Multifunctional Langmuir-Blodgett film of an Amphiphilic Benziminazole Styryl Dye

An amphiphilic benziminazole styryl dye, 2 (4 dihexadecylaminostyryl)benziminazolium TCNQ -(DBTCNQ), was synthesized and successfully transferred onto the substrates by Langmuir Blodgett(LB) technique. H aggregates were formed on the substrates. Its monolayer second order susceptibility[ χ (2) zzz = 109 p/mV) was determined with a polarized laser beam(Nd∶YAG, λ =1.064 μm). The photoelectrochemistry of the dye LB monolayer films was investigated in a traditional three electrode cell. The quantum efficiency of photoelectric conversion is 1.08% under favorable conditions [-200 mV, 0.5 mg/mL methylviologen diiodide(MV 2+ ) in 0.5 mol/L KCl electrolyte solution]. The experimental data indicate that the LB film exhibits multifunctional properties.

Langmuir-Blodgett Films and Calcium Ion Coordination of Biliverdin and Its Amphiphilic Derivatives

Monolayer formation and LB film fabrication of amphiphilic derivative of biliverdin 1, diododecyl biliverdinamide [B（CONHC12H25）2, 2] at an air-water interface on pure water subphase and subphase containing calcium ion were investigated and compared with 1. The coordination in ordered molecular films is much different from that in bulk solution. The formation of ligand-calcium complex was confirmed by X-ray photoelectron spectroscopy.

Synthesis and Langmuir-Blodgett Film Analysis of Atropisomers of “Picket Fence” Porphyrin

Four "picket fence" porphyrin atropisomers were respectively synthesized from the four corresponding atropisomers of meso-tetra(o-aminophenyl)porphyrin that had been chromatographed on a column eluted with petro-leum ether and ethyl acetate. Results show that each atropisomer could be successfully synthesized by controlling the acylation temperature at 0 °C. They were characterized by 1 H NMR, HRMS, IR, UV-Vis and Langmuir-Blodgett(LB) film analyses. Although the results of HRMS, IR, UV-Vis analyses indicate there is no remarkable difference among the atropisomers, the results of the 1 H NMR and the mean molecular areas obtained by LB film technique imply that the atropisomers are significantly discrepant. The former shows that the chemical shifts of the methyl and amide protons of each atropisomer are distinct, while the later presents that the different atropisomer molecules can occupy the different surface areas at the air/water interface.

Nanoscale Hybrid Langmuir-Blodgett Films Based on Cerium-Substituted Heteropolymolybdate and Polyquinoline

Nanoscale hybrid organic/inorganic Langmuir-Blodgett films of cerium-substituted heteropolymolybdates(Ce-HPMo) and π-conjugated macromolecule poly(1,2-dihydro-2,2,4-trimethyl)quinoline(PQ) were obtained with auxiliary film-forming material stearic acid(SA) or octadecylamine(ODA). The surface pressure-area isotherms illuminate the formation of the hybrid LB films of PQ/ODA/Ce-HPMo and PQ/SA/Ce-HPMo. The different film-forming mechanism was discussed when the different auxiliary film-forming materials were used in the system. The absorption spectra indicate that the molecules of PQ and Ce-HPMo are incorporated into the LB films. Tapping-mode AFM image reveals a granular surface texture of nanosized Ce-substituted heteropolymolybdate. STM image shows that the conductivity is greatly improved after Ce-substituted heteropolymolybdates are incorporated in the films.

Monolayers Langmuir-Blodgett Films of Synthetic Artificial Mimic Molecules That Resemble the Following Tetraether Lipids on Silicon Wafers

This study investigated the behavior and molecular organization of synthetic artificial mimic molecules that resemble the following tetraether lipids: di-O-hexadecyl-glycero-3-phosphatidyl-glycerol (DHGPG) and bis-4-dodecylphenyl-12-phosphate. These molecules were analyzed using Langmuir film balance, ellipsometry and atomic force microscopy. The monolayer Langmuir-Blodgett films of DHGPG and bis-4-dodecylphenyl-12-phosphate were stable on the solid surface silicon wafers. The ellipsometry and AFM results showed that monolayers Langmuir-Blodgett films of DHGPG and bis-4-dodecylphenyl-12-phosphate were present, and the thickness of the observed films varied from 1.2 - 5.0 nm.

Langmuir-Blodgett Films from Schiff Base Aluminium (Ⅲ) Complex

The characteristics of the LB films of Schiff base aluminium( Ⅲ ), tris(2-hydroxy-5-nitro N-dodecyl-benzylideneaminato) aluminium ( Ⅲ ) [Al (TA 12) 3], were studied. The surface pres sure-area(r-A) isotherm of Al(TA12)3 in the pure water subphase was investigated. The molec ular area, 0.48 nm2, is one-third of the expected value that indicates the formation of an aggre gate. The Langmuir-Blodgett (LB) films of Al(TA12) 3 were transferred and characterized. The UV-Vis spectra and the AFM image both confirmed that the J-aggregates formed. The polarized UV-Vis spectra indicated that the complex plane had to be oriented with an angle of about 30° to the substrate surface. The IR spectra suggested that the complexation took place between aluminium ions and the oxygen atoms of the ligand rather than the nitrogen atom.

CHARACTERIZATION AND LUMINESCENCE PROPERTIES OF THE DYE-DOPED POLYMER LANGMUIR-BLODGETT FILMS

1,1,4,4-Tetraphenyl-1,3-butadiene (TPB) was successfully introduced into the polymer multilayerfilms by means of Langmuir-Blodgett (LB) technique. Results of UV-VIS spectra and X-ray diffractionshowed that the uniform films had a layer structure similar to the superlattice of organic multiple quantumwells. The electroluminescence (EL) devices fabricated from the doped polymer LB films emitted blue light.Compared with the casting films, the photoluminescence (PL) and EL spectra showed that the exciton energyshifts to higher and the half-width of the emission peak becomes narrower due to exciton confinement effect.

Formation of ring calcium oxalate patterns induced by domains in DPPC Langmuir-Blodgett films

The ring patterns of calcium oxalate crystals were induced by domains in Langmuir-Blodgett (LB) films of dipalmitoylpho-sphatidylcholine (DPPC). The result was explained by the defects at the ring boundaries of liquid condensed (LC) and liquid expanded (LE) phases of LB film. These boundaries could provide less free energy and much more nucleating sites for COM crystals.

Preparation of Langmuir-Blodgett Film of Oligophenylenevinylene at the Air/Water Interface and Study on its Fluorescence

Methoxy groups is favorable for film-forming property of oligophenylenevinylenes(OPVs) and the Langmuir-Blodgett film of 1,4-bis (3,4,5-trimethoxystyryl)-2,5-dimethoxybenzene(MOPV) was prepared. It might be the formation of H-aggregate of MOPV in the LB film thatresults in a 57 nm blue shift of λmax for the absorption and a 58 nm red shift of λmax for thefluorescence, respectively.

POLYMETHYLMETHACRYLATE LANGMUIR-BLODGETT FILMS FOR HIGH RESOLUTION ELECTRON BEAM RESIST

Ultra-thin (20-100nm) polymethylmethacrylate(PMMA) films prepared by Langmuir-Blodgett techniques have been explored as high resolution electron beam resists. A Hitachi S-450 Scanning Electron Microscope (SEM) has been refitted for a high resolution electron beam exposure system. The lithographic properties and exposure conditions of LB PMMA films were investigated. 0.15μm lines-and-spaces patterns were achieved by using the SEM as the exposure tool. The results demonstrate that the etch resistance of such films is sufficiently good to allow patterning of a 20 nm aluminum film suitable for mask fabrication.

Preparation and Characteristics of Stearic Acid/PEDOT(PSS) Langmuir-Blodgett Films

Mixed Stearic acid and poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (PEDOT/PSS) Langmuir- Blodgett(LB) films were successfully fabricated by the conventional vertical dipping method.Stearic acid and PEDOT/PSS was dissolved in chloroform and spread on subphase containing 0.04wt% FeCl_3.Conductive Y-type mixed LB films was successfully prepared under the condition of surface pressure with 30 mN/m,pH 3.8,and 19℃.UV-VIS spectrum showed that well ordered layer-by-layer fabrication of mixed films were obtained and thickness of single layer film with about 5 nm was evaluated.The morphology image of mixed LB film was observed by atomic force microscopy (AFM).The conductivity of mixed LB film was about 1.8×10^(-5)S/cm and the film showed sensitivity to NH_3 at the same time.

Fabrication and structure of Langmuir-Blodgett films of ferroelectric liquid crystal

The molecular aggregation, orientation, and structure in Langmuir-Blodgett films of ferroelectric liquid crystal were studied by ultraviolet and Fourier transform infrared spectra. The results show that medium strong (H-aggregates) in the Langmuir-Blodgett films of ferroelectric liquid crystal are formed by chromophores where the alkyl chains are nearly perpendicular to the film surface. Compared with the cast films, the CO stretching bands, due to the rotational isomerism around the O—C axis of the chiral part, can be identified clearly in Langmuir-Blodgett films.

Preparation of Dithienylethene with Amino Groups, and Photochromic Behavior in Langmuir-Blodgett Film of the Amphiphilicdithienylethene

We successfully synthesized dithienylethene with amino groups. Then, we successfully prepared Langmuir-Blodgett (LB) films of the dithienylethene having ammonium cation group when dodecyl benzene sulfonic acid was employed as an anionic counter ion. From X-ray diffraction profiles, however, it was demonstrated that they did not form well-defined layered structure;X-ray diffraction peaks were much broadened. Photochromic behavior was confirmed in the LB films. Unfortunately, the LB films were not so stable;photochromic reaction was observed only several times in the LB films.

Coordination Interaction between Rare Earth and/or Transition Metal Centers and Thiophene Series Oligomer Derivatives in Ultrathin Langmuir-Blodgett Films

It has been shown by thermodynamic and electro-chemical methods that coordination interactions are involved in the process of incorporation of rare-earth elements and/or Fe into Langmuir monolayers of oligomer with alkyl fragment. A coordination mechanism, which is responsible for self-organization of octahedral Fe(II)-complexes of nano-cyclic ligands obtained from oligomer of thiophene pyrrole series derivatives in compressed Langmuir monolayers has been proposed. It has been established that a coordinational-polymeric hexagonal network of nano-cyclic ligands with metal centers is formed at the phase transition when compressing the Langmuir monolayers of thiophene pyrrole series oligomer with alkyl fragment on surface of subphase with rare-earth (Sm, Er, Ce) and/or Fe ions.

Regeneration of Q-State PbS Particles in Langmuir-Blodgett Films

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Polarization of Hemicyanine Langmuir-Blodgett Films

The polarization dependence of electric field for hemicyanine layers deposited by the Langmuir-Blodgett (LB) technique has been measured. The experimental results show that ferroelectricity exists not only in thick films (200nm) but also in thinner films (3Ohm), and the remnant polarization is related to film thickness. In order to interpret the measured results, a planar rotor model was introduced, and a relation between polarization and film thickness was obtained by perturbation theory. The theory fitting agrees with experimental results well. It is confirmed that ferroelectricity in organic molecular LB films mainly arose from altering of molecular orientation.

Surface-Enhanced Resonance Raman Spectra of Langmuir-Blodgett Films of Tetra-Lauryl Chloroaluminum Phthalocyanine

The Langmuir-Blodgett(LB)films of tetra-lauryl chloroaluminum phthalocyanine(TLAlCIPc)and a 1:1 mixture of TLAlCIPc and stearyl alcohol(SA)were prepared.The Raman spectrum of solid TLAlCIPc in KBr pellet was investigated.All the Raman lines were assigned.The surface-enhanced resonance Raman spectra of the LB films deposited on the silver island film that were vacuum-deposited on glass slides have been observed.

Interlayer Energy Transfer from Naphthalene to Anthracene Chromophores Organized in Langmuir-Blodgett Films

Interlayer energy transfer between 2, 3-naphtho-10-hexadecylaza-15-crown-5 (NC16) and N-[1-(9-methoxyanthryl)]decylaza-15-crown-5 (A10C) within multilayer Langmuir-Blodgett films has been studied by steady-state fluorescence spectra. The donor and acceptor could be separated precisely by inserting stearic acid (SA) spacers. The efficiency of the energy transfer increases with the decrease in the donor-acceptor distance by a quadratic manner, suggesting the donor excitations are delocalized in the layer.

Interfacial Behaviors of Azocalixarene Derivatives at the Air/Water Interface and Photochromism in the Langmuir-Blodgett Films

The interfacial behaviors of the non-typical amphiphilic compound p-methylphenylazo- calix[4]arene 1 and p-chlorophenylazocalix[4]arene 2 at the air/water interface and photo- chromism in the Langmuir-Blodgett films were studied by surface pressure-area isotherm and UV-Vis spectra. The results indicate that they can form stable monolayers at the air / water interface although they have no hydrophobic alkyl chains, and their LB film underwent reversible trans-cis photoisomerization on UV and daylight illumination.

Ultrathin Limit on the Anisotropic Superconductivity of Single-Layered Cuprate Films

Exploring dimensionality effects on cuprates is important for understanding the nature of high-temperature superconductivity.By atomically layer-by-layer growth with oxide molecular beam epitaxy,we demonstrate that La_(2−x)Sr_(x)CuO_(4)(x=0.15)thin films remain superconducting down to 2 unit cells of thickness but quickly reach the maximum superconducting transition temperature at and above 4 unit cells.By fitting the critical magnetic field(μ0H_(c2)),we show that the anisotropy of the film’s superconductivity increases with decreasing film thickness,indicating that the superconductivity of the film gradually evolves from weak three-to two-dimensional character.These results are helpful to gain more insight into the nature of high-temperature superconductivity with dimensionality.