Organic Sheets Research Articles

Fabrication of Patchable Organic Lasing Sheets via Soft Lithography

Here, we report a novel fabrication technique for patchable organic lasing sheet based on non-volatile liquid organic semiconductors and freestanding polymeric film with high flexibility and patchability. For this work, we have fabricated the second-order DFB grating structure, which leads to surface emission, embedded in the freestanding polymeric film. Using an ultra-violet (UV) curable polyurethaneacrylate (PUA) mixture, the periodic DFB grating structure can be easily prepared on the freestanding polymeric film via a simple UV curing process. Due to unsaturated acrylate remained in the PUA mixture after UV curing, the freestanding PUA film provides adhesive properties, which enable mounting of the patchable organic lasing sheet onto non-flat surfaces with conformal contact. To achieve laser actions in the freestanding resonator structure, a composite material of liquid 9-(2-ethylhexyl)carbazole (EHCz) and organic laser dyes was used as the laser medium. Since the degraded active materials can be easily refreshed by a simple injection of the liquid composite, such a non-volatile liquid organic semiconducting medium has degradation-free and recyclable characteristics in addition to other strong advantages including tunable optoelectronic responses, solvent-free processing, and ultimate mechanical flexibility and uniformity. Lasing properties of the patchable organic lasing sheet were also investigated after mounting onto non-flat surfaces, showing a mechanical tunability of laser emission under variable surface curvature. It is anticipated that these results will be applied to the development of various patchable optoelectronic applications for light-emitting displays, sensors and data communications.

Impact Behavior of Continuous Biaxial Reinforced Composites Based on Bio-Polyamides and Man-Made Cellulose Fibres

Abstract Composites based on thermoplastic matrix and glass or carbon fibre fabrics, like the so called organic sheets, show high potential for structural parts, e. g. in automotive applications. In this study renewable organic sheets based on bio-polyamides with a melting point above 200 °C and polypropylene for reference purposes were prepared. High energy absorption for these composites were expected regarding the high elongation at break (> 10 %) of the man-made cellulose fibres. In comparison to the cellulose reinforced composites, glass fibre composites were prepared. The complete or partly bio-based composites, with a thickness of approx. 2 mm, were manufactured by a high precision hot-press using the film-stacking-process considering less fibre degradation at high processing temperatures. Besides dart drop tests (penetration mode and impact mode) and optical microscopy were done to characterize the composites. The bio-based composites show lower density, higher energy absorption rates and lower damping values as a consequence of the cellulose fibres properties and the fibre-matrix-adhesion.

PfSMAD4 plays a role in biomineralization and can transduce bone morphogenetic protein-2 signals in the pearl oyster Pinctada fucata.

BackgroundMollusca is the second largest phylum in nature. The shell of molluscs is a remarkable example of a natural composite biomaterial. Biomineralization and how it affects mollusks is a popular research topic. The BMP-2 signaling pathway plays a canonical role in biomineralization. SMAD4 is an intracellular transmitter in the BMP signaling pathway in mammals, and some genomic data show SMAD4’s involvment in BMP signaling in invertbrates, but whether SMAD4 plays a conservative role in pearl oyster, Pinctada fucata, still need to be tested.ResultsIn this study, we identified a SMAD4 gene (hereafter designated PfSMAD4) in pearl oyster Pinctada fucata. Bioinformatics analysis of PfSMAD4 showed high identity with its orthologs. PfSMAD4 was located in the cytoplasm in immunofluorescence assays and analyses of PfSMAD4 mRNA in tissues and developmental stages showed high expression in ovaries and D-shaped larvae. An RNA interference experiment, performed by PfSMAD4 double-stranded RNA (dsRNA) injection, demonstrated inhibition not only of nacre growth but also organic sheet formation with a decrease in PfSMAD4 expression. A knockdown experiment using PfBMP2 dsRNA showed decreased PfBMP2 and PfSMAD4 mRNA and irregular crystallization of the nacreous layer using scanning electron microscopy. In co-transfection experiments, PfBMP2-transactivated reporter constructs contained PfSMAD4 promoter sequences.ConclusionsOur results suggest that PfSMAD4 plays a role in biomineralization and can transduce BMP signals in P. fucata. Our data provides important clues about the molecular mechanisms that regulate biomineralization in pearl oyster.

A shell regeneration assay to identify biomineralization candidate genes in mytilid mussels

Biomineralization processes in bivalve molluscs are still poorly understood. Here we provide an analysis of specifically expressed sequences from a mantle transcriptome of the blue mussel, Mytilus edulis. We then developed a novel, integrative shell injury assay to test, whether biomineralization candidate genes highly expressed in marginal and pallial mantle could be induced in central mantle tissue underlying the damaged shell areas. This experimental approach makes it possible to identify gene products that control the chemical micro-environment during calcification as well as organic matrix components. This is unlike existing methodological approaches that work retroactively to characterize calcification relevant molecules and are just able to examine organic matrix components that are present in completed shells. In our assay an orthogonal array of nine 1mm holes was drilled into the left valve, and mussels were suspended in net cages for 20, 29 and 36days to regenerate. Structural observations using stereo-microscopy, SEM and Raman spectroscopy revealed organic sheet synthesis (day 20) as the first step of shell-repair followed by the deposition of calcite crystals (days 20 and 29) and aragonite tablets (day 36). The regeneration period was characterized by time-dependent shifts in gene expression in left central mantle tissue underlying the injured shell, (i) increased expression of two tyrosinase isoforms (TYR3: 29-fold and TYR6: 5-fold) at day 20 with a decline thereafter, (ii) an increase in expression of a gene encoding a nacrein-like protein (max. 100-fold) on day 29. The expression of an acidic Asp-Ser-rich protein was enhanced during the entire regeneration process. This proof-of-principle study demonstrates that genes that are specifically expressed in pallial and marginal mantle tissue can be induced (4 out of 10 genes) in central mantle following experimental injury of the overlying shell. Our findings suggest that regeneration assays can be used systematically to better characterize gene products that are essential for distinct phases of the shell formation process, particularly those that are not incorporated into the organic shell matrix.

Effect of inhomogeneous temperature distribution on the impregnation process of the continuous compression molding technology

The demand for continuous fiber-reinforced thermoplastics has steadily increased during the last years due to their specific properties. But considering the applications in large-scale production, the price for the organic sheets is still too high in order to compete with the metal counterparts. A starting point for the reduction of the total costs is the acceleration of the impregnation process by in-plane polymer flow. For this reason, this scientific report provides an insight into the production process using a continuous compression molding machine. In order to analyze the in-plane polymer flow and its driving forces, a method for the evaluation of the pressure distribution is presented in a first step. The examination revealed a significant inhomogeneous pressure distribution for the whole pressing area, which could be affected by different temperature settings. Afterward, the impregnation quality was correlated with the different settings, followed by the illustration of a huge potential for increasing the impregnation speed.

A mild, efficient and catalyst-free thermoreversible ligation system based on dithiooxalates

We introduce dithiooxalates as efficient and catalyst-free thermoreversible hetero Diels–Alder linkers for applications in self-healing materials, organic sheets, mild ligation or complex architecture design.

Microstructure of iridescence-lacking pearl formed in Pinctada fucata

The iridescence-lacking pearl is regarded as a low-quality product because it shows no iridescent color which is generated by the interference of the light reflected at the organic–inorganic boundaries in the regulated interstratification of organic sheets and thin aragonite tablets. In this study, we investigated the microstructural difference between normal and iridescence-lacking pearls, as well as original nacreous layers in the shell of the pearl oyster, Pinctada fucata. Cross-sectional observation by scanning electron microscopy revealed abundant organic spherules of a few hundred nanometers in diameter attached to the inter-crystalline organic sheets in the iridescence-lacking pearl. The incoherent light scattered by the spherules inhibit the formation or emission of the iridescent color. The same spherules were also observed in hazy nacreous layers of the shell. The organic spherules often connected to the gap of inter-crystalline organic sheets implying that the spherules consist of same components of the organic sheets. Their abundance varies along the thickness of nacre, suggesting that their formation is determined by environmental factors, as well as genetic ones.

Nanoscale Transforming Mineral Phases in Fresh Nacre.

Nacre, or mother-of-pearl, the iridescent inner layer of many mollusk shells, is a biomineral lamellar composite of aragonite (CaCO3) and organic sheets. Biomineralization frequently occurs via transient amorphous precursor phases, crystallizing into the final stable biomineral. In nacre, despite extensive attempts, amorphous calcium carbonate (ACC) precursors have remained elusive. They were inferred from non-nacre-forming larval shells, or from a residue of amorphous material surrounding mature gastropod nacre tablets, and have only once been observed in bivalve nacre. Here we present the first direct observation of ACC precursors to nacre formation, obtained from the growth front of nacre in gastropod shells from red abalone (Haliotis rufescens), using synchrotron spectromicroscopy. Surprisingly, the abalone nacre data show the same ACC phases that are precursors to calcite (CaCO3) formation in sea urchin spicules, and not proto-aragonite or poorly crystalline aragonite (pAra), as expected for aragonitic nacre. In contrast, we find pAra in coral.

Dual Roles of the Lysine-Rich Matrix Protein (KRMP)-3 in Shell Formation of Pearl Oyster, Pinctada fucata

Matrix proteins play important roles in shell formation. Our group firstly isolated three cDNAs encoding lysine-rich matrix protein from Pinctada fucata in 2006. However, the functions of KRMPs are not fully understood. In addition, KRMPs contain two functional domains, the basic domain and the Gly/Tyr domain respectively. Based on the modular organization, the roles of their two domains were poorly characterized. Furthermore, KRMPs were then reported in other two species, P. maxima and P. margaritifera, which indicated that KRMPs might be very important for shell formation. In this study, the characterization and function of KRMP-3 and its two functional domains were studied in vitro through purification of recombinant glutathione S-transferase tagged KRMP-3 and two KRMP-3 deletion mutants. Western blot and immunofluorescence revealed that native KRMP-3 existed in the EDTA-insoluble matrix of the prismatic layer and was located in the organic sheet and the prismatic sheath. Recombinant KRMP-3 (rKRMP-3) bound tightly to chitin and this binding capacity was duo to the Gly/Tyr-rich region. rKRMP-3 inhibited the precipitation of CaCO3, affected the crystal morphology of calcite and inhibited the growth of aragonite in vitro, which was almost entirely attributed to the lysine-rich region. The results present direct evidence of the roles of KRMP-3 in shell biomineralization. The functional rBR region was found to participate in the growth control of crystals and the rGYR region was responsible to bind to chitin.

FOSSILS OF PUTATIVE MARINE ALGAE FROM THE CRYOGENIAN GLACIAL INTERLUDE OF MONGOLIA

Neoproterozoic carbonate successions provide a new taphonomic window into the diversification of eukaryotes. We report recently discovered macroscopic organic warty sheets (MOWS) in macerates of limestone from the ca. 662–635 Ma Taishir Formation (Tsagaan Olom Group, Mongolia). Sheets are applanate. One surface contains raised ridges and conspicuous, ∼ 100-µm-tall warty protuberances with depressed tops that enclose internal cavities containing cellular structures. The Taishir MOWS may be the remains of unusual bacterial, protistan, or fungal biofilms, or a previously undocumented, extinct taxon. However, multiple lines of evidence including the morphology of warty protuberances and the presence of cellular architecture within protuberances support the interpretation of MOWS as marine algae, perhaps a member of the Rhodophyta. Regardless of their specific taxonomic affiliation, MOWS increase the diversity of biota reported from the Cryogenian glacial interlude and indicate the presence of macroscopic and morphologically complex multicellular organisms in the Cryogenian.

Influence of Fabric Parameters on Surface Waviness of FRPC: An Experimental Investigation and Development of a Model on Surface Waviness

This paper deals with the surface development of continuous fiber-reinforced thermoplastic composites, so called organic sheets, during processing. To investigate the effect of the textile parameters on the surface development organic sheets with different steel wire fabrics and a polycarbonate matrix were manufactured using a laboratory press. The fabrics differed in fiber diameter and mesh size. The results showed that both textile parameters have a significant influence on the characteristic surface waviness of the FRPC. Increasing fiber diameters and mesh sizes lead to higher maximum waviness. Organic sheets with a fiber diameter of the reinforcement less or equal 50 μm could not be differentiated anymore and had no visible waviness. Based on the equation for linear thermal expansion a thermo rheological process model was developed to predict the surface waviness. The model describes the waviness creation including a pressure induced compensating polymer flow. A waviness comparison of experimental data with calculated results shows a good agreement.

A novel silver(i)-Keggin-polyoxometalate inorganic–organic hybrid: a Lewis acid catalyst for cyanosilylation reaction

A novel polyoxometalate (POM) hybrid material based on a Keggin polyanion and silver(I)–organic sheet, namely, [Ag4(apym)4(SiW12O40)]n (1), where apym = 2-aminopyrimidine, has been synthesized under hydrothermal conditions and characterized by elemental analysis, IR spectroscopy, thermal gravimetric analysis, powder X-ray diffraction and single-crystal X-ray diffraction. In the structure of 1, polyanions link 2D 3-connected 4·82-fes AgI–organic sheets to generate a 3D complicated framework. Moreover, the catalytic performance of 1 towards the cyanosilylation of carbonyl compounds has been tested under mild conditions, showing a high turnover number and turnover frequency.

A dynamic metal–organic supramolecular host based on weak π-stacking interactions incorporating 2D water-chloride-methanolic supramolecular sheet

Herein, we report the formation of a unique water-chloride-methanol 2D supramolecular network within the hydrophobic interlayer cavities of a novel flexible metal–organic supramolecular host (MOSH) framework formed by π-induced self-assembly of the monomeric metal–organic complex [Pr(1,10-phen)2(H2O)5]Cl3(H2O)(CH3OH) (1,10-phen=1,10-phenanthroline) (complex 1). Single crystal X-ray diffraction (SC-XRD), powder X-ray diffraction (PXRD) and spectroscopic techniques are used to characterize the complex. The structural analysis reveals that in this MOSH the discrete metal–organic moieties are connected by π⋯π interactions to form 2D metal–organic supramolecular sheet structures. The guest water and methanol molecules together with counter chloride anions stabilize in the MOSH framework through hydrogen bonding interactions between the 2D metal–organic supramolecular layers. The hydrogen bonding interactions among the coordinated water and guest species form a unique 2D supramolecular water-chloride-methanol sheet structure. Upon removal of guest water and methanol molecules by heat treatment the supramolecular framework gets shrunk but retains the crystallinity while upon re-absorption of water molecules it undergoes structural change with expansion of effective guest accessible void space. The flexibility of the supramolecular framework and the mechanism of thermally induced phase transformation in the MOSH are examined by PXRD study. The photoluminescence property of the complex 1 and the crystalline complex obtained after rehydration has been thoroughly investigated. The theoretical analysis has been performed to resolve the issue of stability of the 2D supramolecular water-chloride-methanol sheet in the MOSH framework and it has been found that for complex 1 the stabilization energy of the [(H2O)6-(CH3OH)-Cl3]n3− is 1949.427Kcal mol−1.

Synthesis of Two-Dimensional Analogues of Copolymers by Site-to-Site Transmetalation of Organometallic Monolayer Sheets

Monolayer sheets have gained attention due to the unique properties derived from their two-dimensional structure. One of the key challenges in sheet modification/synthesis is to exchange integral parts while keeping them intact. We describe site-to-site transmetalation of Zn(2+) in the netpoints of cm(2)-sized, metal-organic sheets by Fe(2+), Co(2+), and Pb(2+). This novel transformation was done both randomly and at predetermined patterns defined by photolithography to create monolayer sheets composed of different netpoints. All transmetalated sheets are mechanically strong enough to be spanned over 20 × 20 μm(2) sized holes. Density functional theory calculations provide both a model for the molecular structure of an Fe(2+)-based sheet and first insights into how transmetalation proceeds. Such transmetalated sheets with random and patterned netpoints can be considered as two-dimensional analogues of linear copolymers. Their nanoscale synthesis presents an advance in monolayer/polymer chemistry with applications in fields such as surface coating, molecular electronics, device fabrication, imaging, and sensing.

Mapping nanomechanical properties of freshly grown, native, interlamellar organic sheets on flat pearl nacre

We imaged surfaces of freshly grown flat pearl nacre (Haliotis tuberculata) in different stages of growth in seawater using an atomic force microscope (AFM). Characteristic mineral phases of nacre, such as aragonitic stacks of coins, as well as the associated organic sheets, could be detected. Apart from imaging, the acquisition of force volumes on freshly grown organic surface areas on flat pearl nacre was conducted with the AFM. The evaluation of the force volumes with the Hertz–Sneddon model resulted in Young’s moduli in the MPa range. The presented values are considerably smaller than values previously determined from macroscopic tensile tests. This might reflect the anisotropy of the organic nacre layers.

Early Stage Biomineralization in the Periostracum of the ‘Living Fossil’ Bivalve Neotrigonia

A detailed investigation of the shell formation of the palaeoheterodont ‘living fossil’ Neotrigonia concentrated on the timing and manufacture of the calcified ‘bosses’ which stud the outside of all trigonioid bivalves (extant and fossil) has been conducted. Electron microscopy and optical microscopy revealed that Neotrigonia spp. have a spiral-shaped periostracal groove. The periostracum itself is secreted by the basal cell, as a thin dark pellicle, becoming progressively transformed into a thin dark layer by additions of secretions from the internal outer mantle fold. Later, intense secretion of the internal surface of the outer mantle fold forms a translucent layer, which becomes transformed by tanning into a dark layer. The initiation of calcified bosses occurred at a very early stage of periostracum formation, deep within the periostracal groove immediately below the initialmost dark layer. At this stage, they consist of a series of polycyclically twinned crystals. The bosses grow as the periostracum traverse through the periostracal groove, in coordination with the thickening of the dark periostracal layer and until, upon reaching the mantle edge, they impinge upon each other and become transformed into large prisms separated by dark periostracal walls. In conclusion, the initial bosses and the external part of the prismatic layer are fully intraperiostracal. With later growth, the prisms transform into fibrous aggregates, although the details of the process are unknown. This reinforces the relationships with other groups that have the ability to form intraperiostracal calcifications, for example the unionoids with which the trigonioids form the clade Paleoheterodonta. The presence of similar structures in anomalodesmatans and other euheterodonts raises the question of whether this indicates a relationship or represents a convergence. The identification of very early calcification within an organic sheet has interesting implications for our understanding of how shells may have evolved.

Crystal Chemistry of Uranyl Carboxylate Coordination Networks Obtained in the Presence of Organic Amine Molecules

AbstractThree uranyl isophthalates (1,3‐bdc) and two uranyl pyromellitates (btec) of coordination‐polymer type were hydrothermally synthesized (200 °C for 24 h) in the presence of different amine‐based molecules [1,3‐diaminopropane (dap) or dimethylamine (dma) originating from the in situ decomposition of N,N‐dimethylformamide]. (UO2)2(OH)2(H2O)(1,3‐bdc)·H2O (1) is composed of inorganic tetranuclear cores, which are linked to each other through the isophthalato ligand to generate infinite neutral ribbons, which are intercalated by free H2O molecules. The compounds (UO2)1.5(H2O)(1,3‐bdc)2·0.5H2dap·1.5H2O (2) and UO2(1,3‐bdc)1.5·0.5H2dap·2H2O (3) consist of discrete uranyl‐centered hexagonal bipyramids connected to each other by a ditopic linker to form a single‐layer network for 2 or a double‐layer network for 3. The protonated diamine molecules are located between the uranyl–organic sheets and balance the negative charge of the layered sub‐networks. The phase (UO2)2O(btec)·2Hdma·H2O (4) presents a 2D structure built up from tetranuclear units, which consist of two central sevenfold coordinated uranium centers and two peripheral eightfold coordinated uranium centers. The connection of the resulting tetramers through the pyromellitate molecules generates an anionic layerlike structure, in which the protonated dimethylammonium species are inserted. The compound UO2(btec)·2Hdma (5) is also a lamellar coordination polymer, which contains isolated eightfold coordinated uranium cations linked through pyromellitate molecules and intercalated by protonated dimethylammonium species. In both phases 4 and 5, the btec linker has non‐bonded carboxyl oxygen atoms, which preferentially interact with the protonated amine molecules through a hydrogen‐bond network. The different illustrations show the structural diversity of uranyl–organic coordination polymers with organic amine molecules as countercations.

Laser Transmission Welding of CFRTP Using Filler Material

Abstract In the automotive industry the increasing environmental awareness is reflected through consistent lightweight construction. Especially the use of carbon fiber reinforced thermoplastics (CFRTP) plays an increasingly important role. Accordingto the material substitution, the demand for adequate joining technologies is growing. Therefore, laser transmission welding with filler material provides a way to combine two opaque joining partners by using process specific advantages of the laser transmission welding process. After introducing the new processing variant and the used experimental setup, this paper investigates the process itselfand conditions for a stable process. The influence of the used process parameters on weld quality and process stability is characterized by tensile shear tests. The successfully performed joining of PA 6 CF 42 organic sheets using natural PA 6 as filler material underlines the potential of the described joining method for lightweight design and other industrial applications.

A two-dimensional hydrogen bonded organic framework self-assembled from a three-fold symmetric carbamate

A flexible organic sheet spontaneously assembled under mild conditions from a tri-carbamate. By introducing cyclohexyl side chains as 'pillars' between the sheets, a hydrogen bonded organic framework was formed which displayed a capacity for accommodating and releasing guest molecules. The guest size/shape selectivity of the lamellar framework was demonstrated by testing with various guests.

Enhancing Light-Trapping Properties of Amorphous Si Thin-Film Solar Cells Containing High-Reflective Silver Conductors Fabricated Using a Nonvacuum Process

We proposed a low-cost and highly reflective liquid organic sheet silver conductor using back contact reflectors in amorphous silicon (a-Si) single junction superstrate configuration thin-film solar cells produced using a nonvacuum screen printing process. A comparison of silver conductor samples with vacuum-system-sputtered silver samples indicated that the short-circuit current density (Jsc) of sheet silver conductor cells was higher than 1.25 mA/cm2. Using external quantum efficiency measurements, the sheet silver conductor using back contact reflectors in cells was observed to effectively enhance the light-trapping ability in a long wavelength region (between 600 nm and 800 nm). Consequently, we achieved an optimal initial active area efficiency and module conversion efficiency of 9.02% and 6.55%, respectively, for the a-Si solar cells. The results indicated that the highly reflective sheet silver conductor back contact reflector layer prepared using a nonvacuum process is a suitable candidate for high-performance a-Si thin-film solar cells.