F127 Content Research Articles

Biocompatible, 3D Printable Magnetic Soft Actuators – Ink Formulation, Rheological Characterization and Hydrogel Actuator Prototypes

Abstract3D printable inks for the preparation of magnetic hydrogel actuators are difficult to formulate because magnetic nanoparticles tend to aggregate without stabilization through other ink components. At the same time, such inks need to be shear‐thinning and recover their high viscosity state sufficiently fast to be suitable for the printing process. Here, the use of chitosan as dispersing agent for Fe2O3 nanoparticles is reported. Combined with Pluronic F127 as a rheology modifier and acrylamide as the base monomer, thermoresponsive and shear‐thinning magnetic inks containing well‐dispersed particles are obtained. The ink viscosity is tuned over two orders of magnitude by varying the chitosan and Pluronics F127 content. 3D‐printed shapes with good shape fidelity are obtained at a print bed temperature of 50 °C, where aggregation of the Pluoronics F127 micelles occurs. This leads to a fast recovery of the high viscosity state of the material, so that the printed shape can then be locked in by UV cross‐linking. This treatment yielded magneto‐responsive prototypes which are promising for soft robotics applications. Thanks to the simplicity of the ink formulation, it is easily transferable also to nonspecialist laboratories, and the concept is potentially applicable also to other types of nanoparticles.

Transcellular Transport Behavior of the Intact Polymeric Mixed Micelles with Different Polymeric Ratios.

In order to better promote the application of the polymeric mixed micelles (PMMs) in oral delivery, in addition to focusing on the improvement of micellar structural stability, it is necessary to obtain the absorption characteristics of the intact micellar particles. In this work, the transport behavior across Caco-2 cells of FS/PMMs composed of Pluronic F127 and Solutol HS15 was tracked by encapsulating an environment-responsive probe into the particles. The specific property of the probe is the water-initiated aggregation-caused quenching (ACQ) ability, by which integral particles can be identified accurately. The influence of polymeric ratios (FS) on the transcellular behavior of FS/PMMs was explored and the single pass intestinal perfusion experiment was used to further illustrate it. Moreover, pharmacokinetics parameters were detected to analyze the relationship among FS ratios, transport behavior, and pharmacokinetic parameters. FS ratios were found to hardly affect the endocytosis pathways and intracellular itinerary of FS/PMMs, but do affect the proportion of each path. FS/PMMs with high HS15 content, namely System-I, were found to primarily undergo receptor-mediated endocytosis pathway and be less susceptible to lysosomal degradation, which would lead to more absorption and higher Cmax and AUC than drug suspension. In contrast, despite System-II with high F127 content cannot contribute to drug plasma concentration, it can prolong the in vivo retention time. These findings provided evidence for the role of polymeric ratios in modulating the transcellular absorption and pharmacokinetic parameters of the drug-loaded PMMs, and would be a step forward in helping PMMs' design to enhance oral drug delivery.

Metalized hierarchical porous poly-melamine-formaldehyde membrane for continuous-flow reduction of 4-nitrophenol

BackgroundPorous organic polymers (POPs) are excellent candidates for supporting and stabilizing metal nanocatalysts. The preparation of POPs monolithic membranes as carrier materials for continuous flow catalytic reactors is of significant industrial value. MethodsIn this work, monolithic poly-melamine-formaldehyde (ah-PMF) gel-filled membranes were prepared by filling high internal phase emulsions containing melamine and paraformaldehyde into nickel membranes with specific shapes. After in situ loading of palladium nanoparticles (Pd NPs) in ah-PMF, the composite membranes were used for the catalytic reduction of p-nitrophenol (4-NP) to p-aminophenol (4-AP) under both static and continuous flow conditions. Significant findingsThe ah-PMF with high specific surface area and advanced hierarchical porous structure can be obtained by regulating the F127 feed, which is beneficial to improving the catalytic efficiency. The results showed that the Pd@ah-PMF composite membrane had better catalytic activity when the F127 content was 35%, especially in the continuous flow catalytic process, with 99% conversion of 10 mg/L 4-NP in 21 min. In addition, the Pd@ah-PMF showed good recyclability. This work provides a strategy for the design of carrier materials for continuous flow reactors.

In-situ construction of water capture layer through reaction enhanced surface segregation for pervaporation desalination

Membranes with dense water capture layer and porous support layer hold great promise for achieving high flux in pervaporation desalination. Such membranes are usually fabricated by two-step methods, which often suffer from poor interfacial compatibility and membrane pore blockage. Herein, we fabricated a hetero-structured membrane with a dense water capture layer and a porous support layer in one step by reaction enhanced surface segregation (RESS) method. During the fabrication of polyether sulfone (PES) support layer via non-solvent induced phase separation (NIPS) process, the amphiphilic copolymer F127 in the casting solution and tannic acid (TA) in the coagulation bath migrated and reacted rapidly to each other, in-situ forming a TA-F127 water capture layer. The composition and structure of the water capture layer were tuned by controlling F127 content, TA concentration and reaction time. The optimal flux of 49.04 kg m−2 h−1 with the rejection of 99.99% was realized when treating 3.5 wt% NaCl solution at 70 °C. The membrane showed great adaptability for treating different concentrations of saline water. This study may provide a facile and scalable method for fabricating hetero-structured membranes toward efficient desalination.

Highly antifouling porous EVAL/F127 blend membranes with hierarchical surface structures

Membrane fouling is widely acknowledged as the major hindrance to the efficient separation of oil-water emulsions. Superhydrophilic EVAL/F127 porous membranes with micron-submicron hierarchical structure were prepared via micro-molding assisted immersion precipitation (PSμm process). The micron-scale concave-convex structure was constructed by the micro-molding process with 1000 mesh sandpaper, and then the sub-micron structure of the surface was modulated by F127. With the combination of optimized hierarchical structure and F127 hydrophilic modifier, EVAL/F127 porous membrane is superhydrophilic (water contact angle less than 10°) and strongly anti-fouling. ATR-FTIR, SEM, AFM, water contact angle (WCA), pure water flux, porosity and equilibrium water content were used to characterize the textural and properties of EVAL porous membranes. The separation performance and antifouling properties of the membranes were evaluated using oil-in-water emulsions as fouling agents. When the F127 content was 10%, the EVAL/F127 blended porous membrane not only performed well in retention performance (95.3% retention), but also had high flux recovery (91.6%) after hydrodynamic cleaning. Thus, the combined strategy based on hierarchical structure and hydrophilic modification provides a facile solution for the preparation of antifouling membranes.

Modification of polysulfone ultrafiltration membranes using block copolymer Pluronic F127

The effect of the addition of triblock copolymer polyethylene glycol (PEG)–polypropylene glycol (PPG)–polyethylene glycol (PEG) (Pluronic F127) and polyethylene glycol (PEG-4000, Mn = 4000 g mol−1) to the polysulfone (PSF) casting solution on the membrane structure and performance was studied. The phase state, viscosity and turbidity of PSF solutions in N,N-dimethylacetamide (DMAc) with the addition of block copolymer Pluronic F127 were investigated. It was found that 18–22 wt.% PSF solutions in DMAc with Pluronic F127 content ≥ 5 wt.% feature a lower critical solution temperature (LCST). Membrane structure was investigated using scanning electron and atomic force microcopies. It was revealed that average pore size and pore amount on the surface of the membrane selective layer increase and pore size distribution becomes wider with an increase in Pluronic F127 content in the casting solution. It was found that the average surface roughness parameters of the membrane selective layer for PSF/Pluronic F127 membranes significantly exceed those for PSF/PEG-4000 membranes. It was shown that the increase in the membrane flux and the decrease in polyvinylpyrrolidone (PVP K-30, Mn = 40,000 g mol−1) rejection are a result of the addition of both Pluronic F127 and PEG-4000 into the casting solution. It was revealed that PSF/Pluronic F127 membranes are characterized by higher pressure resistance in ultrafiltration process, a lower total flux decrease during ultrafiltration of bovine serum albumin solutions. The antifouling performance of PSF/Pluronic F127 membranes was found to exceed significantly the antifouling performance of PSF/PEG-4000 membranes.

In situ pocket-type microcarrier (PMc) as a therapeutic composite: Regeneration of cartilage with stem cells, genes, and drugs

We prepared pocket-type micro-carriers (PMc) with pores larger than 30 μm for use in cell delivery by adding 40 mg pluronic F-127 copolymers (F-127) to biodegradable PLGA dissolved in dichloromethane solution. The controlling the size of the pockets in this way facilitates the adhesion of cells by regulating the size of the pockets according to the cells having various sizes. The size of PMc pores could be controlled within a range of 2 to 30 μm by varying the F-127 content. The ratio of F-127 to DOPA-bPEI was most appropriate at 1: 1, and the pocket size at 10 mg/ml of F-127 was appropriate for adhering 20–30 μm stem cells. F-127 containing SOX9 pDNA, in combination with DOPA-polyethylene–coated gold nanoparticles and dexamethasone loaded in PMcs, promoted cartilage differentiation. Gold nanoparticles complex and dexamethasone (DEX) loaded in PMcs were identified by micro-CT imaging and fluorescence imaging, respectively. By captured in pore generated on/in microspheres, the stem cells were safe and stable for use in delivery, both in vitro and in an animal model. Thus, microsphere pores can safely capture stem cells, and at the same time provide a microenvironment in which the captured stem cells can differentiate into chondrocytes.

Modification of polysulfone membranes using triblock copolymer of polyethylene glycol and polypropylene glycol

The phase state, viscosity and optical properties of polysulfone (PSF) solutions in N,N-dimethylacetamide (DMAc) with the addition of block copolymer Pluronic F127 and polyethylene glycol (PEG-4000, M n = 4000 g-mol -1 ) were studied. Additives are both pore-forming and hydrophilizing agents. It was found that 18-22 % PSF solutions in DMAc with the Pluronic F127 content t ≥5 wt. % feature a lower critical solution temperature (LCST). Mixed matrix PSF/Pluronic F127 and PSF/PEG membranes were obtained by the phase inversion technique and the comparative studies of their structure and performance were carried out. It was found that the average surface roughness parameters of PSF/Pluronic F127 membranes significantly exceed those of PSF/PEG membranes. The presence of the both additives in the casting solution leads to the effective hydrophilization of the membrane selective layer. It was shown that the increase in the membrane flux and the decrease in the polyvinylpyrrolidone (K-30, M n = 40000 g-mol -1 ) rejection coefficient are a result of adding both Pluronic F127 and PEG-4000 to the casting solution. It was shown that PSF/Pluronic F127 membranes are characterized by higher shrinkage resistance and a lower total flux decrease during ultrafiltration of bovine serum albumin solutions. It was found that the antifouling performance of PSF/Pluronic F127 membranes significantly exceeds that of PSF/PEG membranes.

Hexamine-induced co-assembly to N-doped ferromagnetic mesoporous carbon nanospheres for dye adsorption

Hexamine-induced co-assembly route has been employed to prepare N-doped ferromagnetic mesoporous carbon nanospheres (Fe-NMCNs) and successfully solve the issue concerning the fast reaction rate of carbon precursor, wherein F127 acts not only as porogen but also as an interface stabilizing agent, and hexamine is utilized as a substitute to release formaldehyde gradually. Luckily, the particle size of the thus-produced Fe-NMCNs can be well tuned by changing the F127 content. More importantly, the Fe-NMCNs-0.4 presents high specific surface area (435.8 cm2/g), large pore volume (0.42 cm3/g) and good mesoporous structure (ca. 3.2 nm). Moreover, the incorporation of nitrogen and iron imparts it with surface wettability, magnetic property and thermal stability for efficiently removing water pollutants such as dye molecule, especially for basic fuchsin.

Influence of γ-Lactones on Monolinolein/Water Bulk and Emulsified Mesophases

The emulsification of two flavor compounds of the γ-lactone type with monolinolein liquid crystalline submicron particles is reported. The stabilization is ensured by the copolymer F127. γ-Nonalactone can be loaded in bicontinuous cubic monolinolein particles at a larger level (up to 20 wt %) than γ-decalactone (less than 15 wt %). The phase behavior of the ternary monolinolein/water/γ-nonalactone system was studied. The large γ-nonalactone content solubilized into cubosomes was corroborated by the observation of a wide cubic V2 range in the ternary phase diagram. Surprisingly, no inverted hexagonal phase was found in the system. On the contrary, the incorporation of γ-decalactone in the lipid particles gave rise to a dispersion of inverted hexagonal phase, which corresponds to a classical behavior of an oily additive. We finally determined the internal phase of particles including 10 wt % of γ-nonalactone upon increasing the F127 content. We thus found that γ-nonalactone restricts very significantly the interaction of the emulsifier with the cubosomes' interior.

Electrospinning of Polycaprolactone/Pluronic F127 dissolved in glacial acetic acid: fibrous scaffolds fabrication, characterization and in vitro evaluation

sThe Polycaprolactone (PCL) fibrous scaffolds in nano to micro scale have been considered as excellent templates for cell culture and tissue growth. The hydrophobic nature of the PCL, however, yields low initial cell seeding density, heterogeneous cell spreading and slow cell growth rate. Therefore, in this study the surface hydrophilic fibrous scaffolds were directly fabricated by the electrospinning of PCL solutions with small quantities (0.5–5%) of Pluronic F127 (PEO100-PPO65-PEO100) dissolved in benign solvent of glacial acetic acid. The clear and miscible solutions were achieved by controlling the proper F127 content in the blend solutions. The continuous and smooth fibers with average diameters from 0.71 to 1.43 μm made up the fibrous scaffolds in non-woven mode. Then the water wetting angle of the scaffolds could be adjusted from 126° to 0° by varying F127 content owing to its hydrophilic PEO chains presented on surface the blended fibers. Finally, it was demonstrated that the blended fibrous scaffolds with the F127 content less than 1% exhibited better cell attachment, proliferation and spreading performance than those of pure PCL scaffolds.

Systemic mRNA Delivery to the Lungs by Functional Polyester-based Carriers.

Messenger RNA (mRNA) has recently come into focus as an emerging therapeutic class with great potential for protein replacement therapy, cancer immunotherapy, regenerative medicine, vaccines, and gene editing. However, the lack of effective and safe delivery methods impedes the broad application of mRNA-based therapeutics. We report a robust approach to develop efficient polymeric delivery carriers for mRNA. Lead polyesters were identified by in vitro screening of a 480-member combinatorially modified poly(trimethylolpropane allyl ether-co-suberoyl chloride) library for the delivery of luciferase encoding mRNA (Luc mRNA) to IGROV1 cells. The formulation of mRNA polyplex nanoparticles (NPs) with Pluronic F127 decreased the surface charge. Although this improved the stability of mRNA nanoparticles, the delivery potency decreased with increased F127 content. Thus, we determined that NP stabilization with 5% F127 could balance the protective effects and delivery potency. 5% F127 formulated PE4K-A17-0.33C12 mRNA NPs enabled luciferase expression predominantly in the lungs after intravenous injection into mice. The efficient mRNA delivery specifically to lungs by degradable carriers suggests the potential for the treatment of pulmonary diseases.

Interfacial Property of Amphiphilic Copolymer Blending PVDF UF Membrane and Protein Anti-fouling

The phase transformation kinetic process of amphiphilic copolymer polyoxyethylene/polyoxypropylene/polyoxyethylene[PEO-PPO-PEO(F127)] blending polyvinylidene fluoride (PVDF) casting solution in an aqueous gel bath was investigated. The influences of F127 content on the PEO enrichment rate of PVDF membrane surface, membrane morphology and structural parameters were investigated by a total reflection fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscope (SEM), atomic force microscopy (AFM) and other analytical techniques. F127/PVDF blending membrane fouling behavior of bovine serum albumin (BSA) was evaluated by the static adsorption capacity, normalized filtration decay rate and membrane fouling resistance model. The results showed that the membrane delayed phase separation process increased, the membrane surface, internal pore size and porosity increased and the surface roughness increased with increasing F127 addition, and the increment of PEO enrichment rate on the membrane surface became stable when the F127 content reached 15%. F127 blending membranes with F127 contents ranging from 15% to 25% had a higher flux and BSA rejection, lower static adsorption capacity, slower flux decay rate, lower irreversible fouling index and smaller pore blocking resistance and cake layer resistance distribution coefficient, which showed a good anti-fouling property.

Phenolic resin/PEO-PPO block copolymer composite materials as phase change materials (PCM) for latent heat thermal energy storage (LHTES)

Many block copolymers can be used in the soft-template synthesis procedures of OMC (ordered mesoporous carbon). Some of the most common are block copolymers composed of PEO [poly (ethylene oxide)] and PPO [poly(propylene oxide)], like the triblock copolymer Pluronic F127 (PEO106PPO70PEO106). DSC analysis of Pluronic F127 shows endothermic and exothermic peaks (at 54 and 30°C) due to the melting and crystallization of the PEO blocks. This indicates that this commercially available block copolymer could be used as a phase change material (PCM).Nanostructured polymer blends like the phenolic resin/PEO-PPO block copolymer composite materials prepared using some soft-template synthesis procedures of OMC could be useful as a solid-solid PCMs if the crystallization of the PEO blocks of the block copolymer is possible within the material.DSC analysis of particles of a phenolic resin/F127 composite material (material P9) prepared using one soft-template synthesis procedure of OMC in solution in basic media (thermal treatment of an alkaline (pH around 9) aqueous solution of F127 and a phenol-formaldehyde resin, followed by centrifugation) shows no evidence of an endothermic or exothermic process. A reduction of the pH of the phenol-formaldehyde resin aqueous solution (from about 9 to 8.5) before the thermal treatment has an effect in the phase separation, that in this case leads to the formation of two layers; a polymer rich phase in the bottom of the reactor and above a layer composed mainly by water. Thermal treatment of the polymer rich phase at 100°C for 24h yields a solid composite material (material P8.5). DSC analysis shows an endothermic peak (35°C) in every cycle, attributable to the fusion of PEO crystalline domains. This indicates that the crystallization of the PEO blocks is possible in this material; but there is not an obvious exothermic peak.The material P8.5 has a higher F127 content (around 60%; estimated by TGA) than the material P9 (around 40%); this indicates that in these composite materials the final block copolymer content has an effect on the crystallization of the PEO blocks.Other synthesis procedures of OMC like EISA (evaporation induced self-assembly) provide a better control of some characteristics, like the block copolymer content. Materials with a high F127 content (60% m/m) were prepared by EISA (controlled evaporation of the solvent of an ethanolic solution of F127 and a phenol-formaldehyde resin, followed by a thermopolymerization process at 100°C for 24h). The DSC analysis shows an endothermic peak (38°C) and an exothermic peak at a low temperature (–20°C).These results indicate that the synthesis procedures of OMC using a phenolic resin and a PEO block copolymer could be a suitable alternative for the production of solid-solid PCMs.

A Novel Route to Prepare Titanium Doped Mesoporous Carbon

A series of titanium doped ordered mesoporous carbons (Ti-OMCs) were prepared by employing titanium modified resol as source for the first time. The effect of titanium content and F127 content on the microstructure of Ti-OMCs was investigated by X-ray diffraction (XRD), N2 sorption isothermal and Transmission electron microscopy (TEM). The results showed that regularity of products decreased with the increase of titanium content. A mesophase transformation from 2-D hexagonal (P6mm) to body-centered cubic () structure can be achieved by decreasing F127 content.

Triblock polymer mediated synthesis of Ir–Sn oxide electrocatalysts for oxygen evolution reaction

Over the past several decades, tremendous effort has been put into developing cost-effective, highly active and durable electrocatalysts for oxygen evolution reaction (OER) in the proton exchange membrane water electrolyzer. This report explores an advanced and effective “soft” material-assistant method to fabricate Ir0.6Sn0.4O2 electrocatalysts with a 0.6/0.4 ratio of Ir/Sn in precursors. Adopting a series of characterization methods, the collective results suggest that the surfactant-material F127 content, as an important factor, can efficiently control the formation of Ir–Sn oxides with varying surface properties and morphologies, such as the grainy and rod-shaped structures. Associating with the half-cell and single electrolyzer, it is affirmed that the optimal ratio of (Ir + Sn)/F127 is 100 for the preparation of S100-Ir0.6Sn0.4O2 with obviously enhanced activity and sufficient durability under the electrolysis circumstances. The lowest cell voltages obtained at 80 °C are 1.631 V at 1000 mA cm−2, and 1.820 V at 2000 mA cm−2, when applying S100-Ir0.6Sn0.4O2 OER catalyst and Ti-material diffusion layer on the anode side and Nafion® 115 membrane. Furthermore, the noble-metal Ir loading in the same cell decreases to 0.77 mg cm−2. These results highlight that Ir–Sn oxide synthesized by the soft-material method is a promising OER electrocatalyst.

Application of orthogonal experimental design in synthesis of mesoporous bioactive glass

An orthogonal experimental design method combining with quantitive analysis of small-angle X-ray scattering (SAXS) pattern was applied to optimize the synthesis of bioactive glasses with highly ordered mesoporous structure (MBGs). The quantitive analysis of SAXS pattern allows a quantified evaluation of the ordering of the mesoporous structure, which makes it possible to tailoring the mesoporous structure of the MBGs with complex component by a traditional orthogonal experimental design method. The number of trials for preparing MBGs can be greatly reduced and the primary factors affecting the formation of mesoporous structure and the properties of MBGs can be easily found out by this orthogonal experimental design method. MBGs containing SiO2, CaO, Fe2O3 were prepared as an example to present the way to obtain optimized ordered mesoporous structure. It confirmed that Fe2O3 was the primary factor influencing the mesoporous structure of the MBGs. The ordering of the mesopores increased in the first and then decreased with the increase of F127 content.

Synthesis and Photocatalytic Activity of Titania Monoliths Prepared with Controlled Macro- and Mesopore Structure

Herein, we report a one-pot synthesis of crack-free titania monoliths with hierarchical macro-mesoporosity and crystalline anatase walls. Bimodal macroporosity is created through the polymer-induced phase separation of poly(furfuryl alcohol). The cationic polymerization of furfuryl alcohol is performed in situ and subsequently the polymer becomes immiscible with the aqueous phase, which includes titanic acid. Addition of template, Pluronic F127, increases the mesopore volume and diameter of the resulting titania, as the poly(ethylene glycol) block interacts with the titania precursor, leading to assisted assembly of the metal oxide framework. The hydrophobic poly(propylene glycol) micelle core could itself be swollen with monomeric and oligomeric furfuryl alcohol, allowing for mesopores as large as 18 nm. Variations in synthesis parameters affect porosity; for instance furfuryl alcohol content changes the size and texture of the macropores, water content changes the grain size of the titania and Pluronic F127 content changes the size and volume of the mesopore. Morphological manipulation improves the photocatalytic degradation of methylene blue. Light can penetrate several millimeters into the porous monolith, giving these materials possible application in commercial devices.

Characterization of PLGA based composite nerve guidance conduits: Effect of F127 content on modulus over time in simulated physiological conditions

PLGA/pluronic F127 based nerve guidance conduits (NGCs) for peripheral nerve regeneration offer excellent potential for clinical use. To date, little emphasis has been directed towards the effect of pluronic F127 on their subsequent mechanical properties as a function of degradation time or the physiological environment. This report was designed to redress the balance. This study synthesised 5 groups of 20wt% PLGA NGCs with varied additions of pluronic F127 (range 0–5wt%) to obtain Young's Moduli (E) in the range of 7–107MPa, depending on degradation conditions and pluronic F127 content.

Rheological properties of polyvinyl butyral/Pluronic F127/PEG200 blend systems

The influence of temperature and mass fraction of Pluonic F127 on the rheological properties of polyvinyl butyric (PVB)/Pluronic F127/polyethylene glycol (PEG) 200 blend systems was investigated by a rotational rheometer with parallel plates. The results show that the blend systems approach homogeneous state at 140, 150 and 160 °C while the rheological properties of the blend systems significantly deviate from the homogeneous systems at 120 °C. Shear thinning behavior is observed for all the blend systems at different temperatures and is enhanced by increasing Pluronic F127 content. The complex viscosity, storage modulus, loss modulus, zero-shear activation energy and flow recovery of the blend systems increase with the increase of Pluronic F127 content. There is a crossing point for the loss modulus and the storage modulus of each sample at high frequency, which is called specified frequency (SF). The loss modulus is larger than the storage modulus when the frequency is less than the SF, and when frequency is more than SF, the loss modulus is smaller than the storage modulus.