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The creation of polymer composite materials by compositing fillers into polymer materials is an effective method of improving the properties of polymer materials, and the development of new fillers and their novel composite methods is expected to lead to the creation of new polymer composite materials. In this study, we develop a new filler material made of low-molecular-weight gelators by applying a gelation process that simultaneously performs the swelling (gelation) of crosslinked polymer materials and the self-assembly of low-molecular-weight gelators into low-dimensional crystals in organic solvents within polymer materials. The gelation process of crosslinking rubber-based polymers using alkylhydrazides/toluene as the low-molecular-weight gelator allowed us to composite self-assembled sheet-like crystals of alkylhydrazides as fillers in polymeric materials, as suggested by various microscopic observations, including infrared absorption measurements, small-angle X-ray diffraction measurements and thermal analysis, microscopy, and infrared absorption measurements. Furthermore, tensile tests of the composite materials demonstrated that the presence of fillers improved both the Young's modulus and the tensile strength, as well as the elongation at yield. Additionally, heat treatment was shown to facilitate filler dispersion and enhance the mechanical properties. The findings demonstrate the potential of self-assembled sheet-like crystals of low-molecular-weight gelators as novel filler materials for polymers. The study's composite method utilizing gelators via gelation proved effective. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Poly(ionic liquid)-based adsorbents were prepared through ionic self-assembly method. • The adsorbent showed fast adsorption and high adsorption capacity for anionic dyes. • The adsorbent can selectively remove anionic dyes from mixed dyes aqueous solutions. Abstract In this work, poly(ionic liquid)-based porous hybrid materials were facilely prepared through ionic self-assembly method and proposed as adsorbents for removal and separation of ionic dyes. PIL, namely poly-[ N , N -dimethyl-dodecyl-(4-vinylbenzyl)ammonium chloride], was synthesized by simple radical polymerization and directly assembled with the multi-charged anionic cluster of polyoxometalate (POM) to yield PIL/POM hybrid materials without involving any toxic organic solvents and tedious modification processes. The obtained hybrid materials were characterized by various techniques and utilized as adsorbents for removal of a variety of ionic dyes from water. By adjusting the proportion of PIL and POM in the hybrid materials, the adsorption capability and selectivity towards cationic and anionic dyes could be effectively regulated. The preferred adsorbent showed fast adsorption rate and large adsorption capacity, and was able to selectively remove anionic dyes from cationic/anionic mixed dyes aqueous solutions. Furthermore, the used adsorbent can be easily collected and regenerated. All the results demonstrate that the PIL/POM hybrid material is an efficient, durable and sustainable adsorbent in water purification treatment. [ABSTRACT FROM AUTHOR]

Organic solvent nanofiltration (OSN) is an emerging technology for molecular separation and purification in organic media. The separation performances are mainly depended on the material and structure of the membrane. In this study, Zeolitic Imidazolate Framework (ZIF-8) nanoparticles were in situ growth onto the surface of graphene oxide (GO) sheets to form ZIF-8@GO composites, which were co-deposited with polyethyleneimine (PEI) matrix on tubular ceramic substrate through a vacuum-assisted assembly method. The dispersion of ZIF-8 nanoparticles in PEI matrix as well as the compactness and uniformity of the composite membranes were readily improved due to the templating effect of lamellar GO sheets and the transmembrane pressure. Membrane performance in OSN was evaluated on the basis of methanol permeance and retention of dye molecules. Methanol permeance increased when ZIF-8@GO laminates were embedded into the PEI layer, whereas the retention remained higher than 99%. The improvement of separation performance may be due to the well dispersion of ZIF-8 nanoparticles in PEI matrix, which offers more well-defined pathways for solvent molecules. Building on these findings, we demonstrate a simple scalable method to obtain robust ZIF-8@GO based membranes with enhanced OSN performance. [ABSTRACT FROM AUTHOR]

A self-assembly strategy has been developed for the synthesis of anion-exchange membranes (AEMs) with high alkaline stability. Cardo poly(aryl ether sulfone ketone)s with pendent tertiary amine groups were grafted with alkyl siloxane to form a polymer with cation quaternary ammonium groups. This polymer produced a zwitterionic polymer via partially hydrolysis of the alkyl siloxane in weak basic medium. The flexible and transparent zwitterionic polymer membranes possessing a Si-O-Si cross-linked network were prepared via the sol-gel polycondensation reaction and a self-assembly process. The homogeneous and continuous Si-O-Si cross-linked network inhibited membrane swelling and improved the mechanical properties and thermochemical stability. The membrane showed alkaline stability in 1 M NaOH aqueous solution at 60 °C for 600 h and solvent resistance in polar aprotic solvents (DMAc, NMP, and DMSO) at 60 °C for 30 days. [ABSTRACT FROM AUTHOR]

The solvophobic effect is a driving force for self-assembly processes that acts in protic molecular organic solvents as well as in both protic and aprotic ionic liquids. It is known to reduce the solubility of apolar compounds and influence the magnitudes of thermodynamic functions of solvation in molecular solvents. In ionic liquids, thermodynamic aspects of the solvophobic effects have not yet been carefully considered. By comparing the relations between the Gibbs free energy and enthalpy of solvation of different compounds, we show that the solvophobic effect in aprotic ionic liquids can be even stronger than in organic solvents forming a network of intermolecular hydrogen bonds, such as formamide and ethylene glycol. The strength of the solvophobic effect expressed in terms of energy contributions is correlated with the average number of ions per unit volume, which is inversely proportional to the molar volume of the liquid. It is shown that the solvophobic effects become stronger when we change the cation or anion of the ionic liquid with another of a smaller size, and can be extremely weak when the cation contains long alkyl chains, but they are a general phenomenon for all ionic liquids. [ABSTRACT FROM AUTHOR]

N-doped graphene aerogel with a three-dimensional interconnected network was fabricated by using graphene oxide and melamine via the hydrothermal self-assembly and thermal annealing process. The aerogels were characterized by means of scanning and transmission electron microscopy, Fourier transform infrared spectrum, X-ray photoelectron spectroscopy, elemental analyses, X-ray diffraction, Raman spectrum, and nitrogen adsorption/desorption measurement. The N-doped graphene aerogel showed high-specific surface area, superhydrophobic nature, excellent adsorption capacity for organic solvents, and adsorption recyclability. It would be a promising material for removal of organic contaminates from water. [ABSTRACT FROM AUTHOR]

Degradation and denaturation of labile biomolecules during preparation of micelles by organic solvent at high temperature are some of the limitations for fabrication of advanced polymer based protein delivery systems. In this paper, effectiveness of heat–chill method for preparation of micelles containing large labile biomolecules was investigated using insulin as a model protein molecule. Micelles (average size, <120 nm) were prepared using amphiphilic diblock and triblock copolymers of poly(ethylene glycol) (PEG) and poly(ϵ-caprolactone) (PCL). Micelles were prepared by heating PEG–PCL block copolymers with distilled water at 60 °C followed by sudden chilling in an ice-water bath. Effects of molecular architecture on morphology, stability and protein loading capacity of micelles were investigated. Micelles prepared using high molecular weight block copolymers exhibited good colloidal stability, encapsulation efficiency and insulin release characteristics. Insulin retained its secondary structure after micelles preparation as confirmed by CD spectroscopic study. Furthermore, in vitro cytotoxicity test suggested that the prepared micellar nanoparticles possessed biocompatibility. In a nut shell, heat–chill method of micellar nanoparticles preparation is well suited for encapsulating labile proteins and other allied biomolecules which degrade in presence of toxic organic solvents and at elevated temperatures. [ABSTRACT FROM AUTHOR]

Self-assembly of hierarchical graphene oxide (GO)-based nanomaterials with novel functions has received a great deal of attentions. In this study, nanostructured organogels based on cationic amphiphile-GO composites were prepared. The gelation behaviors of amphiphile-GO composites in organic solvents can be regulated by changing the headgroups of amphiphiles. Ammonium substituted headgroup in molecular structures in present self-assembled composites is more favorable for the gelation in comparison to pyridinium headgroup. A possible mechanism for headgroup effects on self-assembly and as-prepared nanostructures is proposed. It is believed that the present amphiphile-GO self-assembled system will provide an alternative platform for the design of new GO nanomaterials and soft matters. [ABSTRACT FROM AUTHOR]

Highlights: [•] Two fluorescent BAB-type block copolymers were prepared by ATRP. [•] The copolymers are totally soluble in common organic solvents. [•] The self-assembly aggregate sizes of the copolymers show evident conc. dependence. [•] The micelles transform to pearl-necklace-like aggregates when conc. above 1000ppm. [Copyright &y& Elsevier]

Highlights: [•] PDMS-b-PHFBMA is a novel fluorosilicone double-hydrophobic block copolymer. [•] The micellization of PDMS-b-PHFBMA in organic solvent was investigated in detail. [•] Different factors were employed to induce the morphology transition. [•] Abundant morphologies for micelles were found in this system. [•] A classical thermodynamic model was applied to describe the mechanism of aggregation. [ABSTRACT FROM AUTHOR]

Abstract: Porphyrin metal (Zn, Cu, and Mg) complex monolayer-protected gold nanorods (GNRs) were, for the first time, synthesized. Their synthesis was easy to access by mixing porphyrin encapsulated GNRs with corresponding excess soluble metal salts in solution, followed by the facile purification through centrifugation and sonication due to the gravity of the GNRs and their solubility in organic solvents. Furthermore, the resulting three GNRs exhibited distinct spectroscopic properties and were able to self-assemble into side-by-side arrays driven by π–π intermolecular interactions of the surface metal porphyrin chromophores. [Copyright &y& Elsevier]

Theconformational properties and aggregation behavior of two selectivelymodified cyclomaltooligosaccharides (cyclodextrins, CDs) containinga double-linked 1,8-dimethylnaphthalene cap-like moiety at the secondaryface, namely, 2I,3I-O-(1,8-dimetylnaphthalene-α,α′-diyl)-per-O-Me-α- and -γ-cyclodextrins (NmαCD and NmγCD, respectively), in waterand in organic solvents were investigated. Both CD derivatives self-associatedin water to form dimer species, but the characteristics of the dimerizationprocess and of the resulting dimer strongly depended on the size ofthe macrocycle. Dimerization constants, thermodynamic parameters uponassociation, and information about the preferred conformations ofthe monomer and dimer CD structures were obtained by using NMR, UV–vis,steady-state and time-resolved fluorescence, and circular dichroismexperimental techniques, as well as molecular mechanics (MM) and moleculardynamics (MD) simulations. The complexation of 1,8-di(methoxymethyl)naphathalene(oNy) and the heteroassociation of both NmCDs withtheir permethylated CD partners (mCDs), lacking thearomatic cap, were examined. In addition, the influence of the sizeof the chromophore moiety on the thermodynamics of self-associationwas also assessed by comparison of the results obtained for the newnaphthalene derivatives with those of the 2I,3I-O-(1,2-xylylene)-modified CD analogues (XmCDs). [ABSTRACT FROM AUTHOR]

Lipophilic guanilic derivatives (lipoGs) dissolved inorganic solventscan undergo different self-assembly pathways based on different H-bondedmotifs, e.g., the cyclic discrete G-quartet, which forms in the presenceof alkali-metal ions, and the “infinite” tape-like G-ribbonobserved in the absence of ions. Using in-solution small-angle X-rayscattering, we analyzed a series of lipoGs dissolved in cyclohexanein the presence of different salts. The formation of G-quartet basedsupramolecular aggregates has been confirmed, evidencing the coexistenceequilibrium of octamers and noncovalent molecular nanowires (the so-calledG-quadruplexes). By global fitting the scattering data, the concentrationof the two kinds of particles as well as the nanowire length havebeen derived as a function of temperature for the different compoundsand salts. The thermodynamic parameters show that the self-assemblyaggregation process is enthalpy driven, while the observed enthalpy–entropycompensation suggests that similar stacking interactions control theself-assembly of the different compounds. However, the strength ofthe stacking interactions, and then the nanowire stability, dependson the nature of templating cations and on their capacity to fillthe central cavity of quadruplexes, with the order Sr+

The gelation behaviors of binary organogels composed of aminobenzimidazole/benzothiazole derivatives and benzoic acid with single-/multialkyl substituent chain in various organic solvents were designed and investigated. Their gelation behaviors in 20 solvents were tested as new binary organic gelators. This showed that the number and length of alkyl substituent chains and benzimidazole/benzothiazole segment have played a crucial role in the gelation behavior of all gelator mixtures in various organic solvents. More alkyl chains in molecular skeletons in present gelators are favorable for the gelation of organic solvents. The length of alkyl substituent chains has also played an important role in changing the gelation behaviors and assembly states. Morphological studies revealed that the gelator molecules self-assemble into different aggregates from wrinkle, lamella, belt, to fiber with change of solvents. Spectral studies indicated that there existed different H-bond formation and hydrophobic force, depending on benzimidazole/benzothiazole segment and alkyl substituent chains in molecular skeletons. The prepared nanostructured materials have wide perspectives and many potential applications in nanoscience and material fields due to their scientific values. The present work may also give new clues for designing new binary organogelators and soft materials. [ABSTRACT FROM AUTHOR]

We reported here the gelation behaviors of two-component organogel system based on different acids and aminobenzothiazole derivatives in various organic solvents. Their gelation behaviors in 20 solvents were tested as new organic gelators. It was shown that the molecular skeletons and substituted groups in these compounds played a crucial role in the gelation behavior of the mixtures. Only the binary mixture of 2-aminobenzothiazole and trigonal 1,3,5-benzenetricarboxylic acid with aromatic core could form organogels in ethanol and acetone. Morphological observations reveal that the microstructures of both xerogels showed similar wrinkle-shaped domains composed of sheet-like aggregates with many holes. Spectral studies reveal the hydrogen bonding interaction between the amide of the gelator and lamellar-like structure of the aggregates in both gels. The present investigation is a perspective to provide new clues for the design of new nanomaterials and functional textile materials with special microstructures. [ABSTRACT FROM AUTHOR]

New benzimidazole/benzothiazole imide derivatives with different alkyl substituent chains were designed and synthesized. Their gelation behaviors in 22 solvents were tested as novel low-molecular-mass organic gelators. The test showed that the alkyl substituent chains and headgroups of benzimidazole/benzothiazole residues in gelators played a crucial role in the gelation behavior of all compounds in various organic solvents. More alkyl chains in molecular skeletons in present gelators are favorable for the gelation of organic solvents. SEM and AFM observations revealed that the gelator molecules self-assemble into different aggregates from wrinkle, lamella and belt to dot with change of solvents. Spectral studies indicated that there existed different H-bond formation between imide groups and hydrophobic force of alkyl substituent chains in molecular skeletons. The present work may give some insights into design and character of new organogelators and soft materials with special molecular structures. [ABSTRACT FROM AUTHOR]

A novel amphiphilic, unsymmetrically substituted N-((2S)-2-aminohexanoic acid)-N'-[(S)-l-phenylethyl]-3,4,9,10-perylenetetracarboxydiimide with 2 different chiral centers was synthesized and characterized. Chiral amphiphilicity, which can be tunable between hydrophilic and hydrophobic parts, is responsible for controlled self-assembly through intermolecular hydrogen bonding (N-H … O). The product showed high thermal stability but partial solubility in common organic solvents. We observed 2 isosbestic points at 533 and 611 nm, confirming the presence of overlapped monomer and excimer emissions in the temperature range of 10-80 °C. Fluorescence quenching in m-cresol was attributed to charge-transfer interactions. Importantly, the excited state of the chiral dye can decay only by fluorescence in the solid state, mainly due to O-H … N hydrogen bonds. Novel red-light-emitting (λem = 658 nm) chiral perylene dye has a great potential for solid-state lighting technologies. [ABSTRACT FROM AUTHOR]

This study modifies the authors' previously reported directed self-assembly (DSA) process of polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) in order to meet the throughput and material-related requirements of a semiconductor manufacturing environment. It is demonstrated that all of the bottleneck steps in the authors' DSA process, including the deposition of the cross-linkable mat and the deposition of the brush layer, can be done in minutes on a hot plate in an N2 atmosphere, which simulates the processing environment of a lithography track module. A 25-nm-pitch pattern resulting from a 4:1 density multiplication was demonstrated with a manufacturing-compatible organic solvent. A preliminary uniformity study on 300 mm wafers was also presented. The modified DSA process presents a viable solution to some of the anticipated throughput-related challenges to DSA commercialization and thus, brings integration of DSA within reach of the semiconductor manufacturing industry. [ABSTRACT FROM AUTHOR]

We report on studies of the tailored self-assembly of the perylene diimide derivative, N,N′-ditridecylperylene-3,4,9,10-tetracarboxylic diimide, into structures with fibrous gel-type, one-dimensional, and two-dimensional morphologies. This approach for producing highly ordered nanostructures of well-defined morphologies utilizes a property of π-conjugated molecules to assemble in poor organic solvents due to π–π interaction between the aromatic cores and takes advantage of the temperature dependence of solubility. The morphology control is based on a fine-tuning of anisotropic, intermolecular solute–solute interactions that are attenuated by the solute–solvent interaction in organic solvents of different chemical structure. We discuss the role of light illumination in the self-assembly process as well as application of ultrasonic treatment as a way of mechanical tailoring of morphology. This approach paves the way toward the molecular-scale tailoring of structural properties of organic semiconducting materials for electronic and optoelectronic applications. [ABSTRACT FROM AUTHOR]

Abstract: A new organogelator, N-Carbobenzoxy-l-Valine-Hexadecane Hydrazide (designated as Cbz-Val-HdHz) was synthesized, which can self-assemble in various organic solvents and turned them into thermally reversible physical supramolecular organogels at extremely low concentrations (<2wt%). The effect of solvent polarity on the gelation properties was studied by using the Kamlet–Taft model. The gel–sol temperatures (T GS) were determined as a function of gelator concentration and the corresponding enthalpies (ΔH g) were extracted. Scanning electron microscopy (SEM) measurements revealed that the gelator self-assembled into different supramolecular network structures in different gels. FT-IR spectroscopy studies revealed that intermolecular hydrogen bonding between N–H and Ce group and hydrophobic interaction of the alkyl groups were the driving forces for the formation of the gels. Based on the data of XRD and molecular modeling, the possible packing modes for the formation of organogelator aggregates were proposed. [Copyright &y& Elsevier]

Abstract: We present a process for the phase-transfer of gold nanoparticles from an aqueous to an organic medium with normal alkanethiols. This method can be applied not only to large nanospheres (d ∼100nm) but also to anisotropic nanoparticles like nanorods and nanoplates. It allows the comparison of the nanoparticle optical properties when they are dispersed in both aqueous and organic media. [Copyright &y& Elsevier]

Abstract: We present the first report on the synthesis of chiral ureas, (R)- and (S)-2-heptylurea, and their gelling behaviors. The ureas were prepared by the reactions of chiral amines and phenyl carbamate in the presence of triethylamine. On cooling from homogeneous solutions, the chiral ureas form gels in water and various nonpolar organic solvents, such as cyclohexane, toluene, and tetrachloromethane, while the racemate gelatinize only toluene and tetrachloromethane among the solvents we examined. The gelling ability of the enantiomeric urea is higher than the racemate, as the critical gelling concentrations in toluene, for example, were 0.2% and 0.7% (wt/wt), respectively. The enhanced gelling ability of the enantiomeric ureas is due to the 1D supramolecular structure formed during gelation. In contrast, the racemate crystallizes into two-dimensional lamellae, where the (R)- and (S)-2-heptylurea exist alternatingly in a plane (P21/c space group). Powder X-ray diffraction pattern of the enantiomeric urea showed that it has a different crystal lattice from that of the racemate, implying that the steric effect by the methyl group at the chiral center prevents the pure enantiomers from having 2D hydrogen bonding networks, which lead to sheet-like structures for the racemate and the achiral analog. Thus the pure enantiomers self-organize into one-dimensional fibrous structures. The simplicity and the ambidextrous gelling behaviors of the chiral ureas in forming both hydrogels and organogels present numerous possibilities for future applications. [Copyright &y& Elsevier]

Abstract: The size-controllable and highly monodispersed cuboidal barium strontium titanate (BST) nanocrystals have been successfully synthesized through a glycothermal process with no mineralizers but oleic acid as growth-directing agent. The synthesized BST nanocrystals under different glycothermal conditions were structurally characterized by XRD, IR, FESEM, TEM and HRTEM and investigated with respect to the effects of key influencing factors including the amount of oleic acid, duration of glycothermal process and 1,4-butanediol/water volume ratio in the reaction media on the formation of BST nanocrystals and their size and morphological evolution. It has been found that the oleic acid incorporated into the glycothermal system plays a decisive role in promoting the formation of cuboidal nanocrystals. It allows the BST nanocrystals to form via a nucleation-growth mechanism instead of in situ reactions and the selective chemical adsorption of oleic acid molecules on the facets with lower plane indices of newly-built BST nuclei directs them to grow into uniform cuboidal BST nanocrystals. The duration of glycothermal reactions and the polarity of reaction media can remarkably affect the dynamic process of the formation of BST nanocrystals. These regularly-shaped and highly monodispersed nanocrystals show a spontaneity of self-assembling into 2D ordered architectures when they were dispersed in organic solvents like cyclohexane and droped onto a hydrophobic surface of substrates, which creates a chance for the ferroelectric oxide nanocrystals to self-assemble into nanoscale electronic devices. [Copyright &y& Elsevier]

Abstract: The mesomorphic dihydrazide derivatives N,N′-bis(4-n-alkyloxybenzoyl) hydrazine (Cn) showed stable liquid crystalline properties and strong gelation ability in organic solvents, and showed environmentally tuned self-assembled structures. On heating, Cn (n=7, 12, 16) exhibit thermotropic cubic phase with Pn3m symmetry; while in the gel phase, molecules of Cn self-assembled into higher ordered monolayer structure, which is the fundamental of the fibrous aggregates observed by SEM. Intermolecular hydrogen bonding between the dihydrazide groups was demonstrated to be the major driving force for both gelation of organic solvents and stabilization of the liquid crystalline phase. [Copyright &y& Elsevier]

An azobenzene-containing lipid was designed as a functional organogelator, and its self-assembly as well as the chiroptical properties were investigated. The gelator shows good gelation ability in various organic solvents ranging from polar to nonpolar solvents. Although the molecule did not show a CD signal in the absorption band of azobenzene in solution, supramolecular chirality was observed upon gel formation. Moreover, the supramolecular chirality exhibited a multiresponse to temperature, photoirradiation, and the solvent polarity. Particularly, positive supramolecular chirality was observed in polar solvents, while it inverted to a negative one in nonpolar solvents. All the responses in relating to the supramolecular chirality were reversible and thus produced a multiresponsive chiroptical switch. [ABSTRACT FROM AUTHOR]

Abstract: This study focuses on a facile approach to create N-[3-trimethoxysilyl)propyl]diethylenetriamine (C10H27N3O3Si, TRIS in short) self-assembled monolayers (SAMs) on silica particles for water treatment without the use of any organic solvents. A range of TRIS concentration has been examined to establish the window of SAM formation. In order to determine the coverage and characterise the stability of the TRIS-monolayer, the active amine functional groups of the monolayer are quantitatively characterised by titration method. Its thermal stability and TRIS uptake are characterised by thermogravimetric analysis (TGA) and the analysis is correlated with a model calculation of the maximum TRIS-coverage considering the surface area of hydroxyl (OH) concentration on the surface of the silica particles. X-ray photoelectron spectroscopy (XPS) analyses clearly reveal the existence of the TRIS-monolayer on the particles. The TGA results show TRIS-layers are stable up to 225°C and fully degraded at 650°C. The determined weight loss (%) correlates within the analytical error with the values determined by titration. Monolayer formation is observed only up to low concentration of TRIS (0.32mmol/g) and above which it is predominated by the formation of multilayer. The correlation of the experimental results with model calculations of the maximum TRIS-coverage confirms this effect to be due to TRIS-multilayer formation. [Copyright &y& Elsevier]

Abstract: We developed a newly developed macromolecular assembly, a trilayered polymeric micelle, which can encapsulate hydrophilic compounds. The optimal condition for preparing a stable w/o emulsion was determined by the evaluation of several factors such as the composition of phase-forming organic solvents and the concentration of an emulsion stabilizer. Then, the trilayered polymeric micelle was prepared under the optimal condition for preparing the stable w/o emulsion. The results of DLS, GPC, 1H NMR, and fluorescence microscopy suggested that the trilayered polymeric micelle was successfully prepared. It was also clarified that the micelle can encapsulate the model hydrophilic compound, FITC-dextran, into the core of the micelle. The micelle can be expected to incorporate/release compounds effectively by means of the possible optimization of the entanglement of PLA segments forming the shell layer of the micelle. These features strongly suggest that the micelle can have a variety of future applications, especially in medical fields. [Copyright &y& Elsevier]

Self-assembly behaviors of polymer-tethered nanorods in the selective solvent are systematically investigated via a dissipative particle dynamics (DPD) simulation method. Three types of polymer-tethered nanorods are considered: one end tethered, both ends tethered, and middle tethered. The solvent-induced diverse morphologies and morphological transitions depend on the topology, rod/tether length ratio, solvent selectivity, and mixed solvent content. In the pure rod-selective solvent (solvent I) or the pure tether-selective solvent (solvent II), the ordered micellar structures include: cylinders, hexagonal cylinders, bilayer lamellae, lamellae/cylinder mixed phases, inverted hollow cylinders, and nematic bundles. These micelles are formed by the competition among the stretching of tethers, liquid crystalline of rods, interfacial energy, and solvent selectivity. In the I/II mixed solvent, with varying mixed solvent content in sequence (i.e., changing the solvent quality for the blocks), the reversible morphological transitions and fantastic intermediate phases (e.g., liquid crystalline phase) are observed, which correspond directly to the case of that induced by varying the rod/tether length ratio in the pure solvent. It is concluded that improving the selective solvent content is equivalent to increasing the soluble block ratio. The present study reveals that the morphology and morphological transition of polymer-tethered nanorods could be significantly manipulated through topology, block length, and solvent, especially the selectivity. [ABSTRACT FROM AUTHOR]

From a red proton complex of aldehyde derivatives of polyaromatic hydrocarbon with strong intermolecular hydrogen bonding, which are novel examples of intermolecular proton-bonded aldehydes of polyaromatic hydrocarbons, we find one-dimensional proton arrangement. The complex formed as 9-antraldehyde (Ant-CHO) reacts with HAuCl4to form [(Ant-CHO)2H]+[AuCl4]−under dry condition, which are confirmed by single-crystal structure determination and infrared spectra analysis at varying temperatures. Since the compounds of distinctively hydrophobic nature are soluble only in limited organic polar solvents, the strong hydrogen bonds are clearly observed from both the electron density of X-ray analysis and the characteristic signature of the IR frequency. The proton complex units have the typical O−H+−O distance of the strong hydrogen bond similar to the Zundel-like cationic hydrogen bond (where two O atoms share a proton in the midpoint of the short O−O distance of ∼2.4 Å). The chemical shift of 20.18 ppm originated from the protons of the O−H+−O hydrogen bonds would be the largest downfield shifted value among those of protons in O−H···O bonds reported in various solid materials, indicating very short strong hydrogen bonds for the O−H+−O. The complexes are stabilized with the π−π intermolecular interactions of the polyaromatic hydrocarbon ligands, resulting in layered structures. The spectral signatures around ∼900, ∼1200, and ∼1700 cm−1for the Zundel-like proton bond are clearly characterized. [ABSTRACT FROM AUTHOR]

Abstract: Various zinc oxide (ZnO) nanostructures were prepared in different polar organic solution of NaOH via a facile self-assembly solvothermal growth process. ZnO nanoparticles, nanowires, nanorods and nanoneedles with different sizes were fabricated depending on the properties of polar organic solvents. The effects of polar organic solvents including methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, acetone and isopropanol on the forms and morphologies of ZnO nanostructures were investigated, and the corresponding reaction mechanism was preliminarily proposed. The corresponding photoluminescence (PL) spectra exhibited different optical properties of the ZnO nanostructures. We deduce that surface defects of the nanostructures are the main reason for the PL properties observed in the ZnO nanostructures. It is found that the larger specific surface area, the more surface defects and the lower ultraviolet (UV) emission intensity are. [Copyright &y& Elsevier]

Biodegradable poly(ε-caprolactone)/poly(ethylene glycol) (PCL/PEG) copolymer nanoparticles showed potential application in drug delivery systems. In this article, monodisperse poly(ε-caprolactone)/poly(ethylene glycol)/poly(ε-caprolactone) (PCL/PEG/PCL, PCEC) nanoparticles, ∼40 nm, were prepared by solvent extraction method using acetone as the organic solvent. These PCL/PEG/PCL nanoparticles did not induce hemolysis in vitro and did not show toxicity in vitro or in vivo. The prepared PCL/PEG/PCL nanoparticles were employed to load doxorubicin by a pH-induced self-assembly method. In vitro release study indicated that doxorubicin release from nanoparticles at pH 5.5 was faster than that at pH 7.0. The encapsulation of doxorubicin in PCL/PEG/PCL nanoparticles enhanced the cytotoxicity of doxorubicin on a C-26 cell line in vitro. Meanwhile, compared with free doxorubicin, doxorubicin in nanoparticles could more efficiently treat mice bearing subcutaneous C-26 tumors. The doxorubicin-loaded PCL/PEG/PCL nanoparticles might be a novel doxorubicin formulation for cancer therapy. [ABSTRACT FROM AUTHOR]

Abstract: We report on the synthesis of gold nanoparticles (Au-NP) stabilized by a layer of mercapto and/or hydroxyl bola palmitic acid–tetrabutyl ammonium salts (TBAOH) which form nanosomes in water. Mixing both bola fatty acids in water in various proportions allowed to tune the nanoparticle diameter from 1 to 10nm using NaBH4 as a reductor. Those nanoparticles could be phase transferred to dichloromethane by adding a more hydrophobic counter-ion than TBAOH, its derivative with octyl chains (TOAOH). Finally, we used those Au-NP to formulate emulsions, the stability of which was followed as a function of particle size and time. The emulsions were stable but creamed after several hours. We conclude that bola fatty acid nanosomes are then good candidates to synthesize gold nanoparticles dispersed either in water, organic solvents and emulsions. [Copyright &y& Elsevier]

Abstract: A family of low molecular weight organogelators (LMOG) based on monochain derivatives of ethylenediamine were investigated. The monochain derivatives of ethylenediamine show strong gelation ability in a number of organic solvents, including polar solvents and non-polar solvents. In gel state, molecules of monochain ethylenediamine derivatives self-assemble into ordered aggregates, which are juxtaposed and interlocked to form three-dimensional networks of fiber bundles as confirmed by scanning electron mircroscopy (SEM). The Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) studies demonstrate that intermolecular hydrogen bonds between neighboring molecules are critical factor in the process of organogelation. [Copyright &y& Elsevier]

Abstract: We have developed a new approach involving the use of pressure during the alternating physisorption of oppositely charged polyelectrolytes on porous supports. For example, new polyelectrolyte multilayers (PEMs) as selective skins in composite membranes for NF were prepared by alternating layer-by-layer deposition of sulfonated poly (ether ether ketone) (sPEEK) and branched polyethyleneimine (PEI). During this electrostatic self-assembly deposition, it was demonstrated that the use of pressure could increase the salt rejection of the PEMs by one to two times. The effect of polymer charge density on membrane performance, e.g. sulfonation degree of sPEEK, was also studied. By depositing the sPEEK dissolved in methanol and branched PEI dissolved in water, the rejection of the PEMs could be further increased. The rejection is about 89% and very close to that of current commercially successful polyamide membranes, which is about 96%. The antifouling property of the PEMs has also been studied. Our membranes have a better antifouling property in comparison with commercial membranes, NTR 7450. [Copyright &y& Elsevier]

We describe the preparation of nanostructured polymeric materials by polymerizing a monomer within a scaffold composed of self-assembled nanofibrils. 1,3:2,4-Dibenzylidene sorbitol (DBS) is an inexpensive sugar derivative that can form nanofibrillar networks in a variety of organic solvents at relatively low concentrations. Here, we induce DBS nanofibrils in styrene and then thermally initiate the free-radical polymerization of the monomer. The polymerization proceeds without any evidence of macroscopic phase separation, ultimately yielding a transparent solid of polystyrene. Within this material, intact DBS nanofibrils (diameter 10−100 nm) are preserved, as shown by atomic force microscopy (AFM). The DBS fibrils can also be subsequently extracted from the polymer, leaving behind a network of nanoscale pores. The porosity of the resulting polymer has been characterized by the BET technique. [ABSTRACT FROM AUTHOR]

Abstract: A facile strategy was proposed for synthesizing chitosan-O-poly(ε-caprolactone) (CS-O-PCL). Stoichiometric sodium dodecyl sulfate–chitosan complex (SCC) which was soluble in common organic solvents was adopted as an intermediate. Regioselective conjugation of PCL onto SCC could be achieved through condensation reaction between isocyanate-terminated PCL and hydroxyl groups of chitosan. The grafting level of PCL could be modulated by varying PCL/SCC weight ratio. SDS was removed from SCC-O-PCL using trihydroxymethylamine (Tris) as a decomplexation agent. The self-assemble behavior of the amphiphilic copolymers was studied by fluorometry, TEM and laser light scattering. The morphology of the CS-O-PCL nanoparticles was found to be dependent on PCL grafting level. Both spherical micelles and vesicle could be formed by dialysis method. [Copyright &y& Elsevier]

Abstract: The influence of various water–glycol mixed solvents on the self-assembly of 1-hexadecylpyridinium chloride (CPyCl) was investigated using electrical conductivity and spectroscopic measurements. Temperature studies were performed in aqueous mixtures of ethylene, diethylene, triethylene and tetraethylene glycols (abbreviated as EG, DEG, TEG and TeEG, respectively). The correlation among critical micellization concentration (cmc) and degree of ionization (β) was discussed in term of thermodynamic parameters or the changes in the Gibbs free energy, enthalpy and entropy upon micelle formation (, and ). The differences in the Gibbs energies of micellization of CPyCl between water and binary solvents were determined to evaluate the influence of the cosolvent. This study allowed us to conclude that the ability of glycols to act, as a structure breaker and its interaction with the surfactant hydrophilic groups are the controlling factors of the micellization process. The effect of cosolvents on the size of the aggregates was analyzed by means of density measurements. Micellar micropolarity and solute solvent parameters were examined spectrophotometrically using methyl orange (MO) as a probe. The increase in micellar microviscosity was revealed from fluorescence measurements. The mechanism of docking of surfactant and the probe molecules in the system were obtained by using Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) spectroscopy. [Copyright &y& Elsevier]

Abstract: Chitosan (CS) based nanoparticles (NPs) have several advantages in delivering drugs. They are usually prepared in a micro-emulsion solvent system but this route can leave significant levels of potentially harmful organic solvent residue in the NPs. In this study, we prepared CS based nanocomposites using charge driven self-assembly in an aqueous buffer, thus avoiding the use of organic solvents. Doxorubicin (DOX) was covalently attached to positive charged CS with a legumain substrate peptide to confer targeted drug release property, since legumain is often overexpressed in tumors or tumor associated micro environments. This DOX prodrug solution interacted with negative charged methoxyl poly (ethylene glycol)-block-poly (glutamic acid) copolymer (PEG-PGA) in an aqueous buffer forming nanocomposite with a regular morphology. The particle size and zeta potential of these NPs was regulated by the addition of different PEG-PGA concentrations into the DOX prodrug solution. Due to its potential for legumain triggered release, this DOX NP exhibited enhanced cytotoxicity against choroidal melanoma cell line (Mum-2C) and reduced cytotoxicity on normal human corneal epithelial cells (HCEC), suggesting a good potential for enhanced targeted delivery of chemotherapeutic agents.A chitosan based nanocomposite with legumain sensitive properties are rapidly controllable prepared in aqueous buffer by charge driven self-assembly strategy, without using micro-emulsion solvent system and cross-linking agents. [ABSTRACT FROM AUTHOR]