Liposomes from α,ω-dipolar amphiphiles with a polymerizable diyne moiety in the hydrophobic chain

Symmetric polymerizable α,ω-dipolar C₂₂-diacetylenes were prepared by oxidative coupling of 10-undecynoic acid and 10-undecynol, respectively, by means of copper II salts in ethanolic solution. 10,12-Docosadiyne-1,22-diphosphate ( 3 )—by reaction of 10,12-docosadiyne-1,22-diol ( 2 ) with POCl₃—was polymerized in aqueous solution using UV irradiation to form deep blue, thermochromic solutions. By consonication of 3 with cholesterol, monolayer vesicles were formed. This was proven by encapsulation of 6-carboxyfluorescein. These monomeric vesicles were polymerized by UV light to yield stable, deep blue polymeric vesicle suspensions.     

Enantioselective recognition between polydiacetylene nucleolipid monolayers and complementary oligonucleotides

A two-dimensional bio/synthetic hybrid system at the air-solution interface made of a polymerized diacetylene Langmuir film with nucleobase modified headgroups is presented. The polymerized film presents a crystalline array of nucleobases, capable of specific binding of complementary mononucleoside or oligonucleotide sequences. Mixed monolayers of the linear polyconjugated polydiacetylene (PDA) films derivatized with cytosine (10,12-pentacosadiyne-cytidyl, PDC) monomers and alcohol-terminated diacetylene lipid (10,12-pentacosadiynol, PDOH) at a 3:1 ratio (PDC 75%) were compressed and polymerized at the air-water interface with circular polarized light (CPL) or nonpolarized UV light. Here we report a grazing incidence X-ray diffraction (GIXD) investigation of PDC films polymerized to different chirality and hybridized with complementary ssDNA strands. We have demonstrated enantioselective interactions on synthetic structured interfaces produced by Langmuir surface compression followed by polymerization with circular polarized UV light (CPL). The left- and right-CPL polymerized light exhibit the same well-defined crystalline structure. The observed difference between left- and right-CPL polymerized PDC 75% Langmuir films compressed over the complementary mononucleotide guanosine or hybridized with fully complementary ssG(12)T(5) oligonucleotide in the subphase suggests that they are indeed enantiomeric structures, capable of enantioselective binding of their natural ligand, guanosine, solely as a result of surface induced asymmetry in "left" but not in "right" form. This observation may also be related to the intriguing question of chiral selection during the early period of "Origin of Life". We show that achiral compounds, as a result of irradiation with circular polarized light, can organize in chiral surface structures capable of amplification of biopolymer binding of particular handedness.     

Photopolymerization of mixed monolayers and black lipid membranes containing gramicidin A and diacetylenic phospholipids

We formed monolayers and black lipid membranes (BLMs) of photopolymerizable lipids mixed with the channel-forming protein gramicidin A to evaluate their miscibility and the potential for improved stability of the BLM scaffold through polymerization. Analyses of surface pressure vs area isotherms indicated that gramicidin A dispersed with three different synthetic, polymerizable, diacetylene-containing phospholipids, 1,2-di-10,12-tricosadiynoyl-sn-glycero-3-phosphocholine (DTPC), 1,2-di-10,12-tricosadiynoyl-sn-glycero-3-phosphoethanolamine (DTPE), and 1-palmitoyl-2,10,12-tricosadiynoyl-sn-glycero-3-phosphoethanolamine (PTPE) to form mixed monolayers at the air-water interface on a Langmuir-Blodgett (LB) trough. Conductance measurements across a diacetylenic lipid-containing BLM confirmed dispersion of the gramicidin channel with the lipid layer and demonstrated gramicidin ion-channel activity before and after UV exposure. Polymerization kinetics of the diacetylenic films were monitored by film pressure changes at constant LB trough area and by UV-vis absorption spectroscopy of polymerized monolayers deposited onto quartz. An initial increase in film pressure of both the pure diacetylene lipid monolayers and mixed films upon exposure to UV light indicated a change in the film structure. Over the time scale of the pressure increase, an absorbance peak indicative of polymerization evolved, suggesting that the structural change in the lipid monolayer was due to polymerization. Film pressure and absorbance kinetics also revealed degradation of the polymerized chains at long exposure times, indicating an optimum time of UV irradiation for maximized polymerization in the lipid layer. Accordingly, exposure of polymerizable lipid-containing black lipid membranes to short increments of UV light led to an increase in the bilayer lifetime.     

双炔酸多层LB膜的光敏聚合研究

选用(口恶)花菁染料为光敏剂,将其镶嵌到双炔酸LB膜中,利用Ar~+离子激光514.5 nm照射LB膜,观察到双炔酸LB膜的光敏聚合及(口恶)花菁染料荧光的猝灭,对其光敏聚合机理进行了讨论。     

Deposition and photopolymerization of phase-separated perfluorotetradecanoic acid-10,12-pentacosadiynoic acid Langmuir-Blodgett monolayer films

Mixed monolayer surfactant films of perfluorotetradecanoic acid and the photopolymerizable diacetylene molecule 10,12-pentacosadiynoic acid were prepared at the air-water interface and transferred onto solid supports via Langmuir-Blodgett (LB) deposition. The addition of the perfluoroacid to the diacetylene surfactant results in enhanced stabilization of the monolayer in comparison with the pure diacetylene alone, allowing film transfer onto a solid substrate without resorting to addition of cations in the subphase or photopolymerization prior to deposition. The resulting LB films consisted of well-defined phase-separated domains of the two film components, and the films were characterized by a combination of atomic force microscope (AFM) imaging and fluorescence emission microscopy both before and after photopolymerization into the highly emissive "red form" of the polydiacetylene. Photopolymerization of the monolayer films resulted in the formation of diacetylene bilayers, which were highly fluorescent, with the apparent rate of photopolymerization and the fluorescence emission of the films being largely unaffected by the presence of the perfluoroacid.     

Nucleobase Derived Monolayers of Conjugated Polymers for Nucleotide Recognition

Polymerizable amphiphilic diacetylene containing monomers, (10,12 pentacosadinoyic acid, PDA) with a cytosine derived headgroup were synthesized and spread on a Langmuir film balance. Various surface dilutions of the cytosine and alcohol derivatives (PDC and PDOH, respectively) were produced and UV polymerized in situ. Films were produced in water and in a solution containing the complementary base (guanosine, G). Each dilution exhibited typical features in its compression isotherm, visible spectra, and structural organization when examined by Brewster angle microscopy, polarized light microscopy and SPM.     

Optical properties of thermally evaporated 4-(4-nitrobenzalideneamino) antipyrine Schiff base thin films

4-(4-nitrobenzalideneamino) antipyrine (NBAA) have been synthesized by refluxed ethanolic solution of 4-aminoantipyrine and p-nitrobenzaldehyde for 4 h and characterized with various physico-chemical techniques. Thin films of NBAA have been prepared by the thermal deposition technique in a vacuum of 1.5 × 10⁻⁵ mbar onto optical flat glass substrates. X-ray diffraction patterns show amorphous nature for all NBAA thin films except UV irradiated thin film which shows amorphous nature with some crystallinity but with small amount. The optical constants of thermally deposited NBAA thin film were investigated in the wavelength range 200–2500 nm. The type of optical transition near the edge of the band gap is found to be indirect allowed transition. The effect of UV irradiation as well as the effect of annealing on the optical properties of NBAA thin films was investigated. The value of the energy gap for thin films under investigation is calculated and found to be 1.56 eV for as-deposited, 1.45 eV for annealed and 1.82 eV for UV irradiation.     

(Ni-Mo)/TiO2纳米薄膜光催化降解刚果红的性能与机理

用恒电流复合电沉积方法制备(Ni-Mo)/TiO2薄膜,以扫描电子显微镜(SEM)、X射线衍射(XRD)、拉曼(Raman)光谱和紫外-可见漫反射光谱(UV-VisDRS)对薄膜的表面形貌、晶相结构和光谱特性进行了表征,以刚果红为模拟污染物对薄膜的光催化性能进行了测定,并讨论了刚果红溶液的pH值对薄膜光催化活性的影响.采用循环伏安技术和向溶液中加入活性物种捕获剂的方法对薄膜光催化降解机理进行了探索.结果表明:(Ni-Mo)/TiO2薄膜是由粒径为50-100nmTiO2纳米粒子相和纳米晶Ni-Mo固溶体相构成的复合薄膜.薄膜具有较高的光催化活性,卤钨灯照射80min后,复合薄膜光催化刚果红的降解率是多孔TiO2(DegussaP25)/ITO(氧化铟锡)纳米薄膜的2.43倍.(Ni-Mo)/TiO2薄膜光催化活性的提高主要归因于薄膜层中有效形成的(Ni-Mo)/TiO2异质结和良好的电子通道,以及Ni-Mo纳米晶合金对溶解氧和激发电子还原反应的催化作用.分别给出了在紫外和可见光下薄膜光催化降解刚果红的反应机理.     

Direct measurements of the mechanical properties of polymerized and unpolymerized langmuir-blodgett films

Mechanical measurements can be made on Langmuir-Blodgett (LB) films that have been peeled from their substrates, and are floating on the surface of water, by compressing them between the moving barrier and the Langmuir balance float in a standard monolayer trough. We have used this technique, which utilizes apparatus commonly available where LB films are made, to study multilayers of lead 10,12-tricosadiynoate (a diacetylene carboxylic acid) that were first polymerized and then peeled from the substrate. For comparison we have performed the same measurements on pieces of mylar, on unpolymerized films, and on films of calcium octadecanoate (a saturated chain fatty acid). We found Young's modulus for films of the saturated chain material, the unpolymerized diynoate, and the polymerized films, to be 6 GPa (900 kpsi), 0.5 GPa, and 6 GPa, respectively.     

Effect of sol temperature on the structure,morphology, optical and photoluminescence properties of nanocrystalline zirconia thin films

Transparent nanocrystalline zirconia thin films were prepared by sol–gel dip coating technique using Zirconium oxychloride octahydrate as source material on quartz substrates, keeping the sol at room temperature (SET I) and 60 °C (SET II). X-ray diffraction (XRD) pattern shows the formation of mixed phase [tetragonal (T) + monoclinic (M)] in SET I and a pure tetragonal phase in SET II ZrO₂ thin films annealed at 400 °C. Phase transformation from tetragonal to monoclinic was achieved in SET II film annealed at 500 °C. Atomic force microscopy analysis reveals lower rms roughness and skewness in SET II film annealed at 500 °C indicating better optical quality. The transmittance spectra gives a higher average transmittance >85% (UV–VIS region) in SET II films. Optical spectra indicate that the ZrO₂ films contain direct—band transitions. The sub- band in the monoclinic ZrO₂ films introduced interstitial O⁻defect states above the top of the valance band. The energy bandgap increased (5.57–5.74 eV) in SET I films and decreased (5.74–5.62 eV) in SET II films, with annealing temperature. This is associated with the variations in grain sizes. Photoluminescence (PL) spectra give intense band at 384 and 396 nm in SET I and SET II films, respectively. A twofold increase in the PL intensity is observed in SET II film. The “Red” shift of SET I films and “Blue” shift of SET II films with annealing temperature, originates from the change of stress of the film due to lattice distortions.     

Electroluminescence and Photoluminescence of Conjugated Polymer Films Prepared by Plasma Enhanced Chemical Vapor Deposition of Naphthalene

Polymer light-emitting devices were fabricated utilizing plasma polymerized thin films as emissive layers. These conjugated polymer films were prepared by RF plasma enhanced chemical vapor deposition using naphthalene as monomer. The effect of different applied powers on the chemical structure and optical properties of the conjugated polymers was investigated. Fourier transform infrared (FTIR) and Raman spectroscopies confirmed that a conjugated polymer film with a 3-D cross-linked network was developed. By increasing the power, products tended to form as highly cross-linked polymer films. The fabricated devices showed broadband Electroluminescence (EL) emission peaks with center at 535–550 nm. Photoluminescence (PL) spectra of plasma polymers showed different excimeric emissions, resulted from crosslinked architecture. As the plasma power increased, the optical properties showed two different domains; up to 200 W, EL, PL and UV–Vis spectra red-shifted and broadened significantly. At higher powers, a reverse behavior was observed. Also, the relation between the film structure and plasma species was investigated using optical emission spectroscopy.     

Synthesis and characterization of polydiacetylene films and nanotubes

We report here the synthesis and characterization of polydiacetylene (PDA) films and nanotubes using layer-by-layer (LBL) chemistry. 10,12-Docosadiyndioic acid (DCDA) monomer was self-assembled on flat surfaces and inside of nanoporous alumina templates. UV irradiation of DCDA provided polymerized-DCDA (PDCDA) films and nanotubes. We have used zirconium-carboxylate interlayer chemistry to synthesize PDCDA multilayers on flat surfaces and in nanoporous template. PDCDA multilayers were characterized using optical (UV-vis, fluorescence, ellipsometry, FTIR) spectroscopies, ionic current-voltage ( I- V) analysis, and scanning electron microscopy. Ellipsometry, FTIR, electronic absorption and emission spectroscopies showed a uniform DCDA deposition at each deposition cycle. Our optical spectroscopic analysis indicates that carboxylate-zirconium interlinking chemistry is robust. To explain the disorganization in the alkyl portion of PDCDA multilayer films, we propose carboxylate-zirconium interlinkages act as "locks" in between PDCDA layers which restrict the movement of alkyl portion in the films. Because of this locking, the induced-stresses in the polymer chains can not be efficiently relieved. Our ionic resistance data from I- V analysis correlate well with calculated resistance at smaller number of PDCDA layers but significantly deviated for thicker PDCDA nanotubes. These differences were attributed to ion-blocking because some of the PDCDA nanotubes were totally closed and the nonohmic and permselective ionic behaviors when the diameter of the pores approaches the double-layer thickness of the solution inside of the nanotubes.     

溶液电沉积法制备苝酰亚胺类化合物薄膜

溶液电沉积法是一种具有沉积时间短,可以常温沉积以及沉积物在基底上附着力高等优点的薄膜制备方法.本文用水合肼增溶苝酰亚胺类化合物(PTCDI)的方法制备了可用于溶液电沉积的苝酰亚胺类化合物溶液.用紫外-可见分光光度法(UV-Vis)对溶解的过程进行了表征,并用顺磁共振(ESR)验证了水合肼对PTCDI的增溶过程实质上是化学反应过程.在制备苝酰亚胺类化合物溶液的基础上,采用阳极电沉积法在ITO导电玻璃上沉积出了薄膜.采用UV-Vis,扫描电镜(SEM)和X射线衍射仪(XRD)对薄膜进行了表征,证实得到了表面较为平整、具有可控结晶结构和形貌的PTCDI薄膜以及具有较宽光谱吸收范围的复合薄膜.     

Effects of UV irradiation on tribological properties of nano‐TiO2 thin films

One‐layer and two‐layer nano‐TiO₂ thin films were prepared on the surface of common glass by sol–gel processing. Water contact angle, surface morphology, tribological properties of the films before and after ultraviolet (UV) irradiation were investigated using DSA100 drop shape analyzer, scanning probe microscopy (SPM), SEM and universal micro‐materials tester (second generation) (UMT‐2MT) friction and wear tester, respectively. The stored films markedly resumed their hydrophilicity after UV irradiation. But UV irradiation worsened tribological properties of the films. After the film was irradiated by UV, the friction coefficient between the film and GCr15 steel ball increased about 10–50% and its wear life shortened about 20–90%. Abrasive wear, brittle break and adherence wear are the failure mechanisms of nano‐TiO₂ thin films. It was believed that UV irradiation increased surface energy of the film and then aggravated adherence wear of the film at initial stage of friction process leading to severe brittle fracture and abrasive wear. Copyright © 2009 John Wiley & Sons, Ltd.     

TiO2 films loaded with silver nanoparticles: control of multicolor photochromic behavior

Ag-TiO(2) films exhibiting multicolor photochromism were prepared by photoelectrochemical reduction of Ag(+) to Ag nanoparticles in nanoporous TiO(2) films under UV light. Color of the Ag-TiO(2) film, initially brownish-gray, changes under a colored visible light to the color of the light and reverts to brownish-gray under UV light. Their chromogenic properties were improved by simultaneous irradiation for Ag deposition with UV and blue lights to suppress the formation of anisotropic Ag particles. Nonvolatilization of a color image was also achieved by removing Ag(+) that was generated during the irradiation with a colored light. Once nonvolatilized, the image can be reproduced by UV light, even after the image is discolored under white light. This new effect evidenced that nanopores in the TiO(2) film determine the resonance wavelengths of the Ag particles, as their molds. In addition, solvatochromic behavior of the Ag-TiO(2) film proved that nanospaces left around the Ag nanoparticles affect the resonance wavelengths of the Ag particles.     

Modification and Characterization of Chitosan Films Using 3-trimethoxyl Silyl Propylmethacrylate

The biodegradable flexible chitosan film was prepared by solution casting. The physico-mechanical properties, polymer loading (PL), gel content and water uptake of the chitosan film were studied. The tensile strength (TS) and % elongation at break (Eb) of the uncured chitosan film were 7.0 (MPa) and 8%, respectively. Four formulations were developed using 3-trimethoxyl silyl propylmethacrylate (TSPMA) (varied from 10–80% by weight) in methanol along with photoinitator (Darocur-1664). The raw chitosan films were then soaked in the prepared formulations and cured under UV radiation at different intensities to improve the physico-mechanical properties of the films. TS for the photocured chitosan film was 28.0 (MPa) which was 4 times higher compared to the uncured chitosan film. This TS was obtained for the formulation containing 30% silane (TSPMA) at 24th UV pass for 4 min soaking time. The maximum PL of 45.1% was obtained for the same formulation at 24th UV pass for 4 min soaking time. The water uptake and gel content of the photocured chitosan films were also studied. The scanning electron micrographs of the photocured chitosan film showed smooth surface, compact and homogeneous structure.     

Aqueous sols of oligo(ethylene glycol) surface decorated polydiacetylene vesicles for colorimetric detection of Pb 2+

A series of ethylene glycol (EG), triethylene glycol (3EG) and pentaethylene glycol (5EG) esters of 10,12-pentacosadiynoic acid (PCDA) are synthesized. The glycol ester lipids can be hydrated and well dispersed in water but they cannot form polydiacetylenes upon UV irradiation. They however can be mixed with PCDA up to 30 mol% and polymerized to form blue sols. The mixed polydiacetylene sols show blue to red thermochromic transition with two-stepped transition temperatures. The first transition temperature decreases with the increase of the glycol ester content as well as the length of their chains indicating greater fluidity of the self-assembled structure due to less collaborative hydrogen bonding among the lipid head groups. These mixed polydiacetylene sol prepared from 30 mol% of the penta(ethylene glycol) ester show linear colorimetric response selectively to Pb²⁺ in the range of 5-30 μM.     

大功率激光制备a-C和a-C∶H类金刚石膜的光学性能研究

采用大功率高重复频率准分子激光溅射热解石墨靶制备了类金刚石碳膜, 研究了实验条件对类金刚石膜光学性能的影响, 发现氢可以提高膜中sp3键的含量和膜的光学透过率. 在实验参数范围内, 膜的光学性能随着氢压的增加而提高. 根据类金刚石膜的反应沉积机理对上述结果进行了分析、解释.     

Photovoltaic Behaviour of Titanyl Phthalocyanine Thin Films and Titania Bilayer Films

Summary: Titanyl phthalocyanine (TiOPc) thin films were prepared using evaporation and surface polymerization by ion-assisted deposition (SPIAD) in a vacuum deposition system. These films were characterized by means of ultraviolet and X-ray photoelectron spectroscopy as well as UV/Vis absorption spectroscopy. Valence band and elemental content indicated that phthalocyanine electronic and chemical structures were largely preserved during SPIAD. Further, bilayer thin films of titania (TiO₂) and SPIAD TiOPc were prepared. TiO₂ film was deposited by reactive magnetron sputtering of TiO₂ target. Study of the structured samples was focused on the optical and electrical properties of the composite films. The films were characterized by non-contact photovoltage measurements and UV-Vis spectroscopy. These results suggest there is a possibility to use these bilayer thin films in photovoltaic solar cells, however further experiments to improve conductivity of the films will be required.     

Characterization of vapor deposition polymerized polyimide thin films

Vapor deposition polymerized (VDP) polyimide (PI) thin films were prepared and characterized by using thermogravimetrical analysis (TGA), scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared (FTIR), and bending-beam techniques. The film properties investigated were thermal stability, wet-etching characteristics, surface topology, imidization characteristics, internal stress upon curing and thermal cycling, and hygroscopic stress upon moisture diffusion. Markedly different characteristics are observed for the VDP-PI films when comparing with the conventional ones. They seem denser in film structure and have better mechanical properties, but are somewhat less stable in thermal resistance. © 1996 John Wiley & Sons, Inc.