Demonstration of Solvent-Induced One-Dimensional Nonionic Reverse Micelle Growth

We report formulation and free morphology switching of nonionic surfactant reverse micelles in nonpolar solvent alkylbenzene. Microstructure transformations of nonionic reverse micelles depending on the solvent molecular architecture under ambient conditions and their thermoresponsive behavior have been investigated using small-angle X-ray scattering (SAXS) and rheometry

Demonstration of a Novel Charge-Free Reverse Wormlike Micelle System

We demonstrate a novel charge-free reverse wormlike micelle (RWLM) consisting of a ternary mixture of a nonionic amphiphilic block copolymer, fatty acid alkyl ester oil, and water under ambient conditions. Nonionic amphiphile tetra-[poly­(oxyethylene)-poly­(oxybutylene)]­pentaerythrityl ether (TEBPE) self-assembled into spheroid-type micelles in nonaqueous media isopropyl myristate (IPM) with viscosity comparable to that of IPM. The addition of water increases viscosity only slightly up to a certain concentration of water and then drastically, demonstrating the sphere-to-wormlike micelle transition as confirmed by small-angle X-ray scattering. Further increase in water decreases the viscosity after attaining a maximum value. The zero shear viscosity (η₀) of the 10 wt % TEBPE/IPM system reached the maximum at 2.6 wt % water and ca. 56 Pa·s, which is ∼fivefold higher than that of water. Dynamic rheological measurements on the highly viscous solutions confirmed the viscoelastic behavior and could be described by the Maxwell model. Conductivity, measured in the presence of a conductive probe, 1-ethyl-3-methylimidazolium tetrafluoroborate, was found to be higher for viscous samples compared to the nonviscous samples, suggesting the static percolation caused by the RWLM formation. Decrease in η₀ and conductivity beyond a maximum suggests the shortening of reverse micelles. A similar behavior has been observed in other fatty acid alkyl ester oils of different alkyl chain lengths. Note that most of the RWLM systems previously reported are based on phosphatidylcholine (PC). Formulation and structure–properties related to non-PC-based RWLMs have been rarely explored. Non-PC-based RWLMs using chemically stable and low-cost synthetic molecules can be applied not only in pharmaceuticals and cosmetics but also in a wide range of applications including drag reduction agents for nonaqueous fluids and as a template for nanomaterial synthesis

Demonstration of Ultrarapid Interfacial Formation of 1D Fullerene Nanorods with Photovoltaic Properties

We demonstrate ultrarapid interfacial formation of one-dimensional (1D) single-crystalline fullerene C₆₀ nanorods at room temperature in 5 s. The nanorods of ∼11 μm in length and ∼215 nm in diameter are developed in a hexagonal close-pack crystal structure, contrary to the cubic crystal structure of pristine C₆₀. Vibrational and electronic spectroscopy provide strong evidence that the nanorods are a van der Waals solid, as evidenced from the preservation of the electronic structure of the C₆₀ molecules within the rods. Steady state optical spectroscopy reveals a dominance of charge transfer excitonic transitions in the nanorods. A significant enhancement of photogenerated charge carriers is observed in the nanorods in comparison to pristine C₆₀, revealing the effect of shape on the photovoltaic properties. Due to their ultrarapid, large-scale, room-temperature synthesis with single-crystalline structure and excellent optoelectronic properties, the nanorods are expected to be promising for photosensitive devices applications

Antibacterial Effect of Silver-Incorporated Flake-Shell Nanoparticles under Dual-Modality

Silver has been recognized as a broad-spectrum antimicrobial agent and extensively used in biomedical applications. Through a sequential one-pot synthesis strategy, we have successfully incorporated silver into flake-shell nanoparticles. Due to the simultaneous growth of networked nanostructures of silica and in situ reduction of silver ions, homogeneously distributed silver into the shell of the nanocapsule was formed. The antibacterial test indicated that the silver-incorporated silica nanocapsule exhibits effective antibacterial activity, inhibiting the bacterial growth by 75%. In addition, with the encapsulation of other antibiotic agent into the structure, an enhanced antibacterial effect under dual-modality could also be achieved

Fullerene Crystals with Bimodal Pore Architectures Consisting of Macropores and Mesopores

A new class of fullerene (C₆₀) crystals with bimodal pore architectures consisting of macropores and mesopores was synthesized by using a liquid–liquid interfacial precipitation (LLIP) method involving an interface between isopropyl alcohol (IPA) and a saturated solution of C₆₀ in a mixture of benzene and carbon tetrachloride (CCl₄). By varying the mixing fraction of CCl₄ in benzene, the porosity and electrochemically active surface area can be flexibly controlled

Surfactant-Triggered Nanoarchitectonics of Fullerene C₆₀ Crystals at a Liquid–Liquid Interface

Here, we report the structural and morphological modulation of fullerene C₆₀ crystals induced by nonionic surfactants diglycerol monolaurate (C₁₂G₂) and monomyristate (C₁₄G₂). C₆₀ crystals synthesized at a liquid–liquid interface comprising isopropyl alcohol (IPA) and a saturated solution of C₆₀ in ethylbenzene (EB) exhibited a one-dimensional (1D) morphology with well-defined faceted structure. Average length and diameter of the faceted rods were ca. 4.8 μm and 747 nm, respectively. Powder X-ray diffraction pattern (pXRD) confirmed a hexagonal-close packed (<i>hcp</i>) structure with cell dimensions ca. <i>a</i> = 2.394 nm and <i>c</i> = 1.388 nm. The 1D rod morphology of C₆₀ crystals was transformed into “Konpeito candy-like” crystals (average diameter ca. 1.2 μm) when the C₆₀ crystals were grown in the presence of C₁₂G₂ or C₁₄G₂ surfactant (1%) in EB. The pXRD spectra of “Konpeito-like” crystals could be assigned to the face-centered cubic (<i>fcc</i>) phase with cell dimensions ca. <i>a</i> = 1.4309 nm (for C₁₂G₂) and <i>a</i> = 1.4318 nm (for C₁₄G₂). However, clusters or aggregates of C₆₀ lacking a uniform morphology were observed at lower surfactant concentrations (0.1%), although these crystals exhibited an <i>fcc</i> crystal structure. The self-assembled 1D faceted C₆₀ crystals and “Konpeito-like” C₆₀ crystals exhibited intense photoluminescence (PL) (∼35 times greater than pC₆₀) and a blue-shifted PL intensity maximum (∼15 nm) compared to those of pC₆₀, demonstrating the potential use of this method for the control of the optoelectronic properties of fullerene nanostructures. The “Konpeito-like” crystals were transformed into high surface area nanoporous carbon with a graphitic microstructure upon heat-treatment at 2000 °C. The heat-treated samples showed enhanced electrochemical supercapacitance performance (specific capacitance is ca. 175 F g^–1, which is about 20 times greater than pC₆₀) with long cyclic stability demonstrating the potential of the materials in supercapacitor device fabrication

Hierarchically Structured Fullerene C₇₀ Cube for Sensing Volatile Aromatic Solvent Vapors

We report the preparation of hierarchically structured fullerene C₇₀ cubes (HFC) composed of mesoporous C₇₀ nanorods with crystalline pore walls. Highly crystalline cubic shape C₇₀ crystals (FC) were grown at a liquid–liquid interface formed between <i>tert</i>-butyl alcohol and C₇₀ solution in mesitylene. HFCs were then prepared by washing with isopropanol of the FC at 25 °C. The growth directions and diameters of C₇₀ nanorods could be controlled by varying washing conditions. HFCs perform as an excellent sensing system for vapor-phase aromatic solvents due to their easy diffusion through the mesoporous architecture and strong π–π interactions with the sp² carbon-rich pore walls. Moreover, HFCs offer an enhanced electrochemically active surface area resulting in an energy storage capacity 1 order of magnitude greater than pristine C₇₀ and fullerene C₇₀ cubes not containing mesoporous nanorods

Totally Phospholipidic Mesoporous Particles

Medical science is one of the areas where mesoporous materials can offer important advances despite the stringent safety requirements for potentially useful materials. Here we report totally phospholipidic mesoporous particles which may be used as a novel drug carrier. This material is anticipated to be safe for human internal use since it is composed solely of phosphatidylcholine (PC) which is a major component of biological membranes and is approved for use in humans by the US Food and Drug Administration (FDA). We have established a simple production methodology of mesoporous phospholipid particles (MPPs) in which PC is dissolved in two-component solvent mixtures, followed by incubation of the resulting solutions at depressed temperatures, which induces liquid–liquid demixing and leads to the agglomeration of PC as spherical particles. A mesoporous form was then obtained by removing ice crystals through freeze-drying of the particles. MPP could accommodate both hydrophilic and hydrophobic guest molecules in the lamellar structure and the mesopores. It might be applied as a novel drug carrier in a complementary or even a replacement technology of liposomes

Interaction of vascular endothelial cells with hydrophilic fullerene nanoarchitectured structures in 2D and 3D environments

The interaction between diverse nanoarchitectured fullerenes and cells is crucial for biomedical applications. Here, we detailed the preparation of hydrophilic self-assembled fullerenes by the liquid-liquid interfacial precipitation (LLIP) method and hydrophilic coating of the materials as a possible vascularization strategy. The interactions of vascular endothelial cells (ECs) with hydrophilic fullerene nanotubes (FNT-P) and hydrophilic fullerene nanowhiskers (FNW-P) were investigated. The average length and diameter of FNT-P were 16 ± 2 μm and 3.4 ± 0.4 μm (i.e. aspect ratios of 4.6), respectively. The average length and diameter of FNW-P were 65 ± 8 μm and 1.2 ± 0.2 μm (i.e. aspect ratios of 53.9), respectively. For two-dimensional (2D) culture after 7 days, the ECs remained viable and proliferated up to ~ 420% and ~ 400% with FNT-P and FNW-P of 50 μg/mL, respectively. Furthermore, an optimized chitosan-based self-healing hydrogel with a modulus of ~400 Pa was developed and used to incorporate self-assembled fullerenes as in vitro three-dimensional (3D) platforms to investigate the impact of FNT-P and FNW-P on ECs within a 3D environment. The addition of FNW-P or FNT-P (50 μg/mL) in the hydrogel system led to proliferation rates of ECs up to ~323% and ~280%, respectively, after 7 days of culture. The ECs in FNW-P hydrogel displayed an elongated shape with aligned morphology, while those in FNT-P hydrogel exhibited a rounded and clustered distribution. Vascular-related gene expressions of ECs were significantly upregulated through interactions with these fullerenes. Thus, the combined use of different nanoarchitectured self-assembled fullerenes and self-healing hydrogels may offer environmental cues influencing EC development in a 3D biomimetic microenvironment, holding promise for advancing vascularization strategy in tissue engineering. Self-assembled fullerenes with large aspect ratios modulate the morphology and gene expression of endothelial cells within a soft biomimetic 3D microenvironment, representing a promising new vascularization strategy in tissue engineering.</p

Quasi 2D Mesoporous Carbon Microbelts Derived from Fullerene Crystals as an Electrode Material for Electrochemical Supercapacitors

Fullerene C₆₀ microbelts were fabricated using the liquid–liquid interfacial precipitation method and converted into quasi 2D mesoporous carbon microbelts by heat treatment at elevated temperatures of 900 and 2000 °C. The carbon microbelts obtained by heat treatment of fullerene C₆₀ microbelts at 900 °C showed excellent electrochemical supercapacitive performance, exhibiting high specific capacitances ca. 360 F g^–1 (at 5 mV s^–1) and 290 F g^–1 (at 1 A g^–1) because of the enhanced surface area and the robust mesoporous framework structure. Additionally, the heat-treated carbon microbelt showed good rate performance, retaining 49% of capacitance at a high scan rate of 10 A g^–1. The carbon belts exhibit super cyclic stability. Capacity loss was not observed even after 10 000 charge/discharge cycles. These results demonstrate that the quasi 2D mesoporous carbon microbelts derived from a π-electron-rich carbon source, fullerene C₆₀ crystals, could be used as a new candidate material for electrochemical supercapacitor applications