Critical Gelation Concentration Research Articles

Rheo-SAXS study of a shear-thinning hydrogel containing clay nanoplatelets

Shear-induced orientation of clay nanoplatelets within a physically cross-linked hydrogel based on ionenes, positively charged polyelectrolytes, is studied here. Small angle X-ray scattering measurements (SAXS) are performed under shear within a Couette cell cylinder (rheo-SAXS). As the SAXS signal is dominated by that of the clay component, we follow the evolution of the orientational distribution of the clay nanoplatelets within the hydrogel as a function of shear. We investigate the effect of the clay volume fraction, polyelectrolyte concentration, clay charge location and clay charge density by screening three different types of clay: Wyoming and Arizona montmorillonites and Idaho beidellite. The orientational field of clay nanoplatelets in the gel is shown to strongly depend on the clay charge location and shear rate, whereas it is independent of the clay volume fraction. Approaching the critical gelation concentration of the polyelectrolyte system, these features change drastically.

Application of various polysaccharide gums to improve gelation and rheological properties of hydroxypropyl starch hydrocolloids

This work aims to develop starch-based low-cost vegetarian soft capsules used for medicine and health products through compounding with different polysaccharide gums. In this work, the phase diagrams, gelation behaviors, rheological properties, and microstructures of hydroxypropyl starch (HPS) blending with various polysaccharide gums, including ι and κ-carrageen (LC and KC), curdlan (CL) and agar (AG) have been investigated. The materials in both solution and hydrogel were systematically characterized in the review of practical processing and application based on the requirements of fabricating soft capsules. The phase diagram was firstly drawn based on critical gel concentration at 30–60 °C; the rheological behaviors of various blending systems were investigated under both oscillatory and dynamical conditions; and the gel microstructures were studied by SEM. The phase diagrams showed that HPS-AG has the lowest critical gel concentration while HPS-CL has the highest one since AG itself has shown the lowest critical gel concentration. The order of both critical gel concentration and viscosity of the HPS-based suspensions is HPS-CL > HPS-KC > HPS-LC > HPS-AG. In contrast, the gel strengths of HPS-based hydrogels are almost opposite to the order of viscosity HPS-AG > HPS-KC > HPS-LC > HPS-CL. Some of the blending systems (HPS-KC and HPS-CL) showed higher viscosity then the summary of the individual material, indicating some polymeric chain intergradation. All the compounding systems showed the porous structure of typical hydrogel, and cell size generally decreased after adding various gums. The hydroxyl bound and network between HPS and gums (carrageen and curdlan) results in higher gel strength of the blending system than that of any single substance. The relationships among the phase diagrams, microstructures, and rheological properties were compared and discussed. The results provide a guideline to design and develop capsules using multi-gums systems based on exploring their individual behaviors.

Phenanthrothiophene-Triazine Star-Shaped Discotic Liquid Crystals: Synthesis, Self-Assembly, and Stimuli-Responsive Fluorescence Properties.

Lipophilic biphenylthiophene- and phenanthrothiophene-triazine compounds, BPTTn and CPTTn, respectively, were prepared by a tandem procedure involving successive Suzuki-Miyaura coupling and Scholl cyclodehydrogenation reactions. These compounds display photoluminescence in solution and in thin film state, solvatochromism with increasing solvent's polarity, as well as acidochromism and metal ion recognition stimuli-responsive fluorescence. Protonation of BPTT10 and CPTT10 by trifluoroacetic acid results in fluorescence quenching, which is reversibly restored once treated with triethylamine (ON-OFF switch). DFT computational studies show that intramolecular charge transfer (ICT) phenomena occurs for both molecules, and reveal that protonation enhances the electron-withdrawing ability of the triazine core and reduces the band gap. This acidochromic behavior was applied to a prototype fluorescent anti-counterfeiting device. They also specifically recognize Fe3+ through coordination, and the recognition mechanism is closely related to the photoinduced electron transfer between Fe3+ and BPTT10/CPTT10. CPTTn self-assemble into columnar rectangular (Colrec) mesophase, which can be modulated by oleic acid via the formation of a hydrogen-bonded supramolecular liquid crystal hexagonal Colhex mesophase. Finally, CPTTn also form organic gels in alkanes at low critical gel concentration (3.0 mg/mL). Therefore, these star-shaped triazine molecules possess many interesting features and thus hold great promises for information processing, liquid crystal semiconductors and organogelators.

Responsive Properties of Bis-urea-based Supramolecular Hydrogels

Physical hydrogels exhibit sol-gel reversibility, which is affected by external stimuli such as variations in pH and temperature. One class of hydrogelators, known as the low-molecular- weight gelators, can form fibrillar networks through noncovalent self-assembly, resulting in the formation of physical gels. This study aims to investigate the pH-responsive properties of bis-urea-based supramolecular hydrogelators. A series of bis-urea compounds containing an aromatic linker and various end groups were synthesized via a one-pot condensation reaction. Gelation of the compounds in water was conducted at pH 2–13, whereby the inversion technique was used to confirm the hydrogel formation. The compound bearing an m-picolyl end group effectively forms gels within the pH 3–12 range. The gelator also exhibits decreasing critical gel concentration with increasing pH, presumably due to the ionizability of the pyridyl groups. Rheological analysis of the gels determined the storage modulus (G’) to be greater than the loss modulus (G”), which indicated the expected solid-like behavior of the hydrogel at low strain. The morphology of the gel obtained by scanning electron microscopy revealed a fibrous aggregated structure. Results obtained from this study may suggest the applicability of bis-urea compounds as pH-sensitive physical hydrogelators.

Ultralight aerogels via supramolecular polymerization of a new chiral perfluoropyridine-based sulfonimidamide organogelator.

Chiral and enantiopure perfluorinated sulfonimidamides act as low-molecular weight gelators at low critical gelation concentration (<1 mg mL-1) via supramolecular polymerization in nonpolar organic solvents and more heterogenic mixtures, such as biodiesel and oil. Freeze-drying of the organogel leads to ultralight aerogel with extremely low density (1 mg mL-1). The gelation is driven by hydrogen bonding resulting in a helical molecular ordering and unique fibre assemblies as confirmed by scanning electron microscopy, CD spectroscopy, and computational modeling of the supramolecular structure.

Mechanically tunable organogels from highly charged polyoxometalate clusters loaded with fluorescent dyes

Inorganic nanowires-based organogel, a class of emerging organogel with convenient preparation, recyclability, and excellent mechanical properties, is in its infancy. Solidifying and functionalizing nanowires-based organogels by designing the gelator structure remains challenging. Here, we fabricate Ca2-P2W16 and Ca2-P2W15M nanowires utilizing highly charged [Ca2P2W16O60]10− and [Ca2P2W15MO60]14−/13− cluster units, respectively, which are then employed for preparing organogels. The mechanical performance and stability of prepared organogels are improved due to the enhanced interactions between nanowires and locked organic molecules. Compressive stress and tensile stress of Ca2-P2W16 nanowires-based organogel reach 34.5 and 29.0 kPa, respectively. The critical gel concentration of Ca2-P2W16 nanowires is as low as 0.28%. Single-molecule force spectroscopy confirms that the connections between cluster units and linkers can regulate the flexibility of nanowires. Furthermore, the incorporation of fluorophores into the organogels adds fluorescence properties. This work reveals the relationships between the microstructures of inorganic gelators and the properties of organogels, guiding the synthesis of high-performance and functional organogels.

Novel Organogels from Mauritia flexuosa L.f and Caryodendron orinocense Karst.: A Topical Alternative.

Organogels have importance for topical applications because they can be used to deliver drugs in a controlled and prolonged fashion. These are materials consisting of a three-dimensional network of organic molecules dispersed in a solvent. Recent studies have demonstrated that the solvent could be replaced by oils from non-conventional biologic sources. There is a diversity of not-explored species in the Amazon that are promising sources of vegetable oils with a promising composition. This study developed an organogel with buriti (Mauritia flexuosa L.f) and cacay (Caryodendron orinocense Karst.) oils, using cetostearyl alcohol as an organogelator due to its compatibility, stability, security, affordability, and it is readily available. The oils were characterized, and the organogels were synthesized by studying their crystal evolution and oil-binding capacity. The microstructure was evaluated with polarized light microscopy, fractal dimension, FTIR spectroscopy, XRD, and thermal and rheological analyses. It was found that the critical gelation concentration was higher for cacay oil as it possessed a higher amount of polyunsaturated triacylglycerols. The crystals of the buriti organogel had a smaller lamellar shape, a greater surface area, and physical and thermal stability; although, it presented a slower crystal evolution due to the low number of minor compounds and a greater number of saturated triacylglycerols. The polar fraction of the organogelators as well as triacylglycerol and minor polar compounds are important in forming crystallization nuclei. The study showed that Amazonian oils in crystallization processes form microstructures with differentiating physicochemical properties.

Synthesis and Thermoreversible Gelation of Coil-Rod Copolymers with a Dendritic Polyethylene Core and Multiple Helical Poly(γ-benzyl-L-glutamate) Arms.

Coil-rod copolymers with a dendritic polyethylene (DPE) core and multiple helical poly(γ-benzyl-L-glutamate) (PBLG) arms (DPE-(PBLG)n) were prepared by palladium-catalyzed copolymerization in tandem with ring-opening polymerization (ROP). Macroinitiator (DPE-(NH2)11) was firstly prepared by the group transformation of DPE-(OH)11 generated from palladium-catalyzed copolymerization of ethylene and acrylate comonomer. Coil-helical DPE-(PBLG)11 copolymers were prepared by ROP of γ-benzyl-L-glutamate-N-carboxyanhydride (BLG-NCA). These DPE-(PBLG)11 copolymers could form thermoreversible gels in toluene solvent, and the dendritic topology of the DPE core increased the critical gelation concentrations. The self-assembled nanostructure of gels was fully characterized by transmission electron microscopy (TEM), atomic force microscopy (AFM), small-angle X-ray scattering (SAXS), and wide-angle X-ray diffraction (WAXD), and the morphology of the fibrous structure was a twisted flat ribbon through a self-assembled nanoribbon mechanism. The self-assembled fibers formed by DPE-(PBLG45)11 are more heterogeneous and ramified than previously observed fibers formed by PBLG homopolymer and block copolymers.

Formation and In Vitro Simulated Digestion Study of Gelatinized Korean Pine Seed Oil Encapsulated with Calcified Wax

Natural waxes have demonstrated exceptional potential as oil gels for saturated and trans fatty acids, but their application has been limited by issues such as temperature sensitivity, lack of stability and durability, and compatibility. In this study, three types of wax (Beeswax (BW), Rice bran wax (RBW), and Carnauba wax (CW)) were combined with calcium hydroxide to produce calcified wax. The calcified Korean pine seed oil gel obtained by heating and stirring with Korean pine seed oil is responsive to temperature and has environmental adaptability. The effects of critical gel concentration, temperature regulation, texture properties, microstructure, oil-holding capacity, and FT-IR on the quality parameters of oil gel were investigated. Additionally, an in vitro digestion model was developed to comprehend the decomposition rate of fat during gel structure digestion and transportation. The results demonstrated a close correlation between the critical gelation concentration and calcium ion content. Furthermore, after calcification, the hardness followed the order BW &gt; CW &gt; RBW. Moreover, there was an approximate 10 °C increase in wax melting point. Conversely, BW:Ca exhibited the lowest oil leakage. The microstructures revealed that the oil gels formed post-wax calcification exhibited similar fractal dimension (Db) values (&lt;7 μm), and the intermolecular forces were characterized by van der Waals forces, which were consistent with those observed in the non-calcified group. In conjunction with the vitro digestion simulation, our findings demonstrated that RBW and CW oil gels gradually released 20%, 35%, and 35% of free fatty acids (FFA) within the initial 30 min of intestinal digestion. Importantly, the FFA release rate was significantly attenuated, thereby providing a foundation for developing wax-based gel processed foods that facilitate gentle energy release benefits for healthy weight management.

Concentration and Solvent-Induced Chiral Tuning by Manipulating Non-Proteinogenic Amino Acids in Glycoconjugate Supra-Scaffolds: Interaction with Protein, and Streptomycin Delivery.

We showed solvent- and concentration-triggered chiral tuning of the fibrous assemblies of two novel glycoconjugates Z-P(Gly)-Glu and Z-F(4-N)-Glu made by chemical attachment of Cbz-protected [short as Z)] non-proteinogenic amino acids L-phenylglycine [short as P(Gly)] and 4-Nitro-L-phenylalanine [short as F(4-N)] with D-glucosamine [short as Glu]. Both biomimetic gelators can form self-healing and shape-persistent gels with a very low critical gelator concentration in water as well as in various organic solvents, indicating they are ambidextrous supergelators. Detailed spectroscopic studies suggested β-sheet secondary structure formation during anisotropic self-aggregation of the gelators which resulted in the formation of hierarchical left-handed helical fibers in acetone with an interlayer spacing of 2.4 nm. After the physical characterization of the gels, serum protein interaction with the gelators was assessed, indicating they may be ideal for biomedical applications. Further, both gelators are benign, non-immunogenic, non-allergenic, and non-toxic in nature, which was confirmed by performing the blood parameters and liver function tests on Wister rats. Streptomycin-loaded hydrogels showed efficacious antibacterial activity in vitro and in vivo as well. Finally, cell attachment and biocompatibility of the hydrogels were demonstrated which opens a newer avenue for promising biomedical and therapeutic applications.

Исследование функционально-технологических свойств сушеного продукта из кожи командорского кальмара «КальмаKS»

The article presents the results of studying the functional and technological properties of the dried product “KalmaKS” made from the skin of Commander squid. Technological properties such as water-retaining capacity (WRC), fat-binding capacity (FBC), fat-emulsifying capacity (FEC), critical gel concentration (CGC), foaming capacity (FC), foam stability (FS), and protein solubility in water have been analyzed as well. The determination of WRC, FBC and FEC has been carried out at different temperatures of the system “KalmaKS – water”: 25 ± 2 and 75 ± 2 °C. It has been ascertained that the product from squid’s skin has a high WRC, reaching 162% at a temperature of 25 °C, it has also been proven that “KalmaKS” binds water significantly better when the temperature rises to 75 °C. The research has shown high values of “KalmaKS’s” FBC (110%); it has been found out that an increase in temperature leads to an increase of this index to a level of 210%. The product made from squid’s skin has a fairly high (44.5%) FEC, slightly increasing with increasing temperature (up to 53%). High indices of CGC (30%) and FS (80%), low values of FC (3%), as well as high indicators of protein solubility (44.5%) have been ascertained. There has been made the conclusion about the possibility of using the product from squid’s skin, “KalmaKS”, in the production of food produce as a structure regulator with water-retaining, fat-binding and gel-forming properties.

Development of Thixotropic Molecular Oleogels Comprising Alkylanilide Gelators by Using a Mixing Strategy.

Molecular oleogels have the potential to be used as materials in healthcare applications. However, their design and synthesis are complex, thus requiring simple and effective methods for their preparation. This paper reports on alkylanilides that are low molecular-weight organogelators, which when appropriately mixed with different alkyl chain lengths could result in the formation of mixed molecular gels that exhibit excellent gel-forming ability and mechanical properties. In addition, the single and mixed molecular organogel systems were found to be applicable as single and mixed molecular oleogel systems capable of gelling oils such as olive oil and squalane. This has been found to be true, especially in molecular oleogel systems consisting of squalane, which is used as solvents in healthcare. The mixed squalene-molecular oleogel systems showed an increase in the critical (minimum) gelation concentration from 1.0 to 0.1 wt.% in the single system and an improvement in the thixotropic behavior recovery time. The thixotropic behavior of the molecular oleogels in the mixed system was quantitatively evaluated through dynamic viscoelasticity measurements; however, it was not observed for the single-system molecular oleogels. Scanning electron microscopy of the xerogels suggested that this behavior is related to the qualitative improvement of the network owing to the refinement of the mesh structure. These mixed molecular oleogels, composed of alkylanilides displaying such thixotropic behavior, could be used as candidates for ointment-base materials in the healthcare field.

Self-Assembly of a Series of Carbazole-Based Vinyl-benzoxazole Derivatives in Gel Phases.

A series of carbazole-based vinyl-benzoxazole derivatives have been synthesized in order to verify whether X-ray diffraction (XRD) simulation can give more information about intermolecular stacking in the gel phase. It was found that their gelation capabilities were strongly dependent on the length of the alkyl chain. The compounds with shorter alkyl chains have lower critical gelation concentrations (CGCs) in nonpolar alkane and alcohols with longer carbon chains. On the other hand, compounds with long alkyl chains presented small CGCs in polar methanol. Powder XRD structure solution gave more information about intermolecular stacking than the traditional way of analyzing diffraction peaks to derive approximate molecular stacking patterns. The results verified that gelators had a similar head-to-tail π-stacking between aromatic groups in gel phases although different slipping angles existed. Moreover, ordered stacking between the alkyl chains was also present.

DBS‐Based Eutectogels: Organized Vessels to Perform the Michael Addition Reaction**

AbstractSupramolecular eutectogels were obtained from the gelation of 1,3 : 2,4‐dibenzylidene‐D‐sorbitol (DBS) in cholinium chloride‐based deep eutectic solvents (DES), differing for the nature of the hydrogen bond donor. Ethylene glycol, diethylene glycol, triethylene glycol, glycerol and urea were tested. Soft materials were fully characterized, determining critical gelation concentration, gel‐sol transition temperatures and mechanical properties. Furthermore, to have information about the organization of the gelator in the tridimensional network, resonance light scattering, circular dichroism and microscopy investigations were performed. Eutectogels were used as organized “vessels” to perform the L‐proline catalyzed Michael addition reaction. The probe reaction was carried out in gel phase and in DES solution. Data collected shed light on the effect that gel microenvironment exerts on the outcome of the reaction. In general, gel phases allowed having comparable or even better results than the ones collected in DES solution, with better results obtained in soft materials with the highest organization, as accounted for by the presence of larger aggregates and the occurrence of stronger intermolecular interactions. In turn, this accounts also for the effect of substrates structure that indicates that better yields could be obtained in the presence of more flexible nucleophile and dienones, having more extended π‐surface.

Comparative pharmacodynamic study delineating the efficacy of amantadine loaded nano-emulsified organogel via intranasal versus transdermal route in rotenone-induced Parkinson's disease rat model

Owing to the dysphagia and gastroparesis in patients concomitant with Parkinson's disease (PD), oral amantadine (AMT) medications are susceptible to poor bioavailability and clinical outcomes. A self-given delivery system controlling the release of AMT is sought to attain high patient compliance and enhanced therapeutic effect. This work focuses on the synthesis of a new potent low-molecular weight organogelator for the formulation of AMT nano-emulsified organogel (AMT-NEO). Among the gelators, the N-palmitoyl l-serine methyl ester (PSM) was selected for its highest gelation power and lowest critical gelation concentration. The D-optimal design was adopted for optimization of formulation variables; A: PSM amount, B: oil amount, and C: oil type. Evaluation of the particle size, zeta potential, polydispersity index, and AMT release was performed for all the formulations. The desirability function of the optimized formula was 0.949. The optimized formula possessed small particle size (162.58 nm), low polydispersity index (0.373), high zeta potential (−22.24 mV) and controlled the AMT release over 12h. A comparative pharmacodynamic study of the intranasal versus the transdermal administration of the optimized AMT-NEO to rats with rotenone-induced PD was performed. The results demonstrated the superiority of the nasal route to neutralize the deleterious effect of rotenone on motor behaviour and the measured biochemical parameters without affecting the histopathological morphology of nasal vestibules or skin layers. Therefore, the intranasal AMT-NEO might offer a shifted paradigm for the controlled release of such polar drug for the management of PD. This will be highly important especially for PD patients suffering from dysphagia.

PH-Sensitive Poly(acrylic acid)-g-poly(L-lysine) Charge-Driven Self-Assembling Hydrogels with 3D-Printability and Self-Healing Properties.

We report the rheological behavior of aqueous solutions of a graft copolymer polyampholyte, constituted of polyacrylic acid (PAA) backbone grafted by Poly(L-lysine) (PAA-b-PLL). The graft copolymer self-assembles in aqueous media, forming a three-dimensional (3D) network through polyelectrolyte complexation of the oppositely charged PAA and PLL segments. Rheological investigations showed that the hydrogel exhibits interesting properties, namely, relatively low critical gel concentration, elastic response with slow dynamics, remarkable extended critical strain to flow, shear responsiveness, injectability, 3D printability and self-healing. Due to the weak nature of the involved polyelectrolyte segments, the hydrogel properties display pH-dependency, and they are affected by the presence of salt. Especially upon varying pH, the PLL secondary structure changes from random coil to α-helix, affecting the crosslinking structural mode and, in turn, the overall network structure as reflected in the rheological properties. Thanks to the biocompatibility of the copolymer constituents and the biodegradability of PLL, the designed gelator seems to exhibit potential for bioapplications.

New Biopharmaceutical Characteristics of In Situ Systems Based on Poloxamer 407.

Thermosensitive systems based on poloxamer 407 are widely used in targeted drug delivery; however, the stability of the phase transition temperature remains insufficiently studied. This article presents the results of a study on the effect of adding polyethylene glycols (PEG) with different molecular weights and some classical gel-forming polymers on the gelation temperature of thermoreversible compositions based on poloxamer 407 in a long-term experiment. The study showed a positive effect of PEG addition with average molecular weights at concentrations of 1.5-2.0%, as well as gelling agents at a concentration below the critical gelation concentration. The proposed rheological test for studying the samples' adhesion can give an indirect forecast of the composition adhesive rate. Based on the conducted studies, three experimental binary systems based on poloxamer 407 were selected, with the addition of HPMC 0.5%, sodium alginate 0.5%, and PEG 1500 1.5%. These systems are the most promising for the further development of in situ targeted drug delivery systems.

Macadamia oil-based oleogels as cocoa butter alternatives: Physical properties, oxidative stability, lipolysis, and application

In this study, macadamia oil-based oleogels were prepared using monoglyceride stearate (MG) as a gelator with a low critical gelation concentration (3.0 wt%). The physical properties of the oleogels were evaluated by polarized light microscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, X-ray diffraction, texture and rheological analysis. And the lipid digestion and oxidative stability of the macadamia oil were determined by pH titration and accelerated oxidation test, respectively. The results showed that the hardness, oil binding capacity, and thermal stability of the oleogels increased with increasing MG concentration, which was attributed to the formation of a network of MG crystals held together by van der Waals interactions and hydrogen bonds. Rheological analysis indicated that all the oleogels exhibited a thermally reversible solid-to-liquid transition and viscoelastic behavior at ambient temperatures. Moreover, the formation of oleogels increased fatty acid release during in vitro lipid digestion and improved the oxidative stability of the macadamia oil. In addition, the potential application of these oleogels as replacements for saturated fats in foods was demonstrated by creating a chocolate product where the cocoa butter was replaced with macadamia oil-based oleogels with a high degree of unsaturation. These results can provide guidance for the preparation of macadamia oil-based oleogels, which may increase their application in foods.

Synthesis, biological activity and assembly of pH-responsive alkyl-substituted naphthalene-type hydrazonotriazole organogelators

Hydrazones have been a significant group of materials with diverse pharmacological and industrial applications, such as treatment of cardiovascular diseases, parasitic infections, and viral disorders, as well as cosmetic and food additives. In this context, we present the synthesis and characterization of novel hydrazonotriazole analogues with different hydrophobic alkoxy units. The synthesized alkyl-substituted naphthalene-type hydrazonotriazoles were able to act as pH-sensitive and thermoreversible organogelators. They were prepared by a straightforward aldol condensation of 2-naphthalaldehyde with different adducts of 1-(5-methyl-1-(4-alkoxyphenyl)-1H-1,2,3-triazol-4-yl)ethan-1-one at room temperature in ethanolic solution and in the presence of sodium hydroxide as a catalytic agent. The provided compounds were exposed to condensation reaction with (2,4-dinitrophenyl)hydrazine in a refluxing acid ethanolic solution. Different spectroscopic methods were utilized to analyze and prove the chemical structures of the naphthalene-type hydrazonotriazoles, inclusing FT-IR, elemental analysis, and NMR spectra. The photophysical properties of the prepared hydrazonotriazoles were reported. The alkyl-substituted naphthalene-type hydrazonotriazole gelators were able to gelate a variety of solvents, displaying a sol–gel reversible response to pH changes together with colorimetric change from yellow to purple. The optimal gelation was monitored for nonyl-substituted hydrazone in a variety of solvents, demonstrating thermal stability up to 58 °C, and critical gelator concentration (CGC) of ∼ 1–11 mM. Several analytical methods were used to inspect the morphological properties of the hydrazonotriazole-based organogelators, displaying self-assembled nanofibers (7–15 nm). Both cytotoxic and antimicrobial activity of the alkyloxy-containing naphthalene-type hydrazonotriazole gelators was investigated.

Macrocycle Self-Assembly Hydrogel for High-Efficient Oil-Water Separation.

Supramolecular hydrogels involved macrocycles have been explored widely in recent years, but it remains challenging to develop hydrogel based on solitary macrocycle with super gelation capability. Here, the construction of lantern[33 ]arene-based hydrogel with low critical gelation concentration (0.05 wt%), which can be used for efficient oil-water separation, is reported. The lantern[33 ]arenes self-assemble into hydrogen-bonded organic nanoribbons, which intertwine into entangled fibers to form hydrogel. This hydrogel which exhibits reversible pH-responsiveness characteristics can be coated on stainless-steel mesh by in situ sol-gel transformation. The resultant mesh exhibits excellent oil-water separation efficiency (>99%) and flux (>6 × 104 L m-2 h-1 ). This lantern[33 ]arene-based hydrogel not only sheds additional light on the gelation mechanisms for supramolecular hydrogels, but also extends the application of macrocycle-based hydrogels as functional interfacial materials.