Transmittance Of Composite Films Research Articles

Polyvinyl alcohol flame retardant film based on halloysite nanotubes, chitosan and phytic acid with strong mechanical and anti-ultraviolet properties

The research of additive biomass flame retardants is becoming more and more popular. In this work, amino modified halloysite nanotubes (A-HNTs), chitosan (CS) and phytic acid (PA) were introduced into polyvinyl alcohol (PVA) matrix to construct PA/A-HNT/CS/PVA organic-inorganic composite film with hydrogen bond and covalent bond cross-linking network structure. Adding PA/A-HNT/CS can remarkably improve the mechanical strength, UV resistance and thermal stability of PVA film. Compared with control PVA film, the transmittance of composite film in ultraviolet region decreases from 90 % to <15 %, and the tensile strength raises from 19.8 MPa to 31.0 MPa. The thermal decomposition temperature of the composite film increases, the weight loss rate decreases obviously, and the carbon residue can reach 26 wt% at 700 °C. The limiting oxygen index increases from 18.5 % to 32.2 %. Furthermore, the addition of this flame-retardant system can obviously reduce the combustion intensity of PVA, and its flame-retardant grade can reach V-0. It is of great significance to expand the application of PVA and the development of biomass flame retardant.

Preparation of treelike and rodlike carboxymethylated nanocellulose and their effect on carboxymethyl cellulose films

AbstractIn this work, carboxymethyl cellulose (CMC) with low substitution degree, followed by different posttreatments, was applied to prepare treelike CMC nanofibrils (CMCNFs) and rodlike CMC nanocrystals (CMCNCs), and their performance in CMC composite film was evaluated simultaneously. From transmission electron microscopy results, it was found that the treelike CMCNCFs exhibited a lager aspect ratio compared to the rodlike CMCNCs. As for reinforcing CMC film, 4 wt% was the best adding amount, at this time, the tensile strength of CMC/CMCNFs and CMC/CMCNCs composite films was increased by 72.1% and 47.3%, respectively. Moreover, adding these nanofillers to CMC also could enhance the thermal stability of composite films slightly, while the transmittance of composite films was reduced at the same time. In addition, CMC/CMCNFs film was designed as a packaging box to determine its performance. Therefore, this study could reveal the differences of properties for composites with different types of nanocellulose and provide a foundation for further application of nanocellulose.

Effect of Sputtering Parameters on the Property of TaN&lt;sub&gt;x&lt;/sub&gt;/Ag/TaN&lt;sub&gt;x&lt;/sub&gt; Low-Emissivity Film

The effect of deposition parameters such as sputtering power, nitrogen flow rate and thickness of TaNx on the optical performance and chemical durability of composite Tantalum nitride /Ag/ tantalum nitride (TaNx/Ag/TaNx) films was investigated. When the configuration of composite film was TaNx (60nm)/Ag (12nm)/TaNx (60nm) accompanying with the sputtering power 120W and the nitrogen flow rate 50sccm, the visible light transmittance of composite film could reach up to 80% at the wavelength of 550nm and the emissivity was 0.087. In addition, the chemical durability of the coatings was evaluated and the results indicated that the low-e coating presented very good chemical durability.

Influence of PEDOT:PSS film doped with sorbitol on performances of organic solar cells

In this article, the PEDOT:PSS doped with sorbitol film is fabricated on an ITO substrate by blending-spin coating method and used as a hole-extraction layer for organic solar cell (OSC). The effect of sorbitol concentration on the photovoltaic performance of the device is investigated based on P3HT:PCBM blend. Compared with a pristine device (i.e., without sorbitol), the sorbitol-doped (8wt %) OSC shows that the short-circuit current density, the fill factor and the power conversion efficiency are inereased from 8.82 to 9.03mA/cm2, 0.43 to 0.474 and 2.12% to 2.39 % (i.e., by about 13%), respectively. The canse of the improvement on performance of the device is discussed, showing that the increase in conductivity and transmittance of composite films is due to the improvement on OSC performances achieved through the incorporation of sorbitol into hole-extraction layer of PEDOT:PSS. The former leads to a lower series resistance of the device, while the latter gives rise to the improvement on the photo-induced carriers of the photovoltaics cells.

Optical properties of ferroelectric nanocrystal-containing polymer BaTiO3∕polycarbonate films

BaTiO 3 (BT)-nanocrystal-doped polycarbonate polymer composite thin films (BT/PC) with different BT concentrations were prepared by spin-coating method. Ultrafine BT (∼40–50nm) nanocrystals with pure perovskite tetragonal phase were synthesized by hydrothermal method. The structure of BT nanocrystals and composite films were studied by means of x-ray diffraction and transmission scanning microscopy. The composite films were poled with a high electric field at a suitable temperature to yield a noncentrosymmetric arrangement and produce better electro-optic properties. The poling condition under external electric field was optimized through the dielectric properties of BT and PC polymer and the effective-field intensity theory. The electro-optic (EO) coefficients and transmittance of composite films with various BT concentrations were also evaluated. The average effective linear EO coefficient and figure of merit of 20-wt % BT-doped composite films were about 63.1 and 103.1pm∕V, respectively. BT/PC composite films show excellent electro-optic properties for application in integrated optoelectronics and optics.

Reversible optical control of transmittance in polymer/liquid crystal composite films by photoinduced phase transition

We have demonstrated reversible change in transmittance of composite films, which are composed of an isotropic (I) polymer matrix and a host nematic (N) liquid crystal (LC) containing donor–acceptor type azobenzene LCs (AzoLCs) as photoresponsive molecules, by means of reversible phase transition in the LC domain. The composite films were prepared by in situ thermal polymerization-induced phase separation (PIPS) method from their homogeneous mixtures. Photoisomerization of AzoLCs was induced within the polymer network, and the resultant effect brought about isothermal change in transmittance. The photoinduced reversible and repeatable changes between opaque light scattering and clear transparent states were achieved effectively by irradiation with a monochromatic light at 366 nm. These changes are attributed to photochemical N–I phase transition and rapid thermal I–N phase transition in the host LC domain based on reversible change in molecular sharp of the guest AzoLCs. The optical effects were influenced by such factors as temperature of the composite films in the initial state and photoisomerization ability of the guest AzoLCs. The composite films acted as an optical switching material without polarizers.