Self-assembly In Aqueous Solution Research Articles

Emergence and Rearrangement of Dynamic Supramolecular Aggregates Visualized by Interferometric Scattering Microscopy.

Studying dynamic self-assembling systems in their native environment is essential for understanding the mechanisms of self-assembly and thereby exerting full control over these processes. Traditional ensemble-based analysis methods often struggle to reveal critical features of the self-assembly that occur at the single particle level. Here, we describe a label-free single-particle assay to visualize real-time self-assembly in aqueous solutions by interferometric scattering microscopy. We demonstrate how the assay can be applied to biphasic reactions yielding micellar or vesicular aggregates, detecting the onset of aggregate formation, quantifying the kinetics at the single particle level, and distinguishing sigmoidal and exponential growth of aggregate populations. Furthermore, we can follow the evolution in aggregate size in real time, visualizing the nucleation stages of the self-assembly processes and record phenomena such as incorporation of oily components into the micelle or vesicle lumen.

Синтетические меротерпеноиды на основе терпеновых спиртов: синтез, самосборка и мембранотропные свойства

Currently, targeted drug delivery is of great interest in the field of medicine. The study of compounds capable of permeating cell membranes is a major problem in this area. The synthesis of pharmacologically active compounds includes the formation of structures with various combinations of pharmacophore fragments and properties. Amphiphilic compounds tend to exhibit membranotropic activity. From this point of view, the modification of natural products, especially terpenoids, is of particular interest. Terpenoid structures are used as membrane anchors in the development of modulators for membrane-integrated proteins or structures for creating nanocontainers. In this paper we synthesized a number of water-soluble amphiphilic meroterpenoids containing a charged pyridinium fragment on the basis of acyclic terpene alcohols. Residue of terpene alcohols – geraniol (monoterpenol), farnesol (sesquiterpenol), and phytol (diterpenol) – were used as the hydrophobic part of the amphiphilic structure. Linear acyclic alcohols are commercially available reagents and have a structure similar to that of polyprenols in archaeal lipids, which made it possible to obtain synthetic lipid-like meroterpenoids capable of self-assembly in aqueous solutions. The charged pyridinium fragment, which is included in numerous natural compounds, was of interest as a polar component. This meroterpenoids are synthetic analogs of archaeal lipids. It was shown that the studied meroterpenoids form nanosized aggregates in aqueous solutions by the method of dynamic light scattering and the Doppler microelectrophoresis method. Turbidimetric titration on model dipalmitoylphosphatidylcholine vesicles revealed that the synthesized compounds are embedded into the bilayer membrane without destroying it. Self-assembled aggregates of synthesized compounds in water can find application for drug delivery – in the creation of nanocontainers containing membrane anchors capable of interacting with the outer surface of the cell (lipid membrane).

Photosensitive Supramolecular Micelle-Mediated Cellular Uptake of Anticancer Drugs Enhances the Efficiency of Chemotherapy.

The development of stimuli-responsive supramolecular micelles with high drug-loading contents that specifically induce significant levels of apoptosis in cancer cells remains challenging. Herein, we report photosensitive uracil-functionalized supramolecular micelles that spontaneously form via self-assembly in aqueous solution, exhibit sensitive photo-responsive behavior, and effectively encapsulate anticancer drugs at high drug-loading contents. Cellular uptake analysis and double-staining flow cytometric assays confirmed the presence of photo-dimerized uracil groups within the irradiated micelles remarkably enhanced endocytic uptake of the micelles by cancer cells and subsequently led to higher levels of apoptotic cell death, and thus improved the therapeutic effect in vitro. Thus, photo-dimerized uracil-functionalized supramolecular micelles may potentially represent an intelligent nanovehicle to improve the safety, efficacy, and applicability of cancer chemotherapy, and could also enable the development of nucleobase-based supramolecular micelles for multifunctional biomaterials and novel biomedical applications.

A facile strategy to construct fluorescent pH-sensitive drug delivery vehicle

Aliphatic polyesters have led to significant advancements in drug delivery systems spanning decades owing to their biocompatibility and biodegradability. A series of pH-sensitive aliphatic polyesters were synthesized by facile enzymatic polymerization, which could be post-modified by click chemistry to form multifunctional graft copolymers. Typically, the hydrophilic methoxy polyethylene glycol (mPEG) and fluorescent coumarin were grafted onto the polyester backbone to constitute a multifunctional amphipathic graft copolymer, serving as a trackable pH-responsive drug delivery vehicle. This amphipathic graft copolymer could encapsulate hydrophobic doxorubicin (DOX) via self-assembly in aqueous solutions and performed superior controlled drug release. And the in vitro cellular uptake and cytotoxicity results showed the feasibility of this system for drug delivery application. Collectively, this copolymer offers a potential route of constructing controlled drug delivery system.

Synthesis of Amphiphilic Diblock Copolymer and Study of Their Self-assembly in Aqueous Solution

This paper describes the synthesis of novel amphiphilic diblock copolymer composed of polystyrene (PS) as the hydrophobic block and Poly(N-[3-(dimethylamino)propyl] methacrylamide) (PDMAPMA) as hydrophilic block by reverse-mode iodine transfer controlled radical polymerization (RITP). Initially, homopolymer based on activated monomers (styrene) was synthesized by RITP. Thereafter, amphiphilic diblock copolymer was synthesized. The diblock copolymer obtained was characterized by spectroscopic methods: FTIR, 1H NMR, 13C NMR, Energy-dispersive X-ray spectroscopy (EDX) to analyze the elemental composition. Their thermal behaviour was investigated by thermogravimetric analysis (TGA). Study of the self-organization in aqueous phase of the amphiphilic copolymer revealed that formation of micelles for concentrations was higher than critical aggregation concentration (CAC) which their values were determined by tensiometry. The self-assembly behaviors of this copolymer was studied in aqueous solution at different concentrations, PH and temperatures using Dynamic light scattering (DLS).

Syntheses and crystal structures of two uranyl peroxide nanoclusters with a diphosphonate linker ligand

Two uranyl peroxide nanoclusters with etidronate ligand [L = (PO3)2C(OH)CH3]4−] have been prepared via self-assembly in aqueous solutions and structurally characterized. K40[(UO2)20(O2)20L10]·nH2O (1) has a barrel-shaped structure constructed by linking two pentagonal and one decagonal uranyl peroxide rings with ten etidronate ligands. K38[(UO2)26(O2)33L6]·nH2O (2) has a round top and flat bottom structure constructed by linking a double connected pentagonal uranyl peroxide unit (U8) and a dome-shaped uranyl peroxide unit (U18) with six etidronate ligands. The presence of uranyl ion, peroxide and etidronate ligands has been confirmed by Raman spectroscopy and the role of K+ counter ions on the formation of such clusters has been examined.

β-Chitin Nanofibril Self-Assembly in Aqueous Environments.

Chitin is one of the most studied biopolymers but the understanding of how it assembles from molecules to microfibers is still limited. Organisms are able to assemble chitin with precise control over polymorphism, texture, and final morphology. The produced hierarchical structure leads to materials with outstanding mechanical properties. In this study, the self-assembly in aqueous solutions of β-chitin nanofibrils, as far as possible similar to their native state, is investigated. These nanofibrils increase their tendency to self-assemble in fibers, up to millimetric length and ≈10 μm thickness, with the pH increasing from 3 to 8, forming loosely organized bundles as observed using cryo-transmission electron microscopy. The knowledge from this study contributes to the understanding of the self-assembly process that follows chitin once extruded from cells in living organisms. Moreover, it describes a model system which can be used to investigate how other biomolecules can affect the self-assembly of chitin nanofibrils.

A novel FK506 loaded nanomicelles consisting of amino-terminated poly(ethylene glycol)-block-poly(D,L)-lactic acid and hydroxypropyl methylcellulose for ocular drug delivery

FK506 (tacrolimus) is an effective immunosuppressant, but its poor water solubility and low bioavailability impose barriers to ocular drug delivery. The nanomicelles (NMs) formulations comprised of amino-terminated poly(ethylene glycol-block-poly(D,L)-lactic acid) (NH2-PEG-b-PLA) and hydroxypropyl methylcellulose (HPMC) were developed to increase the penetration of hydrophobic drugs in the eye and enhance the drug bioavailability for ocular disorder therapy. Spherical FK506/NH2-PEG-b-PLA/HPMC NMs with mean diameter of 101.4 ± 1.3 nm were prepared by solvent-evaporation-induced self-assembly in aqueous solution. The NMs that sufficiently solubilized FK506 were evaluated in terms of stability, drug loading, encapsulation efficiency, surface tension, cellular cytotoxicity and in vitro release, and the results revealed the NMs were suitable for intraocular drug delivery. Compared with the 0.05% FK506 suspension drops, the in vitro permeation amount of FK506 from NMs exhibited significant increase. Besides, the higher concentration and longer retention of FK506 in ocular tissue were also confirmed in vivo. Furthermore, the FK506/NH2-PEG-b-PLA/HPMC NMs obviously inhibited the allograft rejection after corneal transplantation in rats. In conclusion, FK506/NH2-PEG-b-PLA/HPMC NMs formulations as a promising ocular drug delivery system would be able to improve the bioavailability and efficacy of FK506 in anti-allograft rejection.

Macrocyclic Compounds as Amphiphile Adaptors

In recent years, modulating amphiphilic assembly by macrocyclic receptors has been emerging as a fantastic topic. As we know, amphiphiles possess ability of selfassembly in aqueous solution due to their unique structures, resulting in important biological functions and various applications in our daily life and industry. Among methods to modulate their assembly behavior, using macrocyclic compounds as amphiphile adaptors owns advantages of convenience and efficiency. Preorganized structures and cavities of macrocyclic compounds enable them the ability of efficiently interacting with amphiphiles in different manners. These additional interactions alter amphiphilic assembly. In this review, we would like to provide a systemic summary of why and how macrocyclic compounds could behave as amphiphile adaptors. For this objective, we introduce related works from the viewpoint of intermolecular interaction. In general, addition of interactions which decrease electrostatic reputation of amphiphiles could promote amphiphilic assembly, and vice versa. Addition of interactions which prevent hydrophobic interaction could inhibit amphiphilc assembly. On the other hand, complexation of macromolecular compounds and amphiphiles could cause steric hindrance, which is unfavorable for assembly. We also take several classical amphiphiles as examples to clarify how different macrocyclic compounds adapt amphiphile assembly. Keywords: Macrocyclic compounds, amphiphile, assembly, supramolecular chemistry, calixarene, cyclodextrin, cucurbituril.

Self-Assembly of Europium-Containing Polyoxometalates/Tetra-n-alkyl Ammonium with Enhanced Emission for Cu2+ Detection.

Lanthanide-containing polyoxometalates (POMs) can be used to detect various materials, but their luminescence in water has suffered enormous limitations due to the strong fluorescence quenching. Herein, to resolve this problem, three-dimensional nanoparticles built by mixed Weakley-type europium-containing POMs (Na9[EuW10O36]·32H2O, abbreviated to EuW10) and tetra-n-alkyl ammonium (TA) with enhanced fluorescent properties have been designed in aqueous solution using an ionic self-assembly (ISA) technique, which is mainly driven by the electrostatic interaction between EuW10 and TA. The morphology and fluorescent properties of the system as well as some influencing factors (alkyl chain length, amino group, and inorganic salt concentration) were systematically investigated. The results indicated that the fluorescent intensity of EuW10/tetramethylammonium bromide (TMAB) composite increased about 14 times, whereas the extent of increase of fluorescence for EuW10/tetraethylammonium bromide (TEAB) and EuW10/tetrabutylammonium bromide (TMAB) composites gradually decrease due to the bulkier steric hindrance of the longer alkyl chain. Besides, the luminescence of EuW10/TMAB nanoparticles is pH responsive, and the reversibility of their structures and luminescence can be realized upon the addition of NaOH/HCl. Moreover, the EuW10/TMAB system also shows great fluorescence-sensing behavior, which could detect Cu2+ with a detection limit of 0.15 μM. Our work provides a facile construction strategy for a functional fluorescent complex via POMs-based supramolecular self-assembly in aqueous solution, which will be further used in biomarkers and sensors.

Self-Assembly and Chiral Recognition of Chiral Cationic Gemini Surfactants.

Chiral cationic gemini surfactants 1,4-bis(dodecyl- N, N-dimethylammonium bromide)-2,3-butanediol (12-4(OH)2-12) including racemate, mesomer, and two enantiomers were synthesized and their self-assembly in aqueous solution has been comparatively investigated by tensiometry, conductometry, 1H NMR, small-angle neutron scattering, cryogenic transmission electron microscopy, and cryogenic scanning electron microscopy. The chirality at spacer induces different self-assembly behaviors due to the hydrogen-bonding interaction between the hydroxyl groups at the chiral centers. The stereochemistry of the spacer has little effect on the release of the counterions from the surfactant headgroups and on the molecular packing at the air-water interface. The critical micelle concentration (CMC) decreases in the order of racemate > enantiomer > mesomer. Above the CMC, the aggregates of enantiomers transit from small spherical micelles to rodlike and wormlike micelles with increasing concentration, whereas the mesomer and racemate aggregates transform from spherical micelles to rodlike micelles and platelet-like aggregates. The differences may be because the mesomer and racemate molecules mainly form intermolecular hydrogen bonds between the -OH groups, but the enantiomer molecules dominantly form intramolecular hydrogen bonds. Furthermore, it was found that the chiral micelles formed by the enantiomers exhibit enantioselection ability for bilirubin (BR) enantiomers. The recognition capability can be adjusted by the micellar structure, i.e., the rodlike micelles are better than either small spherical micelles or wormlike micelles, which might possess different chiral cavities, controlling BR shape and location. These results demonstrate that the aggregates of chiral gemini surfactants can be used to mimic the chiral recognition in biological membrane.

Adsorbents for Organic Dyes Based on PDMAEMA/POSS Hybrid Material via Thiol-Michael Addition Reaction

The organic/inorganic hybrid material of poly[2-(dimethyl amino)-ethyl methacrylate]/polyhedral oligomeric silsesquioxane (POSS–PDMAEMA) was synthesized via a thiol-Michael addition reaction. The structures of POSS–PDMAEMA and its self-assembly in aqueous solution were confirmed by 1H-NMR, TEM, DLS, UV–Vis and fluorescence spectrum. In aqueous solutions, POSS–PDMAEMA could self-assemble into micelles and its critical micelle concentration was 12.4 mg/L. POSS–PDMAEMA micelles can adsorb dyes efficiently, it could adsorb methyl red at a concentration of 10–100 mg/L and dithizone at a concentration of 20–100 mg/L, and could remove 98% methyl red and 90% dithizone within 30 s. Due to the good temperature and pH responsiveness, POSS–PDMAEMA micelles could release organic dye absorbed into the organic solution again when the solution was heated to 40 °C or pH value of the solution was adjusted to 4.0. It suggested that POSS–PDMAEMA can be utilized as an interesting “smart” materials for absorption of organic dyes.

Sequential intracellular release of water-soluble cargos from Shell-crosslinked polymersomes

Polymer vesicles, i.e. polymersomes (PS), present unique nanostructures with an interior aqueous core that can encapsulate multiple independent cargos concurrently. However, the sequential release of such co-loaded actives remains a challenge. Here, we report the rational design and synthesis of oxidation-responsive shell-crosslinked PS with capability for the controlled, sequential release of encapsulated hydrophilic molecules and hydrogels. Amphiphilic brush block copolymers poly(oligo(ethylene glycol) methyl ether methacrylate)-b-poly(oligo(propylene sulfide) methacrylate) (POEGMA-POPSMA) were prepared to fabricate PS via self-assembly in aqueous solution. As a type of unique drug delivery vehicle, the interior of the PS was co-loaded with hydrophilic molecules and water-soluble poly(N-isopropylacrylamide) (PNIPAM) conjugates. Due to the thermosensitivity of PNIPAM, PNIPAM conjugates within the PS aqueous interior underwent a phase transition to form hydrogels in situ when the temperature was raised above the lower critical solution temperature (LCST) of PNIPAM. Via control of the overall shell permeability by oxidation, we realized the sequential release of two water-soluble payloads based on the assumption that hydrogels have much smaller membrane permeability than that of molecular cargos. The ability to control the timing of release of molecular dyes and PNIPAM-based hydrogels was also observed within live cells. Furthermore, leakage of hydrogels from the PS was effectively alleviated in comparison to molecular cargos, which would facilitate intracellular accumulation and prolonged retention of hydrogels within the cell cytoplasm. Thus, we demonstrate that the integration of responsive hydrogels into PS with crosslinkable membranes provides a facile and versatile technique to control the stability and release of water-soluble cargos for drug delivery purposes.

Azo Coupling Reaction Induced Macromolecular Self-Assembly in Aqueous Solution.

This communication reported azo coupling reaction induced macromolecular self-assembly in aqueous solution. Diblock copolymer (PEG-b-PSNHBoc) consisting of a hydrophilic PEG block, and a hydrophobic N-Boc protected poly(p-vinylaniline) block was synthesized by RAFT polymerization. Then double hydrophilic diblock copolymer (PEG-b-PSN2+) composed of PEG and PS based macromolecular diazonium salts was prepared by the diazotization of PEG-b-PSNH2, which was obtained by deprotection of PEG-b-PSNHBoc. As N,N-dimethylaniline was gradually added into the freshly prepared PEG-b-PSN2+ aqueous solution, the azo coupling reaction between N,N-dimethylaniline and diazonium salts took place, which would lead to the generation of azobenzene pendants. Due to the poor solubility of azobenzene pendants in water, the formed hydrophobic polymeric chains aggregated to form the self-assembly colloidal particles. By incorporating a fluorescent group into the aniline, the aggregates formed through azo coupling reaction induced macromolecular self-assembly showed enzyme-triggered fluorescent behaviors.

Hemicellulosic Polysaccharides Mimics: Synthesis of Tailored Bottlebrush-Like Xyloglucan Oligosaccharide Glycopolymers as Binders of Nanocrystalline Cellulose.

We report in this contribution that while low molecular weight hemicellulosic building blocks are known not to interact with cellulosic materials, their multivalent presentation on a polymeric scaffold significantly enhanced the binding interactions that are remarkably in the same range as those usually observed for lectin-carbohydrate interactions. We developed a poly(propargyl methacrylate) scaffold on which we conjugated, by "post-click" reaction, a variety of azide reducing-end functionalized xyloglucan oligosaccharides with controlled enzymatic-mediated rate of degalactosylation. Bottlebrush-like xyloglucan oligosaccharide glycopolymers (poly(XGOn)) were obtained and their self-assemblies in aqueous solution were investigated using dynamic light scattering (DLS). We demonstrated that increasing the extent of degalactosylation promoted self-association of poly(XGOn), which we attribute to the appearance of hydrophobic domains. A sharp thermoresponsiveness, which corresponds to a decrease in aggregate size with increasing temperature, was observed when the extent of degalactosylation was 30% or greater. Importantly, isothermal titration calorimetry (ITC) and polarized/depolarized DLS revealed that poly(XGOn) exhibit a significant capacity to interact with nanocrystalline cellulose (NCC) surfaces particularly for the nondegalactosylated form, emphasizing the important role of galactosyl residues in the binding mechanism and in the 3-dimensional structures of glycopolymers.

Effect of OMC and MWNTC support on mass activity of Pd[sbnd]Co catalyst for formic acid electro-oxidation

The electrochemical evaluation of PdCo catalyst supported on Ordered Mesoporous Carbon (PdCo/OMC) synthesized by the polyol method is reported in this work. OMC is synthesized via self-assembly in aqueous solution, as an alternative route to conventional preparation methods. The electrocatalytic performance of PdCo/OMC is evaluated for Formic Acid Oxidation Reaction (FAOR). The results are compared with those of PdCo on Multi-Walled Carbon Nanotubes (PdCo/MWCNT) and Pd/OMC, prepared by the same procedure, with the aim to evaluate the effect of support and the Co contribution during the FAOR. The catalysts are characterized by scanning and transmission electron microscopy (SEM and TEM), X-ray diffraction (XRD) and small-angle X-ray scattering (SAXS). Cyclic voltammetry (CV) and chronoamperometric studies are carried out in acid media with different formic acid concentrations (0.1, 0.5 and 1 mol L−1). According to TEM results, PdCo/OMC exhibits smaller particle size (∼3.5 nm) and enhanced distribution of nanoparticles compared with PdCo/MWCNT. At 0.5 mol L−1 HCOOH, PdCo/OMC delivers a higher anodic mass current density (185 mA mg−1Pd) of the FAOR than PdCo/MWCNT (94.3 mA mg−1 Pd). Moreover, at 1 mol L−1 HCOOH the jf/jb ratio for PdCo/OMC is 1.09 mA mg−1Pd, higher than the ratios determined for PdCo/MWCNT (0.76) and Pd/OMC (0.85). The improvement of the mass catalytic activity of PdCo/OMC is attributed to the combination of the mesoporous structure of the support, which promotes the catalyst-support interaction facilitating the mass transfer process during the reaction, and to the incorporation of Co in the Pd structure.

Hydrophobically modified polyacrylates (hmPAAs) with long alkyl chains – Self-assembly in aqueous solution

Hydrophobically modified polyacrylates (hmPAAs) obtained by Atomic Transfer Radical Copolymerisation (ATRP) of mixtures of different alkyl acrylates and t-butyl acrylate and subsequent hydrolysis of the t-butyl acrylate to polyacrylic acid (PAA), were studied with respect to their aggregation behaviour in aqueous solution. The hydrophobic modifications were long alkyl chains that were varied systematically from dodecyl to stearyl, thereby expecting a strong propensity for hydrophobic aggregation. Their structure in aqueous solution was investigated comprehensively by small-angle neutron scattering (SANS) and complemented by dynamic light scattering (DLS) experiments. In these random copolymers the degree of amphiphilicity and hydrophobicity was varied by the percentage of alkyl chains and pH. Due to the length of the alkyl chain all these copolymers have a tendency for microphase separation, but this tendency and the structure of the formed hydrophobic domains depend in a systematic fashion on the precise molecular composition. The domain size scales with the length of the hydrophobic alkyl modification and, for chains of C16 and longer, there is apparently a tendency for elongation. Another interesting observation is that for 20 mol% hydrophobic modification rather self-contained and isolated hydrophobic micellar domains are formed. In contrast, the copolymers with 10 mol% alkyl modification contain interconnected hydrophobic domains as evidenced from the low-q scattering seen in SANS and confirmed by DLS observations. This tendency is further enhanced when fully charging the copolymers. In summary, the molecular design of such random amphiphilic copolymers allows in a nice way to control the aggregation state in solution.

Rational design of tetrahydrogeraniol-based hydrophobically modified poly(acrylic acid) as emulsifier of terpene-in-water transparent nanoemulsions

Amphiphilic copolymers based on renewable resources were involved as emulsifiers to prepare transparent terpene-in-water nanoemulsions. The amphiphilic copolymers are composed of hydrophobically modified poly(acrylic acid) (HMPAA) grafted with different fractions of hydrophobic bio-based tetrahydrogeraniol (THG) side chains. The well-defined PAA were synthesized by reversible addition fragmentation transfer (RAFT) polymerization in order to tune the number-average molar mass of the initial PAA. The self-assembly in aqueous solution of the HMPAA copolymers was investigated through the measurement of their critical aggregation concentration by viscometry, tensiometry, dynamic light scattering and the determination of their aggregation number by static light scattering. Series of oil-in-water nanoemulsions using dihydromyrcenol (DHM) terpene as dispersed phase and PAA-THG as emulsifier were prepared with different PAA-THG/DHM weight ratios and DHM/water weight ratios. The level of transparency of the emulsions was monitored though the transmittance value measured at 600nm and the measurements of the hydrodynamic diameter of droplets by dynamic light scattering. This study highlights that the structure of the PAAx-THGy is a key parameter to prepare terpene-in-water nanoemulsions with the required high level of transparency. The optimised structure of the emulsifier consists in a moderate degree of polymerization of PAA backbone (DP‾n,PAA≤180) along with an intermediate average degree of substitution in hydrophobic THG side chains (13≤DS‾≤32).

“Schizophrenic” self-assembly of dual thermoresponsive block copolymers bearing a zwitterionic and a non-ionic hydrophilic block

Several series of presumed dual thermo-responsive diblock copolymers consisting of one non-ionic and one zwitterionic block were synthesized via consecutive reversible addition-fragmentation chain transfer (RAFT) polymerization. For all copolymers, poly(N-isopropylmethacrylamide) was chosen as non-ionic block that shows a coil-to-globule collapse transition of the lower critical solution temperature (LCST) type. In contrast, the chemical structure of zwitterionic blocks, which all belonged to the class of poly(sulfobetaine methacrylate)s, was varied broadly, in order to tune their coil-to-globule collapse transition of the upper critical solution temperature (UCST) type. All polymers were labeled with a solvatochromic fluorescent end-group. The dual thermo-responsive behavior and the resulting multifarious temperature-dependent self-assembly in aqueous solution were mapped by temperature-resolved turbidimetry, 1H NMR spectroscopy, dynamic light scattering (DLS), and fluorescence spectroscopy. Depending on the relative positions between the UCST-type and LCST-type transition temperatures, as well as on the width of the window in-between, all the four possible modes of stimulus-induced micellization can be realized. This includes classical induced micellization due to a transition from a double hydrophilic, or respectively, from a double hydrophobic to an amphiphilic state, as well as “schizophrenic” behavior, where the core- and shell-forming blocks are inverted. The exchange of the roles of the hydrophilic and hydrophobic block in the amphiphilic states is possible through a homogeneous intermediate state or a heterogeneous one.

A Hetero-network Hydrogel With Self-assembled Nanofibers as Multiple-crosslinkers and Its Liquid-crystal-driven Healing Properties

Hetero-network hydrogels composed of hydrophilic polymers with terminal alkyl chains and nanofibrous self-assemblies were successfully fabricated. The gel formation was not observed in both cases of the self-assemblies in aqueous solution and hydrophilic polymer in aqueous solution. Furthermore the gel-to-liquid crystalline phase transition temperatures of nanofibrous self-assemblies were lowered by addition of hydrophilic polymers with terminal alkyl chains. From these observations, it was considered that the alkyl chains at polymer termini intercalated into the bilayer membrane-based nanofibrous self-assemblies to form cross-linking points. As far as we know, the hybrid hydrogel introduced in this communication is the first example of a hetero-network structure composed of supramolecular assemblies. When the hetero-network hydrogel was crushed by mechanical shearing, these hydrogels recovered by heating at temperatures above their gel-to-liquid crystalline transition temperatures.