colloidal systems observed in nature, composition, shape, structure and physical properties result from the trade-off between thermodynamics and kinetics. Here we show, by carefully selecting colloidal systems and controlling phase separation in microfluidic devices, that it becomes possible to disentangle kinetics effects from thermodynamics. Using amyloids and nanocellulose filamentous colloids, we demonstrate that decoupling kinetics from thermodynamics in the phase separation process unveils new physical phenomena, such as orders of magnitude shorter timescales, a wider phase diagram, and structures that are not observable via conventional liquid-liquid phase separation. Our approach enables on-demand fabrication of multicomponent heterogeneous liquid crystals, enhancing their potential, and introducing original fundamental and technological directions in multicomponent structured fluids.

Organic solvent-free polyelectrolyte complex membrane preparation: Effect of monomer mixing ratio and casting solution temperature

The organic solvent-free aqueous phase separation (APS) process is a new and sustainable alternative to the conventional nonsolvent-induced phase separation (NIPS) process. However, low water permeability is a primary concern of such APS membranes. Herein, we introduced casting solution temperature and mixing ratio as two key parameters to improve the performance of poly (sodium 4-styrene sulfonate) (PSS) and branched Polyethylenimine (PEI) complex membrane prepared by pH shift-induced APS process. It was found that PSS-PEI monomer mixing ratios of 1:1.65 and 1:1.70 resulted in nanofiltration membranes with pure water permeability (PWP) of ∼4.5 and ∼8 LMHbar−1. The salt retention tests of these membranes showed higher divalent salt retention than monovalent salt following the order of MgCl2 > MgSO4 > Na2SO4 >NaCl. In comparison, PSS-PEI monomer mixing ratios of 1:1.75 and 1:1.80 led to the formation of ultrafiltration membranes with BSA retention of ∼98% and ∼36%, and PWP of ∼40 and ∼199 LMHbar−1, respectively. The variation of casting solution temperature also showed a significant influence on membrane morphology and performance. The increase in temperature from 25 to 60 °C resulted in ultrafiltration membranes with high BSA retention (>90%) and PWP in the range of ∼53–140 LMHbar−1. This sharp increase in PWP was attributed to the combined effect of the thinner skin layer and larger pore size of the membranes. Overall, this work demonstrated that casting solution temperature and monomer mixing ratio could be used as new tuning parameters for high-performance PSS-PEI membrane fabrication with excellent control over membrane structure and performance.

Reentrant phase separation of a sparse collection of nonreciprocally aligning self-propelled disks.

We study a model of aligning self-propelled disks that nonreciprocally reorient the self-propulsion directions along the interparticle separation and towards the other disks. In the limit of small inertia and large softness, where conventional motility-induced phase separation is absent, we demonstrate that the homogeneous system at a small area fraction phase-separates into clusters and a low-density phase that, eventually, reenters the homogeneous phase with a monotonic increase in alignment strength. The disks inside the clusters move with a finite space-dependent speed, constantly shuttling between clusters through the surrounding low-density homogeneous phase while maintaining the hexatic structure properties within the clusters. The area fraction gradually increases from the periphery towards the center of the clusters with a negligible correlation of the velocity and propulsion direction inside the clusters. The novel collective behavior of reentrant phase separation is found to follow from both the limits of hard disks and extremely small inertia, tending towards the overdamped limit. However, important differences in the structural and dynamical properties are shown in the limit of hard disks and extremely small inertia, as compared to that for soft disks at finite inertia. We show that the cluster phase is associated with an effective temperature for a wide range of values of alignment strength, whereas an effective temperature is associated with the specific range of alignment in the low-density phase. We believe that the reentrant phase behavior in the limit of small area fraction and the remarkable properties of the clusters should be useful in understanding a wide range of physics issues, ranging from clogging and unclogging to information exchange and transport, in biological and synthetic self-propelled systems.

Numerical analysis of phase separation between conductive and insulative materials induced under constant current mode using the extended Cahn–Hilliard equation

In my previous study, on a mixed system of conductive and insulative materials under constant current mode and the constant voltage mode, the extended Cahn–Hilliard equation for a dissipative system was formulated based on Onsager’s variational principle and it was shown that the conductive and insulative materials were phase-separated spatially under the constant current mode. In this study, a detailed analysis of this formula under the constant current mode was carried out by varying the parameter values to elucidate the differences from the conventional phase separation. Unlike conventional phase separation, the phase separation in this study induces as many interfaces as possible and maintains a certain size for the domains. In the domains with a low concentration of the insulative material, the concentrations of insulative and conductive materials are phase-separated to be zero and maximum, respectively.

Unlock the secret of air blowing in developing high strength and superhydrophobic membranes for membrane distillation

Superhydrophobic polyvinylidene fluoride (PVDF) membranes with high mechanical strength are highly desirable for multiple applications. Nevertheless, they can hardly be fabricated using conventional phase separation technologies without post-treatment. In this work, the goal has been achieved by a novel spray-assisted nonsolvent induced phase separation (SANIPS) method with the aid of air blowing. Without any membrane modification, a superhydrophobic membrane (water contact angle: 166.0°, water sliding angle: 20.0°) with excellent mechanical strength (maximum tensile strength: 3.09 MPa, maximum tensile strain: 104.80%, and Young's modulus: 71.29 MPa) can be produced. The resultant membrane exhibits a remarkable liquid entry pressure of 3.25 bar, and a stable direct contact membrane distillation (DCMD) performance over 400 h when being subjected to a hypersaline dye wastewater. The newly developed method has been compared with conventional nonsolvent induced phase separation (NIPS) and vapor induced phase separation (VIPS) methods to reveal its underlying mechanism. We believe this work would shed a new light on large scale production of PVDF membranes with both high strength and superhydrophobicity for clean water production via membrane distillation.

Optically Isotropic Liquid Crystal Mode Templated by Nanoporous Breath Figure Membrane

AbstractIn this study, a printing‐based scalable method is proposed for the higher density of a liquid crystal (LC) nanodroplet structure suitable for the optically isotropic LC mode where the LC nanodomains are accurately templated by a nanoporous breath figure (BF) membrane. The highly porous BF polymeric template structure is reliably obtained by utilizing self‐structured packing effects of the silica nanospheres achieved by doctor blade coating. A nanocomposite film with densely packed silica nanospheres encapsulated by the UV‐crosslinked polymer matrix is made by controlling the blade coating velocity and blade gap conditions. This provides a higher LC fill‐factor condition of the optically isotropic nanodroplet LC (OI‐NDLC) mode with filling the LCs into the nanopores obtained after selective silica etching. The OI‐NDLC structure templated by the nanoporous BF membrane made with the silica nanospheres of 300 nm can effectively resolve the scattering‐induced optical loss and depolarization issues observable in the OI‐NDLC mode prepared by conventional phase separation approaches due to the sufficiently reduced LC droplet size. The structure exhibits a much‐improved light leakage level in the field‐off optically isotropic state, a higher transmittance level as the field‐induced Kerr operation, and resultant improved contrast ratio properties.

Tuning the Pore Structure of Poly(vinylidene fluoride) Membrane for Efficient Oil/Water Separation: A Novel Vapor-Induced Phase Separation Method Based on a Lower Critical Solution Temperature System

The conventional vapor-induced phase separation (VIPS) method for membrane fabrication faces practical challenges related to the long contact time to gaseous nonsolvent and complexity in pore struc...

Model for disordered proteins with strongly sequence-dependent liquid phase behavior.

Phase separation of intrinsically disordered proteins is important for the formation of membraneless organelles or biomolecular condensates, which play key roles in the regulation of biochemical processes within cells. In this work, we investigated the phase separation of different sequences of a coarse-grained model for intrinsically disordered proteins and discovered a surprisingly rich phase behavior. We studied both the fraction of total hydrophobic parts and the distribution of hydrophobic parts. Not surprisingly, sequences with larger hydrophobic fractions showed conventional liquid-liquid phase separation. The location of the critical point was systematically influenced by the terminal beads of the sequence due to changes in interfacial composition and tension. For sequences with lower hydrophobicity, we observed not only conventional liquid-liquid phase separation but also re-entrant phase behavior in which the liquid phase density decreases at lower temperatures. For some sequences, we observed the formation of open phases consisting of aggregates, rather than a normal liquid. These aggregates had overall lower densities than the conventional liquid phases and exhibited complex geometries with large interconnected string-like or membrane-like clusters. Our findings suggest that minor alterations in the ordering of residues may lead to large changes in the phase behavior of the protein, a fact of significant potential relevance for biology.

Storage Stability and Morphology of Latex Modified Bitumen

Bitumen modification is done to enhance the properties of bitumen related to elasticity, temperature susceptibility, softening point etc. This research intends to assess the effects of natural rubber latex (NRL) in liquid form as a bitumen modifier. Conventional tests, temperature susceptibility and phase separation due to hot storage were investigated using two separate mixing speeds of 1200 and 1300 revolution per minutes (rev/min). Morphology due to the addition of NRL has also been explored utilizing Atomic Force Microscopy (AFM). NRL was incorporated into the bitumen by weight of the binder for the modification at three different amounts (i.e. 3%, 5% and 6%). Based on the softening point, penetration value, temperature susceptibility and storage stability the latex-modified asphalt binder were analyzed. Results of the investigation showed that owing to enhancement in viscoelastic properties, the latex-modified asphalt binder will not undergo phase separation during hot temperature storage. Meanwhile, a uniform dispersed network was indicated by the morphological analysis with the presence of three phases of para, peri and cata. It can be deduced from the results obtained that the latex-modified asphalt binders will perform better in terms of softening point, penetration value and susceptibility due to temperature.

Topological rearrangement-derived homogeneous polymer networks capable of reversibly interlocking: From phantom to reality and beyond

The combination of polymers can produce a multicomponent polymeric system, with advanced performance that cannot be achieved by the individual components. An ideal case lies in the creation of all interface materials to maximize the synergistic hybrid effects. Thus far, however, even for the elaborate interpenetrating polymer networks, microheterogeneity is inevitably observed. Herein, we show a conceptual innovative approach to prepare molecular-level interlocking polymer networks by topological reorganization of two immiscible single polymer networks with orthogonal reversible covalent crosslinkages. The conventional phase separation is suppressed as gelation proceeds, and the interlocked networks are further unlocked to a homogenous structure, recovering the original single polymer networks. The resultant interlocking polymer networks show nonlinear improvement in mechanical performance in addition to smart adaptivity like self-healability. An extensible platform technology for bringing in new materials may thus be developed, which is breakthrough in the scope of classic polymer engineering dominated by irreversible covalent chemistry. Furthermore, the long-range interlocked networks themselves are a promising model system for studying soft condensed matter physics.

Surface-concentrated chitosan-doped MIL-100(Fe) nanofiller-containing PVDF composites for enhanced antibacterial activity

Antibacterial properties are a major issue for the membrane-based wastewater treatment since the biofilm on membranes generated by bacterial growth can significantly reduce water flux. Here, the surface-concentrated MIL-100(Fe)/chitosan (MIL100-CS)-embedded polyvinylidene fluoride (PVDF) composite membranes (i.e., PVDF-S/MIL100-CS) were successfully fabricated by the newly developed fabrication method, so-called solvent-assisted nanoparticle embedding (SANE). The SANE method was modified from the conventional nonsolvent-induced phase separation method by the addition of an intermediate step for the selective arrangement of hydrophilic nanofillers on top of the nascent PVDF film. The additional step in the SANE method enabled the surface-selective filler distribution with the open surface of fillers, resulting in the hydrophilic surface. Also, it facilitated to form the sponge-like pore structures mostly due to the dilution effect of additional solvent. The PVDF/MIL100-CS microfiltration (MF) composite membranes acquired by SANE exhibited the higher antibacterial activity and the substantially enhanced biofouling resistance for E. coli cells than those of the pristine PVDF due to the surface-selective arrangement of MIL100-CS fillers which include both hydrophilic and biocidal properties. The live/dead test for antibacterial activities with E. coli cells further confirmed the enhanced suppression of the biofouling resistance in the asymmetric PVDF/MIL100-CS composite membranes relative to that of PVDF. Our current study offers a new platform for fabricating asymmetric MF composite membranes with enhanced antibacterial activity and biofouling resistance.

Suppression of the outwards-dispersing branches in hour-glass magnetic spectra induced by nanoscale phase separation in La2−xSrxCoO4

Here, we reinvestigate the underlying charge and magnetic correlations in ${\mathrm{La}}_{2\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{CoO}}_{4}$ within a combined study of muon spin relaxation ($\ensuremath{\mu}\mathrm{SR}$), x-ray photon correlation spectroscopy, synchrotron radiation single-crystal x-ray diffraction, and neutron-scattering measurements. For ${\mathrm{La}}_{2\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{CoO}}_{4}$ around 1/3 hole-doping, the significant charge correlations that are responsible for the emergence of hour-glass magnetic spectra are found to be slowly fluctuating checkerboard charge ordering (CBCO) correlations with an onset temperature being independent of hole-doping. This reveals a local origin of the CBCO correlations in the rather ionic cobaltates, thus being distinct from the more covalent nickelates. Moreover, we report the observation of a very similar temperature dependence of the intensities of in-plane high- and low-energy excitations within the ${\mathrm{La}}_{2\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{CoO}}_{4}$ hour-glass spectrum. This observation shows that nano phase separation is distinct from conventional phase separation and that there is a coupling between nanometer-sized undoped and hole-doped islands. Based on this, it is possible to propose a microscopic scenario for the suppression of the outwards-dispersing branches in hour-glass magnetic spectra.

Optimization and fouling mechanism of a thermophile submerged MBR (TSMBR) pilot plant for wastewater treatment in a paper mill

The state-of-art is a mesophilic treatment of wastewater in paper mills without reuse due to the high water quality requirements. Thermophilic biological treatment could save a large amount of thermal energy, but the major obstacle of a reuse are the poor sludge settling properties under thermophile conditions, leading to insufficient water quality if conventional gravimetric phase separation is applied. MBR technology is a promising alternative which allows a recirculation of treated water for improving the water and energy footprint. So far, there is only limited experience with thermophilic MBR at the time. In this study, a thermophilic MBR with a submerged membrane (TSMBR) was operated to treat wastewater from a paper mill with a COD concentration of 25–30gL−1. The TSMBR was integrated into the operational process of the paper mill. Research questions were the influence of suspended solids, food to microorganism ratio (F/M ratio), cross-flow-aeration and filtration flux to the fouling of the membrane. Applying the critical flux concept, optimal operating conditions and costs for a future economic full-scale implementation could be derived.Key results are inter alia a sub-critical flux of below 10Lm−2h−1 is recommended for long-time durability of the membrane for minimizing the irreversible fouling and the permeability decrease. A chemical cleaning does not change the critical flux, but improves the permeability of the membrane significantly. The TSMBR suffered from increasing fouling at a cross-flow-aeration of below 0.6m3m−2h−1 and a concentration of suspended solids of above 14gL−1. A stable process and cleaning could only be ensured by a F/M ratio of below 0.4gCODgMLSS−1d−1. Higher values result in an increased cake layer formation and intensive foaming.

Preparation and Characterization of Hydrophilically Modified PVDF Membranes by a Novel Nonsolvent Thermally Induced Phase Separation Method.

In this study, a nonsolvent thermally-induced phase separation (NTIPS) method was first proposed to fabricate hydrophilically-modified poly(vinylidene fluoride) (PVDF) membranes to overcome the drawbacks of conventional thermally-induced phase separation (TIPS) and nonsolvent-induced phase separation (NIPS) methods. Hydrophilically-modified PVDF membranes were successfully prepared by blending in hydrophilic polymer polyvinyl alcohol (PVA) at 140 °C. A series of PVDF/PVA blend membranes was prepared at different total polymer concentrations and blend ratios. The morphological analysis via SEM indicated that the formation mechanism of these hydrophilically-modified membranes was a combined NIPS and TIPS process. As the total polymer concentration increased, the tensile strength of the membranes increased; meanwhile, the membrane pore size, porosity and water flux decreased. With the PVDF/PVA blend ratio increased from 10:0 to 8:2, the membrane pore size and water flux increased. The dynamic water contact angle of these membranes showed that the hydrophilic properties of PVDF/PVA blend membranes were prominently improved. The higher hydrophilicity of the membranes resulted in reduced membrane resistance and, hence, higher permeability. The total resistance Rt of the modified PVDF membranes decreased significantly as the hydrophilicity increased. The irreversible fouling related to pore blocking and adsorption fouling onto the membrane surface was minimal, indicating good antifouling properties.

Electronic and Magnetic Nano Phase Separation in Cobaltates La2−x Sr x CoO4

The single-layer perovskite cobaltates have attracted enormous attention due to the recent observation of hour-glass shaped magnetic excitation spectra which resemble the ones of the famous high-temperature superconducting cuprates. Here, we present an overview of our most recent studies of the spin and charge correlations in floating-zone grown cobaltate single crystals. We find that frustration and a novel kind of electronic and magnetic nano phase separation are intimately connected to the appearance of the hour-glass shaped spin excitation spectra. We also point out the difference between nano phase separation and conventional phase separation.

Synthesis of gelatin nano/submicron particles by binary nonsolvent aided coacervation (BNAC) method

A newly developed modified coacervation method is utilized to synthesize gelatin nano/submicron particles (GN/SPs) as a drug carrier. Binary nonsolvent aided coacervation (BNAC) method is a modified single step coacervation method, which has yielded approximately a threefold lower particle size and higher average yield in terms of weight percentage of around 94% in comparison to the conventional phase separation methods. In this study 0.5% (w/v) gelatin aqueous solution with a binary nonsolvent system of acetone and ethanol was used. Nanoparticle synthesis was optimized with respect to nonsolvent system type and pH. pH7 has resulted a minimum particle size of 55.67 (±43.74) nm in anhydrous medium along with a swollen particle size of 776nm (±38.57) in aqueous medium with a zeta potential of (−16.3±3.51) mV in aqueous medium. Swelling ratio of 13.95 confirms the crosslinked hydrogel nature of the particles. Furthermore, drug loading efficiency of the gelatin particles prepared at 7pH was observed with nitrofurazone as the model drug. Results of drug release study indicate the potential use of GN/SPs as drug loading matrix for wound management such as burn wound management.