This review describes the state-of-the-art scientific developments of bolaamphiphilic molecules composed of two hydrophilic headgroups connected by a hydrophobic chain in the middle of the molecule. In contrast to previous review articles, this review focuses on the discussion of the bolaamphiphilic molecules from assembly to applications in various fields. The main principles of the assembly structures of bolaamphiphilic molecules are discussed, both at interfaces, including air/water and liquid/solid, and in solutions. Since different interactions exist among hydrophilic or polar head groups of the molecules, and the complexity of different hydrophobic, van der Waals, π–π interactions, etc., between the chains, the assembly structures of the bolaamphiphilic molecules in the solution are more complicated and are therefore discussed in more detail. Finally, current applications for several important structures and assembly mechanisms of the molecules are introduced.

In this review, the main concept of ferroelectricity of perovskite oxides and related materials at nanometer scale and existing difficulties in the synthesis of those nanocrystals are discussed. Important effects, such as depolarization field and size effect, on the existence of ferroelectricity in perovskite nanocrystals are deliberated. In the discussion of modeling works, different theoretical calculations are pinpointed focusing on their studies of lattice dynamics, phase transitions, new origin of ferroelectricity in nanostructures, etc. As the major part of this review, recent research progress in the facile synthesis, characterization and various applications of perovskite ferroelectric nanomaterials, such as BaTiO₃, PbTiO₃, PbZrO₃, and BiFeO₃, are also scrutinized. Perspectives concerning the future direction of ferroelectric nanomaterials research and its potential applications in renewable energy, etc., are presented. This review provides an overview in this area and guidance for further studies in perovskite ferroelectric nanomaterials and their applications.

Aqueous phospholipid mixtures that form bilayered micelles (bicelles) have gained wide use by molecular biophysicists during the past 20 years for spectroscopic studies of membrane-bound peptides and structural refinement of soluble protein structures. Nonetheless, the utility of bicelle systems may be compromised by considerations of cost, chemical stability, and preservation of the bicelle aggregate organization under a broad range of temperature, concentration, pH, and ionic strength conditions. In the current work, 31P nuclear magnetic resonance (NMR) and atomic force microscopy (AFM) have been used to monitor the size and morphology of isotropically tumbling small bicelles formed by mixtures of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) or 1,2-di-O-tetradecyl-sn-glycero-3-phosphocholine (DIOMPC) with either 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC) or 1,2-di-O-hexyl-sn-glycero-3-phosphocholine (DIOHPC), testing their tolerance of variations in commonly used experimental conditions. 1H-15N 2D NMR has been used to demonstrate the usefulness of the robust DMPC–DIOHPC system for conformational studies of a fatty acid-binding protein that shuttles small ligands to and from biological membranes.

Multiferroics represent a class of new materials having potential applications for design and preparation of multifunctional material due to the possibility of the coupling of their coexisting electric and magnetic orderings. The magnetic polarization can be switched by applying an electric field; and the electric polarization, by applying a magnetic field. We report here our attempts using three approaches for fabricating multiferroic ferrites: autoclave, microemulsion and spin-casting. All three methods are based on a precursor solution prepared by dissolving stoichiometric amount of bismuth(III) nitrate and iron(III) nitrate in ethylene glycol. In the autoclave synthesis, sodium hydroxide and hydrogen peroxide were dissolved in DI water with surfactant (Triton x-100, Tx-100) and then the precursor solution was added. The solution was transferred to an autoclave at either 165 or 185 °C for reaction for 24 hours. The two temperatures led to two different bismuth ferrite nanocrystals, Bi 2 Fe 4 O 9 (165 °C) and BiFeO 3 (185 °C). For microemulsion synthesis, sodium hydroxide and hydrogen peroxide were dissolved in DI water and added to an oil solution (cyclohexane and n-butanol) with added surfactant, Tx-100, as “Emulsion I”. “Emulsion II” was made by adding precursor in an oil solution (cyclohexane and n-butanol). “Emulsion I” was allowed to react with “emulsion II” at 80 °C for 3 hours. A non-crystalline bismuth ferrite with a 1:1 atomic ratio for Bi∶ Fe was obtained. The spin-casting method produced the BiFeO 3 (BFO) thin film with the desired quality. The quality of the resulting BFO thin film depended strongly on the spinning rates and annealing temperatures. The morphology of all samples was studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). X-ray dispersive spectroscopy (EDS) was used to confirm the elemental composition in bismuth ferrite samples. X-ray diffraction (XRD) was used for establishing crystalline structures.

Single crystalline nanoneedles of three families of the most studied conductive organic polymers - polythiophene, polyaniline and polypyrrole - were synthesized for the first time using an interfacial polymerization process that takes place with simultaneous crystallization. As the crystal growth is concurrent with polymerization, more ordered crystal packing can be expected. Most of the bulk conducting-polymer systems studied contains regions that are inhomogeneous. Single nanocrystals of conducting polymers have not been reported, although needle-shaped bulk crystals of the quarterphenyl cation radical salt have previously been studied. The investigation of processes in a nanodomain of a single crystal is critical in ascertaining the inherent electronic properties of polymer nanoelements. The organic conductive nanoneedles were characterized using TEM, HRTEM, electron diffraction, EDS, and EPR to establish their crystal structure and composition. Scanning tunneling microscopy/spectroscopy (STM/STS) investigation were conducted to examine their electronic behaviors, leading to the discovery of a field-induced conductance switching with response times on the millisecond level. The switch voltages are in the range of 3 to 4 volts in STM experiments, consistent with the trend of the band gap of the three polymers. The organic conductive nanoneedles with nano-tip having high density of mobile electron may serve as interesting elements for nanoscale electronics.

Single crystalline nanoneedles of polyaniline (PANI) and polypyrrole (PPY) were synthesized using an interfacial polymerization for the first time. The interfacial crystallization of conductive polymers at the liquid/liquid interface allowed PANI and PPY polymers to form single crystalline nanocrystals in a rice-like shape in the dimensions of 63 nm x 12 nm for PANI and 70 nm x 20 nm for PPY. Those crystalline nanoneedles displayed a fast conductance switching in the time scale of milliseconds. An important growth condition necessary to yield highly crystalline conductive polymers was the extended crystallization time at the liquid/liquid interfaces to increase the degree of crystallization. As compared to other interfacial polymerization methods, lower concentrations of monomer and oxidant solutions were employed to further extend the crystallization time. While other interfacial growth of conducting polymers yielded noncrystalline polymer fibers, our interfacial method produced single crystalline nanocrystals of conductive polymers. We recently reported the liquid/liquid interfacial synthesis of conducting PEDOT nanocrystals; however, this liquid/liquid interfacial method needs to be extended to other conductive polymer nanocrystal syntheses in order to demonstrate that our technique could be applied as the general fabrication procedure for the single crystalline conducting polymer growth. In this report, we showed that the liquid/liquid interfacial crystallization could yield PANI nanocrystals and PPY nanocrystals, other important conductive polymers, in addition to PEDOT nanocrystals. The resulting crystalline polymers have a fast conductance switching time between the insulating and conducting states on the order of milliseconds. This technique will be useful to synthesize conducting polymers via oxidative coupling processes in a single crystal state, which is extremely difficult to achieve by other synthetic methods.

The present invention is directed to perovskite nanostructures of Formula ABO, wherein A and B represent one or more metals with A having a valence lower than B, to methods of making the perovskite nanostructures of Formula ABOcomprising their synthesis within and precipitation from reverse micelles, and the use of the perovskite nanostructures of Formula ABOas capacitors, and their use in dynamic random access memory, electromechanics, and non-linear optics.

The shape of silica nanoparticles is controlled when they are synthesized at liquid/liquid interfaces; the combination of organic and aqueous phases that form the interface can change the shape of silica into a triangle, cube, or rod.

The preparation of PEDOT single-crystal nanoneedles using an interfacial polymerization process with simultaneous crystallization is reported. The absence of external dopants and crystallization during chain growth leads to closely packed crystals. These nanoneedles show a novel switching behavior with a response time in milliseconds (see figure).

In this letter, we report the first facile open-bench synthesis of BaTiO3, SrTiO3 nanocrystals, and their nanosolid solutions BaxSr1-xTiO3 (BST) at 80 degrees C. The size of the BST nanoparticles was readily tuned from similar to 50 to similar to 10 nm with achievable giant dielectric constants. The process yielded these important perovskite mixed-metal oxide crystals of high quality on the nanometer scale without a history of thermal stress. This new synthesis system involves inorganic starting materials without organic components and does not require demanding conditions such as an inert environment, high pressure, and high temperature.

The peptide nano-rings containing Au nanoparticles inside their cavities were self-assembled on dithiol SAMs patterned as an array by AFM-based nanolithography. The peptide nano-rings were aligned as a line on these SAMs, and Au formed lines with the spacing between these nanoparticles as the peptide nano-rings functioned as spacers. This type of array fabrication will provide improved tunability in their optical properties of resulting nanoparticle-assembled arrays. In addition, optimization of the inter-particle distance of nanoparticles in the array with various spacers may allow one to design new types of photonic crystals with desired optical properties.

Tetragonal ferroelectric BaTiO3 nanoparticles are hydrolyzed inside peptide-ring templates at room temperature and pressure (see figure). The sizes of the monodisperse BaTiO3 nanoparticles are controlled between 6 and 12 run by varying the cavity size of the nanorings as a function of pH. The nanoparticles possess switching behavior under the influence of external electric fields.