An investigation on a novel PDLC film's fabrication and its electro-optical properties

A polymer dispersed liquid crystal (PDLC) film that has good electro-optical properties is produced by the method of polymerized-induced phase separation. Based on the application foreground, its capability parameters, such as contrast ratio, work voltage, and visual angle, are characterized for the first time by a white light but not a fixed wavelength light. The results show the PDLC film has a low work-voltage of 20 V, more than 150° visual angle, high stability, and long lifetime. The differences between plastic and glass ITO-coated substrates of PDLC films are also studied in this paper. The plastic substrate has better property and will have a wider perspective especially in the portable, tender and folded display devices. Due to adjustable properties of film by electric field, PDLC has the potential application for display device, sensor, switch, grating, and new generation analytical apparatus.     

Facile and robust strategy to antireflective photo-curing coating through self-wrinkling

We reported a facile and bio-inspired strategy for obtaining antireflective(AR) coating through polymerization-induced self-wrinkling. Upon irradiation of light, the complex wrinkle micro-patterns with different morphologies were generated spontaneously on the surface of coating during photo-crosslinking, which enables the photo-curing coating can decrease reflection. The resulting photo-curing coating exhibits a high transmittance over 90% and low reflection below 5%～8%, with an efficiency antireflection of 4%～7% compared to the flat blank coating. The successful application of these AR coatings with wrinkles pattern to encapsulate the thin film solar cells results in appreciable photovoltaic performance improvement of more than 4%～8%, which benefits from the decrease of the light reflection and increase of optical paths in the photoactive layer by the introduction of wrinkling pattern.Furthermore, the efficiency improvements of the solar cells are more obvious, with a remarkable increase of 8.5%, at oblique light incident angle than that with vertical light incident angle     

Plastic supported platinum modified nickel electrode and its high electrocatalytic activity for sodium borohydride electrooxidation

A novel plastic/multi-walled carbon nanotube(MWNTs)-nickel(Ni)-platinum(Pt) electrode(PMNP) is prepared by chemical-reducing Pt onto the surface of Ni film covered plastic/MWNTs(PM) substrate. The MWNTs are adhered by a piece of commercial double faced adhesive tape on the surface of plastic paper and the Ni film is prepared by a simple electrodeposition method. The morphology and phase structure of the PMNP electrode are characterized by scanning electron microscopy,transmission electron microscope and X-ray diffractometer. The catalytic activity of the PMNP electrode for Na BH4 electrooxidation is investigated by means of cyclic voltammetry and chronoamperometry. The catalyst combines tightly with the plastic paper and exhibits a good stability. MWNTs serve as both conductive material and hydrogen storage material and the Ni film and Pt are employed as electrochemical catalysts. The PMNP electrode exhibits a high electrocatalytic performance and the oxidation current density reaches to 10.76 A/(mg·cm) in 0.1 mol/dm3 Na BH4at0 V,which is much higher than those in the previous reports. The using of waste plastic reduces the discarding of white pollution and consumption of metal resources.     

STUDY ON PHOTO-INDUCED ORIENTATION OF A NOVEL PHOTO-ALIGNMENT FILM WITH SURFACE ENHANCED RAMAN SCATTERING （SERS） SPECTROSCOPY

Surface enhanced Raman scattering (SERS) spectroscopy was first utilized to study the photo-orientation behaviour of the photoreactive groups on a novel photo-alignment film surface and elucidate the generation mechanism of pretilt angle. The novel photo-alignment film was prepared by spin-coating a solution of ladderlike polysiloxane (LPS) bearing dual photoreactive group on an ITO surface and by irradiation with linear-polarized ultraviolet (LPUV) light. A Si-H terminal compound (M) containing an identical photosensitive part has been used to fabricate a model film for SERS investigation.     

Efficiency improvement of flexible dye-sensitized solar cells by introducing mesoporous TiO2 microsphere

Mesoporous TiO2microsphere(MTM)was synthesized via a simple solution route and then mixed with commercial TiO2(P25)to form highly homogeneous and stable TiO2colloid by simple hydrothermal treatment.The TiO2colloid was coated onto the plastic conductive substrate to prepare mesoporous TiO2film for flexible dye-sensitized solar cells(DSSCs)by low-temperature heat treatment.The influence of MTM content on the physicochemical properties of the flexible TiO2film was characterized by scanning electron microscope,transmission electron microscopy,X-ray diffraction,energy-dispersive X-ray spectrometer,N2adsorption-desorption isotherms,UV–vis absorption and diffuse reflectance spectra.It is revealed that with increasing the MTM content,the dye-loading capability of TiO2film and light-harvesting efficiency of flexible DSSCs are improved due to MTM having high surface area and acting as a light scattering center,respectively,resulting in the enhancement of photocurrent of flexible DSSCs.However,more and larger cracks having negative effect on the performances of flexible DSSCs are formed simultaneously.Under the optimal condition with MTM content of 20%,a flexible DSSC with overall light-to-electric energy conversion efficiency of 2.74%is achieved under a simulated solar light irradiation of 100 mW cm 2(AM 1.5),with 26%improvement in comparison with DSSCs based on P25 alone.     

电沉积法制备金属纳米线阵列膜的偏光特性

Metal nanowire array films were prepared by electrodepositing Cu, Ag, Ni, Co and Cu-Ag on porous anodic alumina film. Optical transmittance of both the porous anodic alumina film and metal nanowire array film was measured in the wavelength range of 400---2600 nm under an obliquely incident light. The experimental results show that metal nanowire array films exhibit a prominent polarization function. It was found that optical polarization properties can be improved by choosing suitable kinds of electrodepositing metal, controlling the shape and length of nanowire, and changing the incident angle.     

PLASMA POLYMERIZATION OF ACETYLENE/CO_2/H_2

A study has been made on the plasma polymerization of acetylene/CO_2/H_2 in a capacitively coupled RF plasma. The monomer mixture yielded a crosslinked film with light brown color. A kinetic study is reported for the plasma polymer ization of acetylene/CO_2/H_2. The effects of discharge power level and reactor geometry on the rate of polymer formation are reported. The structure of the plasma polymer is investigated by IR study.     

IDENTIFICATION OF DYNAMIC BEHAVIOUR OF LIGHT-POTENTIAL TRANSDUCTION SYSTEM IN PHOTORECEPTOR OF CALLIPHORA ERYTHROCEPHALA USING IRS-STIMULI

The linear dynamic behaviour of the light-potential transduction system in photorceeptor of Calliphora erythrocephala has been studied through the cross-correlation method using InverseRepeat Sequences and the lineal model of phototransduction is provided. The impulse response function and frequency characteristics have been determiued in the condition of background illumination.The results suggest that the R1-6 is equipped with a gain and time constant control mechanism which depends upon the adaptation level of the system under study.It becomes evident that the IRS correlation method is powerful to quantify the dynamic characteristics of the system containing nonlinearities and will become a very popular application for the study of biological sensory systems.The visual receptor cells R1-6 in the fly are the most sensible choice for the study of the light-potential transdnction system of the eye. The input of the system is the temporarily varying light intensity applied upon the eyes of the fly and th     

CO HYDROGENATION OVER HIGHLY DISPERSED Fe/AlPO_4-5 CATALYST

The Fe/AlPO_4-5 catalyst is prepared by a new method,SMAI,andcharacterized by XPS,ESR and magnetic measurement techniques.The sur-face active phase iron exists as Fe~0 and its average diameter is below 4.0 nm.The catalyst has high activity and selectivity for light hydrocarbons in CO hy-drogenation.Moreover,the catalyst has a higher stubility.TPSH,Mossbauerand XPS are used to characterize the used catalyst.The results show that thesurface phases of used catalyst are mainly iron carbides,and only a smallamount of graphitic surface deposit is detected.The main reason of the deacti-vation is the accumulation of iron particles,not the deposit of the graphite.Thecatalytic properties of SMAI catalysts are attributed to the special prepartionmethod and unique crystal structure and chemical composition of AIPO_4-5molecular sieves.     

Analysis of Phthalate Esters in Air,Soil and Plants in Plastic Film Greenhouse

The phthalate esters such as MDP,DEP,BDP and DEHP in air,soil and plant smples in plastic film greenhouse were clean up with fine silica gel column and determined with HPLC.It was found that the concentrations of PEs in ari and soil samples in plastic film greenhouse are much higher than those of contrast samples. But concentration of PEs in plants in plastic film greenhouse are not remarkably affected by the pollution of air and soil.     

Cesium lead halide perovskite nanocrystals for ultraviolet and blue light blocking

Using cesium lead halide perovskite nanocrystals, CsPb(Cl/Br)_3, as a light absorber, we report a highly effective UV and blue light blocking film. The CsPb(Cl/Br)_3 nanocrystals are well dispersed in the ethyl cellulose(EC) matrix to compose a UV and blue light shielding film, and the absorption edge of the film is tunable by adjusting Cl to Br ratio using anion exchange. The CsPbCl_2 Br-EC film exhibits a transmittance of 5% at 459 nm, 90% at 478 nm and 95% in the range of 500–800 nm, which makes it excellent for UV and blue light shielding. In addition, the as-prepared EC-CsPb(Cl/Br)_3 film shows excellent photostability under UV irradiation. Results demonstrate that this EC-CsPb(Cl/Br)_3 based materials with sharp absorbance edges, tunable blocking wavelength, and high photostability can be useful for the applications in UV and blue light blocking and optical filters     

Phase separation in mixtures of thermotropic liquid crystals and flexible polymers

The spinodal equation and the concentration-induced anisotropic-isotropic transition equation of the mixtures of thermotropic liquid crystals and flexible polymers have been studied by using the molecular field theory The calculations of the phase diagrams of this system show that,besides the isotropic classic spinodal curve,there ex ists an anisotropic spinodal curve which has not been reported in literature.These two spinodal curves can be linked up by the concentration-induced anisotropic-isotropic transition line.In the various phase regions,demixing may take place due to different phase separation mechanisms.The phase equilibrium curve cannot always join the.spinodal curve at a critical point.These results are considered very meaningful for the understanding of the special properties of liquid crystal/polymer composites and very useful for controlling the morphology and the performance of PDLC materials     

LAMINATION OF POLYMER FILMS BY BULK SURFACE PHOTOGRAFTING PROCESS AND PROPERTIES

A new process for lamination of polymer films by "bulk surface photografting" has been developed. The chemicalcomponent of the invention is that the curing of reactive solution between two substrates is initiated by the surface freeradicals produced by aromatic ketones and surface-hydrogen of substrates. Using the new approach, two or more polymerfilms are bonded together by a grafted polymer network which is grafted to adjacent substrate surfaces. The technique hasbeen applied to film substrates of different polymers such as polyolefins, polyesters. and polyamides which have abstractablehydrogens at the surface. The photolaminated film composites containing carrier films and an intermediate functional film of low permeability give strong laminates with high barrier properties, e.g. for oxygen and air.     

Multiscale and multicomponent layer by layer assembly of optical thin films triggered by electrochemical coupling reactions of N-alkylcarbazoles

The integration of multiscale and multicomponent of molecules and nanoparticles into thin films for applications requires the abilities of controlled their processing and assembly,which has been an great challenge because of the difficulty in manipulating the various materials such as small molecules,complexes,polymers,and inorganic nanomaterials through synergetic combinations of chemical or physical fabrications.Eletropolymerization is of great significance to fabricate polymeric film materials straight on the conductive substrates with tunable morphologies and thicknesses.However,unlimited electrochemical reactions(polymerization)have been usually leading to disadvantageous in ill-defined structure and highly doped state.Thanks to finding of exceptional electrochemical reaction(oligomerization)of N-alkylcarbazole,electrochemical layer by layer assembly has emerged as a promising strategy for a wide library of applications.The capability of this strategy can manipulate various molecules and nanoparticles into the scale and component controllable thin films.Unlike other electropolymerizable precursors such as aniline and thiophene,the resulting di-N-alkylcarbazole is transparent in the visible light region and thus does not impair the intrinsic properties of the components in the film.This account highlights of the typical findings in investigating both single-and multi-components thin films as a forum for discussing new opportunities in exploiting novel designs and applications of optical thin films.     

Organic permeable base light-emitting transistor: a new concept device architecture for display technology

正As an important part of the information industry,display technology has been playing a very important role in the development of information technology.Due to the obvious advantages in thickness,color gamut,view angle and contrast ratio,organic light-emitting diodes (OLEDs) are recognized as one of the most important display technologies and have been successfully commercialized in mobile phones and TVs.However,the detrimental complex device fabrication processes and high operation voltage required by drive transistor backplanes for OLED active-matrix displayssignificantly prevent their wider applications.     

Two Photoelectrochemical Processes for TiO2 Electrode under UV Illumination

TiO2 thin film electrode was prepared by a sol-gel method on ITO substrates. Cyclic voltammetric behavior of the ITO/TiO2 electrode under ultraviolet (UV) illumination was investigated in the solution of Na2SO4.There are two photoelectrochemical processes for TiO2 electrode under UV illumination.One is a fast process,which results in the appearance of anodic photocurrent.The anodic photocurrent will appear and disappear with the light on and off.The other is a slow process,which will be responsible for the appearance of an oxidative peak. When the electrode is illuminated under UV light for a long time,a new oxidative peak can be observed.The peak current increases with the increase of UV illumination time.It is assumed that the new peak belongs to the oxidation of Ti^3 ,which formed and accumulated on the electrode surface during the UV illumination.A detailed mechanism is proposed on the base of these two photoelectrochemical processes.It is assumed that the change of hydrophilicity of TiO2 thin film may be related to the slow process while the film irradiated by UV light.     

Synergistic effect of TiO_2 hierarchical submicrospheres for high performance dye-sensitized solar cells

The performance of dye-sensitized solar cells(DSCs) could be improved by using rationally designed mesoporous film structure for electron collection, dye adsorption and light scattering. The development of a novel double layer film prepared by TiO_2 hierarchical submicrospheres and nanoparticles was reported in this article. The submicrospheres were composed of rutile nanorods of 10 nm diameter and the length of 150–250 nm, which facilitated fast electron transport, charge collection and light scattering. Using a double layer structure consisting of the 10 wt% film as a dye loading layer and the 50 wt% film as the light scattering layer, C101 sensitizer and liquid electrolyte, DSC yielded power conversion efficiency of 9.68% under 1 sun illumination.     

NIR photosensitizers activated by γ-glutamyl transpeptidase for precise tumor fluorescence imaging and photodynamic therapy

Photodynamic therapy(PDT), a light triggered therapeutic mode, has been recognized as an attractive treatment for oncotherapy.The phototoxicity to normal tissues during treatment limited the development of PDT owing to the always "on" properties of photosensitizers. Activatable photosensitizers are of great importance for improving the selectivity of PDT. Herein, we regarded the overexpressed GGT(γ-Glutamyl transpeptidase) enzyme in tumor cells as a biomarker and developed an activatable photosensitizer Cy-GGT by decorating a specific recognition moiety of GGT, L-glutamic acid, to a hemicyanine dye based on photosensitizer Cy-NH_2. Cy-GGT was in the "off" state with negligible fluorescence and suppressed singlet oxygen generation,but it could be specifically hydrolyzed to Cy-NH_2 in the presence of GGT, accompanied with significant fluorescence recovery and singlet oxygen generation increase under light irradiation. The in vitro and in vivo studies indicated that Cy-GGT was suitable for precise tumor imaging and could work as an efficient photosensitizer for inhibiting tumor growth.     

ELECTRICALLY CONDUCTIVE COMPOSITE PREPARED BY ELECTROCHEMICAL POLYMERIZATION OF PYRROLE IN POLY-(p- PHENYLENE TEREPHTHALAMIDE) MATRIX

The preparation of PPy/PPTA conductive composite films by electrochemical method is presented.The first step is to cast a thin layer of poly (p-phenylene-terephthalamide) (PPTA) on a slice of Pt working electrode. The second step is to electrochemically polymerize pyrrole on the PPTA/Pt working electrode. Both of the electrical conductivity and the mechanical properties of the PPy/PPTA composite film are better than those of the pure PPy film, and the film has excellent flexibility at low temperature, even in liquid nitrogen.The SEM picture of the cross-section of PPy,/PPTA composite film showed that the two components were well mixed.Cyclic voltammograms of PPy,/PPTA film in aqueous solution showed that the conductive films could be reduced and reoxidized.     

Poly(ethylene terephthalate)/carbon black composite fibers prepared by electrospinning

Poly(ethylene terephthalate)(PET)/carbon black(CB) composite fibers with improved mechanical properties in tensile modulus and tensile strength are prepared by eletrospinning. Stable dispersions suitable for electrospinning are obtained by dispersing melt pre-compounded PET/CB composites in hexafluoroisopropanol. The fiber morphology and CB dispersion are investigated by FESEM and TEM. The addition of CB has no obvious effect on fiber diameter, and the average fiber diameters for all the samples are around 2-3 μm. CB in the fibers is in the form of submicron-sized clusters. The thermal properties of the PET/CB composite fibers are evaluated by DSC, showing almost unchanged melting temperature and crystallinity. Uniaxial tensile tests are used to measure the mechanical properties of the PET/CB composite fiber mats. The fiber mats containing 1 wt%-8.5 wt% CB have significantly improved tensile modulus compared to neat PET fiber mat, showing reinforcing effect of CB. The electrical conductivity of the fiber mats has also been tested.