Search results for "FILMS"
showing 10 items of 2839 documents
Electrical Voltage Control of the Pressure-Induced Spin Transition at Room Temperature in the Microporous 3D Polymer [Fe(pz)Pt(CN)4]
2019
Fine control and direct monitoring of the spin crossover properties driven by pressure at room temperature are reported for the porous three-dimensional coordination polymer {Fe(pz)[Pt(CN)4]} by us...
Perovskite solar cells prepared by flash evaporation
2015
A simple vacuum deposition method for the preparation of high quality hybrid organic-inorganic methylammonium lead iodide perovskite thin films is reported. When sandwiched in between organic charge transporting layers, such films lead to solar cells with a power conversion efficiency of 12.2%.
Solvent Determines Nature of Effective Interactions between Nanoparticles in Polymer Brushes
2015
We study the effective interaction between two parallel rod-like nanoparticles in swollen and collapsed polymer brushes as a function of penetration depth by 2D self-consistent field calculations. In vertical direction, the interaction is always attractive. In lateral direction, the behavior under good and poor solvent conditions is qualitatively different. In swollen brushes (good solvent), nanoparticles always repel each other. In collapsed brushes (poor solvent), we identify two different regimes: an immersed regime, where the nanoparticles are fully surrounded by the brush, and an interfacial regime, where they are located in the interface between brush and solvent. In the immersed regi…
Processability and Properties of Re-Graded, Photo-Oxidized Post-Consumer Greenhouse Films
2005
The recycling of post‐consumer plastics leads, in general, to secondary materials having properties worse than those of the reclaimed material and certainly worse than those of the same virgin polymer. This is because of the degradation undergone by the objects during their use and because of the thermo‐mechanical degradation undergone during the reprocessing operations. The change of the molecular architecture is responsible for this worsening of properties. The use of stabilizing systems can slow the degradation during the melt processing but cannot give any improvement of the final properties of the material. In order to enhance the properties of the recycled plastics, some rebuilding of…
Single-Molecule Spectroscopy of MEH-PPV Polymer Molecules in Different Host Matrices
2009
Fluorescence emission and excitation spectra of single MEH-PPV molecules dispersed in three different host polymers (PMMA, PS, and Zeonex) have been recorded at 1.2 K. We observed only minor effects of the host matrix on the following parameters: the ratios of single-chromophoric to multichromophoric emission, the widths of the distributions of emission maxima, and the (generally very low) fraction of emission spectra with sharp zero-phonon lines. The differences are tentatively attributed to different conformations of MEH-PPV chains, subtle variations in local chromophore−matrix interactions, and/or different distributions of conjugation lengths of emitting chromophores, respectively. Usin…
Ion bombardment of polyethylene—influence of polymer structure
2007
Abstract Polyethylenes of various macromolecular and supermolecular structures were studied from the point of view of their susceptibility to an ion beam treatment. An influence of molecular weight (Mw), molecular weight distribution (Mw/Mn) and the degree of branching were compared within the set of low-density polyethylenes (LDPE) studied. An influence of the length of branches was compared between LDPE, linear low-density (LLDPE) and high-density (HDPE) polyethylenes. An influence of the degree of crystallinity and the morphology of a crystalline phase were compared for HDPE samples solidified under various thermal conditions and ultra-high molecular weight polyethylene (UHMWPE). Plate p…
Covalently attached polymer mono- and multilayers on silanized glass substrates
1996
Abstract Applying grazing incidence FTIR and ellipsometry, the reaction of poly [(1-methyl-vinyl isocyanate)-alt-(maleic anhydride)](IAP) with amino-silanized glass and silicon oxide surfaces has been investigated. A reactive surface containing isocyanate and anhydride groups was formed after the adsorption of the polymer. The layer could be further functionalized using 2-aminoethanol. Multilayers could be built up by adsorbing a second layer of IAP onto an already reacted first layer of IAP.
Formation of nanorods by self-assembly of alkyl-substituted polyphenylene dendrimers on graphite
2000
Alkyl-substituted polyphenylene dendrimers with a tetrahedral or disk-like shape form self-assembled monolayers on graphite (HOPG) which show complex supramolecular structures, such as parallel rods of 6 nm diameter or two-dimensional crystals.
Effect of the Components Molar Mass and of the Mixing Conditions on the Compatibilization of PE/LCP Blends by PE-g-LCP Copolymers
1999
The rheology, morphology, and mechanical properties of blends of high-density polyethylene (HDPE) with a semiflexible liquid crystalline copolyester (SBH) were studied in order to assess the compatibilizing ability of added PE-g-SBH copolymers, and its dependence on the molar mass of the PE matrix, and on the technique used for blend preparation. The PE-g-SBH copolymers were synthesized as described in previous articles, either by the polycondensation of the SBH monomers in the presence of a functionalized PE sample containing free carboxyl groups, or by reactive blending of the latter polymer with preformed SBH. Two samples of HDPE having different molar masses, and two samples of SBH with…
Polyisoprene-carbon black nanocomposites as tensile strain and pressure sensor materials
2004
Abstract Electrically conductive polymer composites (ECPC) are shown as prospective large-size flexible pressure and stretch sensors for detecting of dangerous deformations and vibrations of vehicle parts. Reversible change of resistance dependent on stretch and pressure is obtained in electro-conductive polymer nanocomposites. At certain concentrations of carbon nano-particles a change of electrical resistance by more than four orders is observed at 40% relative stretch. The maximum sensitivity of nanocomposites is observed in the vicinity of the transition of electro-conductive percolation. Nanocomposites exhibit a very weak semiconductor-like temperature dependence of resistance. The ten…