Solvent-induced Phase Separation Research Articles

Attapulgite-Based Stable Superhydrophobic Coatings for Preventing Rain Attenuation of 5G Radomes.

Superhydrophobic coatings hold immense promise for various applications. However, their practical use is currently hindered by issues such as poor stability, high costs, and complex preparation processes. Here, we present the preparation of cost-effective and stable superhydrophobic coatings through fluorination of natural attapulgite (F-ATP) nanorods and subsequent solvent-induced phase separation of a silicone-modified polyester adhesive (SMPA) with the F-ATP nanorods dispersed in it. Phase separation of the F-ATP/SMPA system forms a uniform suspension of microaggregates, which can be easily utilized for preparing superhydrophobic coatings via spray coating. The coatings have a low-surface-energy hierarchical micro/nanostructure due to phase separation of SMPA and adhesion of F-ATP to it. Moreover, the effects of the solvent composition (i.e., phase separation degree of SMPA) and the SMPA/F-ATP mass ratio on the morphology, superhydrophobicity, and stability of the coatings were investigated. After systematic optimization, the coatings exhibit excellent static and dynamic superhydrophobicity as well as high mechanical, chemical, thermal, and UV aging stability. Finally, the coatings were applied to the 5G radome surface and showed good rain attenuation prevention performance. Thus, we are confident that the superhydrophobic coatings have great application potential due to their advantages of outstanding performance, straightforward preparation procedures, cost-effectiveness, etc.

Large scalable, anti-ultraviolet, strong cellulose film with well-defined dual-pores for longtime daytime radiative cooling

Passive daytime radiative cooling technology, which reflects sunlight and emits thermal radiation simultaneously, shows great potential in releasing global warming and energy consumption. Particularly, cellulosic cooling materials, with the advantages of high infrared emissivity, eco-friendly, and easy processing, have gained great attention. However, the poor solar reflectance and the poor durability related to UV and mechanical properties still limited its broad applications. In this work, we developed a novel cellulose composite film (CCF) with a well-defined, hierarchical micro/nanostructure via a rational solvent-induced phase separation technology for efficient and longtime daytime radiative cooling. TiO2@PT synthesized via facile ball milling process was used to serve as a dual functional modifier, which can improve the optical, mechanical properties, and anti-UV function of the cellulose-based daytime radiative cooler. Benefiting from the hierarchical dual pores, formed tough interface, and assembled anti-UV functional network, the as-prepared CCF displayed ultrahigh solar reflectance of 97.6 % and enhanced Young's modulus and tensile strength increase by 13 and 4.4 times, respectively. Most importantly, the solar reflectance of CCF is maintained constant after continuous UV tests for 720 h. The work provides a general strategy to simultaneously enhance both the mechanical stability and the UV durability of polymer-based PDRC materials toward large-scale applications.

Two different routes to prepare porous biodegradable composite membranes containing nanoclay

AbstractThe method employed for membrane preparation and nanoparticle incorporation in membrane systems can affect their properties. This work aims to compare the better strategy to obtain membranes from the preparation of PBAT [Poly(butylene adipate co‐terephthalate)] containing nanoclay Cloisite® 20A (C20A) (0, 0.5, and 1 wt.%) by combined Evaporation/Non‐solvent Induced Phase Separation (EIPS/NIPS) or dip coating methods. The SEM, TGA, contact angle measurements, FTIR, XRD, mechanical testing, and cost analysis characterized EIPS/NIPS to dip coating membranes. EIPS/NIPS membranes had smaller pores (0.3–0.5 μm), with a more homogeneous pore diameter distribution due to C20A nanoclay insertion. PBAT/0.5% C20AEIPS/NIPS was the more hydrophilic membrane (37°) with better mechanical properties proven by statistical analysis. The cost analysis showed that EIPS/NIPS membranes production cost per square meter (m2) was lower (US$ 73.4–73.8) than dip coating (US$ 89.0–99.2). The EIPS/NIPS method was the most economically and statistically advantageous, and its properties can favor future applications for PTEs removal in aqueous media.

Stable and impalement-resistant superamphiphobic coatings enabled by phase-separated adhesive for anti-adhesion of viscous liquids with low surface tension

Superamphiphobic coatings have great potential in various fields but surfer from weak mechanical stability, low impalement resistance and poor repellency to viscous liquids with low surface tension. Here, we report stable and impalement-resistant superamphiphobic coatings enabled by phase-separated adhesive for anti-adhesion of viscous liquids with low surface tension. By fluorination of silica (F-silica) nanoparticles and solvent induced phase separation of an adhesive, a homogeneous suspension was obtained, which could be readily used for preparing superamphiphobic coatings via spray-coating. The effects of phase separation degree and adhesive/F-silica mass ratio on superamphiphobicity, impalement resistance and mechanical stability of the coatings were studied. The coatings have a hierachical micro-/nanostructure and numerous perfluorodecyl groups on the surface. Thus, the coatings show excellent static and dynamic superamphiphobicity, e.g., high contact angles, low sliding angles, high maximum release height, short solid-liquid contact time and large bouncing height for various liquids with high viscosity and low surface tension. The coatings also show excellent mechanical stability, good chemical and temperature stability. Furthermore, the coatings are applicable onto diverse substrates and could be easily scaled-up.

Amino−functionalized Fe(III)−Based MOF for the high−efficiency extraction and ultrasensitive colorimetric detection of tetracycline

In order to achieve the simultaneous extraction and detection of tetracycline (TC) in milk, the amino−functionalized Fe−based metal−organic frameworks (NH2−MIL−88B) was synthesized via a solvothermal method with Fe3+ and 2−aminoterephthalic acid (NH2−BDC) as precursor. Thanks to the unique structure of NH2−MIL−88B, it could be used to highly effective extract of TC in milk. More interestedly, the introduced –NH2 could react with –OH from TC by a hydrogen-bonding interaction to cause the electronic interactions that enhances the peroxidase−like activity of NH2−MIL−88B, which result in the enhancement of Fenton reaction by the transfer of the electron between TC and NH2−MIL−88B. Under the optimal testing conditions, the linear absorbance response is well correlated with the TC concentration range of 50–1000 nM, which can reach a low LOD of 46.75 nM. Besides, the sensor exhibits excellent selectivity to TC, and the proposed strategy can also be applied to milk with good recovery (83.33–107.00%). Finally, the NH2−MIL−88B and cellulose acetate (CA) are combined to form nanozyme hybrid membranes through the non−solvent induced phase separation method, which can be used to prepare point−of−care testing (POCT) for rapid and in−situ detection of TC.

Controlled formation of highly porous polylactic acid‑calcium phosphate granules with defined structure

Synthetic bone repair materials are becoming increasingly popular in tissue engineering as a replacement for autografts and human/animal-based bone grafts. The biomedical application requires precise control over the material composition and structure, as well as over the size of granulate used for filling the bone defects, as the pore size and interconnectivity affect the regeneration process. This paper proposes a process of alloplastic and biodegradable polylactic acid/β-tricalcium phosphate granulates preparation and its parameters described. Using solvent-induced phase separation technique, porous spheres have been obtained in various sizes and morphologies. The design of the experiment's approach generated an experimental plan for further statistical modeling using the resulting data. The statistical modeling approach to the data from conducting a designed set of experiments allowed analysis of the influence of process parameters on the properties of the resulting granules. We confirmed that the content of β-tricalcium phosphate plays the most significant role in the size distribution of prepared granulate. The shape of the particles becomes less spherical with higher phosphate concentration in the emulsion. The proposed technique allows preparing porous granulates in the 0.2–1.8 mm diameter range, where granules' mean diameter and sphericity are tunable with polymer and phosphate concentrations. The granulate created a potentially implantable scaffold for resected bone regeneration, as cytotoxicity tests assured the material is non-cytotoxic in vitro, and human mesenchymal stem cells have been cultured on the surface of granulates. Results from cell cultures seeded on the Resomer LR 706S granulates were the most promising.

Scalable preparation of high-strength hierarchically porous carbon beads with bicontinuous macroporous network by solvent induced phase separation technique for NOx removal

The potential of hierarchically porous carbons is drastically limited by their intrinsic fragility, tedious preparation, high cost, and poor processability. Here we develop a novel solvent-induced phase separation technique for fast and continuous preparation of hierarchically macro-/microporous carbon beads (MMCBs). The as-prepared MMCBs show spherical shape with millimeter size, which give the carbons many value-added physical properties such as regular geometry, good mechanical properties, low dust, and good flowability. The MMCBs have a high BET surface area of 1099 m 2 g −1 , and percolating macroporous superstructure with axial-oriented macrovoid channel and sponge-like bicontinuous network issued from solvent-induced macrophase separation and microphase separation, respectively. In addition, the MMCBs have a high nitrogen doing of 4–5 wt% originated from their nitrogen-rich polyacrylonitrile precursor. The MMCBs could directly sever as the metal-free carbon catalysts for room-temperature oxidation of NO to NO 2 with over 80% conversion, and the urea-loaded MMCBs could use for selective catalytic reduction of NO to N 2 with long-time NO x removal. This convenient synthesis to porous carbons with the engineered morphology and percolating macropores has great potential in practical applications where both rapid mass transport and high surface areas are required. Scalable preparation of high-strength porous carbon beads with hierarchically macroporous network by solvent induced phase separation for NOx removal. • Macro/microporous carbon beads with bicontinuous macroporous network were prepared. • The MMCBs have highly spherical shape and millimeter size. • The MMCBs have high strength, high wear resistance, low dust, and good flowability. • The MMCBs could sever as the metal-free catalysts for room-temperature oxidation of NO to NO 2 . • The urea-loaded MMCBs could use for selective catalytic reduction of NO to N 2 .

Liquid crystal droplet design by using pseudopeptidic bottlebrush polymer additives.

Liquid crystal (LC) droplets are promising candidates for sensing applications due to their high sensitivity to surface anchoring changes, resulting in readily detectable optical effects. Herein, we have designed and synthesized amino acid-based bottlebrush polymers and investigated their impact on LC director configurations in the droplets. The pseudopeptidic bottlebrush polymers with an aromatic (phenyl) and aliphatic appendages are synthesized using ring-opening metathesis polymerization (ROMP). Polymer dispersed liquid crystal (PDLC) samples are prepared by employing pseudopeptidic bottlebrush polymers and 4-cyano-4'-pentylbiphenyl (5CB) LC via solvent-induced phase separation (SIPS) technique. Due to π-π stacking, the phenyl group favours radial configuration, whereas the repulsion between 5CB and aliphatic groups induces molecular alignment leading to bipolar droplet arrangement. The impact of various pendant groups attached to the polymer on the prepared PDLC sample's surface characteristics and free energy components is illustrated. The sensing capability of 5CB dispersed in pseudopeptidic bottlebrush polymers for various pH solutions is investigated using polarizing optical microscopy (POM). The PDLC samples are moderately permeable to water and sensitive to different pH solutions. The results demonstrate a simplified and straightforward approach for preparing LC-based biosensors and chemical sensors.

Simultaneous removal of phosphorus and soluble organic pollutants by a novel organic/inorganic nanocomposite membrane via Zr(OH)4 in-situ decoration

BackgroundExcessive phosphorus is the primary nutrient causing water eutrophication. It is of major practical significance to remove pollutants by membrane filtration while adsorbing phosphorus. MethodsIn this study, Zr(OH)4-PVDF organic/inorganic nanocomposite membrane was formed by in-situ formation of Zr(OH)4 nanoparticles from ZrOCl2 precursor by sodium hydroxide solution during non solvent induced phase separation process. Significant FindingsThe Zr doping in the in-situ grown films is more uniform, and phosphate could be selectively and quickly adsorbed after the decoration of zirconium, and good adsorption capacity was realized as high as 58.67 mg g−1. At the same time, this Zr(OH)4 decorated composite membrane had excellent filtration performance, which could effectively remove organic pollutants, such as dyes. This novel organic/inorganic nanocomposite membrane with Zr(OH)4 nanoparticles in-situ decoration exhibited high adsorption capacity, fast adsorption kinetics and good repeatability, and some water soluble pollutants such as dyes could be filtered successfully. All these could provide a promising new strategy for the in-situ fabrication of organic/inorganic nanocomposite membrane and a new direction for the design of efficient phosphorus removal filter membrane with excellent adsorption performance.

From Chlorinated Solvents to Branched Polyethylene: Solvent‐Induced Phase Separation for the Greener Processing of Semiconducting Polymers

AbstractDespite having favorable optoelectronic and thermomechanical properties, the wide application of semiconducting polymers still suffers from limitations, particularly with regards to their processing in solution which necessitates toxic chlorinated solvents due to their intrinsic low solubility in common organic solvents. This work presents a novel greener approach to the fabrication of organic electronics without the use of toxic chlorinated solvents. Low‐molecular‐weight non‐toxic branched polyethylene (BPE) is used as a solvent to process diketopyrrolopyrrole‐based semiconducting polymers, then the solvent‐induced phase separation (SIPS) technique is adopted to produce films of semiconducting polymers from solution for the fabrication of organic field‐effect transistors (OFETs). The films of semiconducting polymers prepared from BPE using SIPS show a more porous granular morphology with preferential edge‐on crystalline orientation compared to the semiconducting polymer film processed from chloroform. OFETs based on the semiconducting films processed from BPE show similar device characteristics to those prepared from chloroform without thermal annealing, confirming the efficiency and suitability of BPE to replace traditional chlorinated solvents for green organic electronics. This new greener processing approach for semiconducting polymers is potentially compatible with different printing techniques and is particularly promising for the preparation of porous semiconducting layers and the fabrication of OFET‐based electronics.

ZIF-8 in-situ growth on amidoximerized polyacrylonitrile beads for uranium sequestration in wastewater and seawater

With the vigorous development of nuclear power and the shortage of terrestrial uranium resources, the extraction uranium from seawater is extremely attractive for human development. Herein, we first report ZIF-8 in-situ growth on amidoximerized polyacrylonitrile (PAO) porous materials. The porous material is a small sphere with certain mechanical strength synthesized by solvent-induced phase separation method. Because ZIF-8 nanocrystals are well-formed and evenly distributed within the PAO beads, ZIF-8/PAO has a high specific surface area (386 m2 g-1) and rich pore structure. At adsorption experiment, the highest adsorption capacity of ZIF-8/PAO reached 803 mg g-1 at pH = 4. Furthermore, competitive adsorption experiment and simulated seawater test was studied. The selectivity for uranium was excellent (Kd = 1.7 × 105 mL g-1) and uranium adsorption rate reached 99% at 3 ug L-1. XPS analysis shows that U(VI) is chelated by imidazole-N atoms and amidoxime groups in ZIF-8/PAO. Therefore, ZIF-8/PAO can be considered a highly promising adsorbent for uranium extraction from wastewater and seawater.

Removal of arsenic, nitrate and fluoride by PEES/Nano- Silver Hybrid Membranes

In this present work, we have investigated the arsenic, fluoride and nitrate removal by the poly (ether-ether-sulfone) (PEES)/nano-silver hybrid membranes effectively prepared by the non solvent induced phase separation. The prepared membranes were characterized by thermal and mechanical properties to investigate the influence of nano-silver on the final properties of the membranes. Hence, our experimental study is based on arsenic (III) and arsenic (V) rejection studies attempted at different pH. The results of this study revealed the As (V) removal by NF with a high rejection of 99.98% compared to As (III). Fluoride and nitrate studies were carried out at neutral pH and it showed more than 80% rejection. Based on this investigation, it was concluded that the PEES/nano-silver membranes were effectively applicable to remove hazardous metal ions.

Fabrication of AgNPs@Bowl-shaped structure with excellent antibacterial activity

Bacterial infection has been attracted significant attention as it became an austere menace to public health systems. In this work, a novel thin-wall bowl-shaped particles (BSPs) were prepared by the solvent-induced phase separation method. Firstly, the copolymerization of methacrylic acid (MAA) and methyl methacrylate (MMA) were employed to synthesize amphipathic poly(methacrylic acid-co-methyl methacrylate) (PMA) chains in a solvent of EtOH/H2O. Secondly, hydrophobic hard monomer and hydrophilic soft monomer were introduced into the amphiphilic PMA solution to polymerize and assemble within polyvinylpyrrolidone (PVP) aqueous solution, which afforded a thin-wall BSPs. Its micromorphology and composition were characterized by SEM, FT-IR, TGA and DLS. Furthermore, Ag nanoparticles (AgNPs) were loaded to the surface of thin-wall BSPs through in situ reduction of silver ion (Ag+). Notably, the obtained Ag@BSPs exhibited excellent antibacterial properties against E. coli and S. aureus, which has enormous application prospects in the prevention and treatment of bacterial infections.

Carbon nano-fibers/ribbons with meso/macro pores structures for supercapacitor

The solubility of polyacrylonitrile (PAN) in nitromethane/water mixture was calculated by Hansen solubility parameter, and observed using optical microscope. The results showed PAN electrospinning precursor can be obtained in nitromethane and water mixed solvent with some volume ratio. PAN porous electrospun fibers/ribbons were obtained via solvent induced phase separation methods during electrospinning process. Then, PAN electrospun fibers/ribbons were carbonized and activated, the carbon nano-fibers/ribbons with meso/macro pores structure can be prepared. Furthermore, the supercapacitors were fabricated by porous PAN electrospun fibers/ribbons and carbon nano-fibers/ribbons as separator and electrode, respectively. The relationship between electrochemical performance and pore structure parameter of nano-fibers/ribbons was investigated in ionic liquid electrolyte, the results showed nano-ribbons with a high proportion meso/macro pores structure, which achieved high specific capacity (244.1 F·g−1), high charging/discharging efficiency (99.8%) and low internal resistance (0.52 Ω).

High-performance sodium-ion storage: multi-channel carbon nanofiber freestanding anode contrived via ingenious solvent-induced phase separation

Solvent-induced phase separation was introduced to produce multi-channel carbon nanofibers, delivering excellent sodium-ion storage capability and rate performance.

Incorporation of a silicon-based polymer to PEG-DA templated hydrogel scaffolds for bioactivity and osteoinductivity

A scaffold that is inherently bioactive, osteoinductive and osteoconductive may guide mesenchymal stem cells (MSCs) to regenerate bone tissue in the absence of exogenous growth factors. Previously, we established that hydrogel scaffolds formed by crosslinking methacrylated star poly(dimethylsiloxane) (PDMSstar-MA) with diacrylated poly(ethylene glycol) (PEG-DA) promote bone bonding by induction of hydroxyapatite formation (“bioactive”) and promote MSC lineage progression toward osteoblast-like fate (“osteoinductive”). Herein, we have combined solvent induced phase separation (SIPS) with a fused salt template to create PDMSstar-PEG hydrogel scaffolds with controlled PDMSstar-MA distribution as well as interconnected macropores of a tunable size to allow for subsequent cell seeding and neotissue infiltration (“osteoconductive”). Scaffolds were prepared with PDMSstar-MA of two number average molecular weights (Mns) (2k and 7k) with varying PDMSstar-MA:PEG-DA ratios and template salt sizes. The distribution of PDMSstar-MA within the hydrogels was examined as well as pore size, percent interconnectivity, dynamic and static moduli, hydration, degradation and in vitro bioactivity (i.e. mineralization when exposed to simulated body fluid, SBF). Finally, cell culture with seeded human bone marrow-derived MSCs (hBMSCs) was used to confirm non-cytotoxicity and characterize osteoinductivity. Tunable, interconnected macropores were achieved by utilization of a fused salt template of a specified salt size during fabrication. Distribution of PDMSstar-MA within the PEG-DA matrix improved for the lower Mn and contributed to differences in specific material properties (e.g. local modulus) and cellular response. However, all templated SIPS PDMSstar-PEG hydrogels were confirmed to be bioactive, non-cytotoxic and displayed PDMSstar-MA dose-dependent osteogenesis. Statement of SignificanceA tissue engineering scaffold that can inherently guide mesenchymal stem cells (MSCs) to regenerate bone tissue without growth factors would be a more cost-effective and safe strategy for bone repair. Typically, glass/ceramic fillers are utilized to achieve this through their ability to induce hydroxyapatite formation (“bioactive”) and promote MSC differentiation to an osteoblast-like fate (“osteoinductive”). Herein, we have fabricated an interconnected, macroporous PEG-DA hydrogel scaffold that utilizes PDMSstar-MA as a bioactive and osteoinductive scaffold component. We were able to show that these PDMSstar-PEG hydrogels maintain several key material characteristics for bone repair. Further, bioactivity and osteoinductivity were simultaneously achieved in human bone marrow-derived MSC culture, representing a notable achievement for an exclusively material-based strategy.

Preparation and Characterization of High Flux Polypropylene Microfiltration Membrane via Non-Solvent Induced Phase Separation

Abstract High flux polypropylene (PP) membranes were prepared by using non solvent induced phase separation method. Polyethylene glycol (PEG) was used as an additive. The highest flux was obtains by PP membrane prepared with 5 % wt. PEG, i.e. 1230 Lm-2h-1, while the PP membrane without addition of PEG was 813 Lm-2h-1. The IR Spectra confirmed the presence of PEG in PP membranes. Visualization of membrane morphology demonstrated uniform structure for the PP membrane prepared using addition of PEG 5 %wt. with the pore size within the range 0.3-0.4 µm.

Facile fabrication of superporous and biocompatible hydrogel scaffolds for artificial corneal periphery.

Biocompatible and highly porous network hydrogel scaffolds were fabricated for the development of artificial cornea (AC) periphery/skirt that could be used to enhance the long-term retention of the implants. In this study, a series of hydrogel scaffolds for this application was fabricated from the photo-polymerization of a mixture of poly(ethylene glycol) (PEG)- and poloxamer (P407)-based macromer solutions in dichloromethane in which solvent-induced phase separation (SIPS) arose to form scaffolds with macroporous structure and high water content. The overall porosity ranging from 20% to 75% and open/closed pore structure of the hydrogel scaffolds could be finely tuned by varying the ratio of P407/PEG in the macromer solution and solvent type. The total porosity and open-cell structure of the macropores in the synthesized hydrogel scaffolds affected the swelling behavior, dynamic properties such as the storage moduli of the hydrogels as well as their degradation rates. Based on the subcutaneous implantation in rats, superporous hydrogel scaffolds induced the formation of thinner fibrous capsules around the implants and showed less inflammatory reaction, suggesting that the hydrogel scaffolds made from SIPS exhibited good cytocompatibility. The combined results of swelling ratio, porosity, physical strength and subcutaneous implant tests indicated that the superporous hydrogels with porosity >50% showed potentials to be used for cornea periphery application.

Evidences of the Effect of GO and rGO in PCL Membranes on the Differentiation and Maturation of Human Neural Progenitor Cells.

The effect of doping graphene oxide (GO) and reduced graphene oxide (rGO) into poly(ε-caprolactone) (PCL) membranes prepared by solvent induced phase separation is evaluated in terms of nanomaterial distribution and compatibility with neural stem cell growth and functional differentiation. Raman spectra analyses demonstrate the homogeneous distribution of GO on the membrane surface while rGO concentration increases gradually toward the center of the membrane thickness. This behavior is associated with electrostatic repulsion that PCL exerted toward the polar GO and its affinity for the non-polar rGO. In vitro cell studies using human induced pluripotent cell derived neural progenitor cells (NPCs) show that rGO increases marker expression of NPCs differentiation with respect to GO (significantly to tissue culture plate (TCP)). Moreover, the distinctive nanomaterials distribution defines the cell-to-nanomaterial interaction on the PCL membranes: GO nanomaterials on the membrane surface favor higher number of active matured neurons, while PCL/rGO membranes present cells with significantly higher magnitude of neural activity compared to TCP and PCL/GO despite there being no direct contact of rGO with the cells on the membrane surface. Overall, this work evidences the important role of rGO electrical properties on the stimulation of neural cell electro-activity on PCL membrane scaffolds.

Phenothiazine based nanocrystals with enhanced solid state emission

The paper focuses on the preparation of phenothiazine based nanoparticles, both in liquid and solid states, by reprecipitation in water and solvent induced phase separation respectively. Polymethylmethacrylate was used as an inert matrix and polyfluorene as a luminescent matrix. The morphological features of the nanoparticles were investigated by dynamic light scattering, and SEM, AFM and POM microscopy, which revealed their supramolecular ordering as nanocrystals. Their photophysical behaviour was monitored by UV–vis and photoluminescence spectroscopy. The nanocrystals emitted green light, with higher efficiency compared to the bulk crystals, reaching an absolute quantum yield of 35% in water, 45% in polymethylmethacrylate, and 39% in polyfluorene.