Liquid crystalline polymer pouches for local ­anaesthetic emulsion

In order to enhance the long‐term properties of a high‐pH local anaesthetic drug, emulsion tests were conducted where the emulsion was stored in pouches made of a compression moulded high‐barrier liquid‐crystalline polymer, Vectra A950. The oxygen permeability of the pouch material was too low to be detected at 23°C and 0% relative humidity with the instrument used. The water vapour transmission rate was 0.135 (g.mm/m².day) at 38°C and 100% relative humidity. The emulsion, containing prilocain and lidocain as active substances, was stored in pouches which were sealed by the thermal impulse technique at 260°C for 1.08 s. It was possible to obtain good quality films and good quality seals by optimization of the compression moulding and sealing operations. The concentrations of prilocain and lidocain in the emulsion were studied for 14 weeks at two different temperatures, 40°C and 60°C, and at 100% relative humidity. The decrease in concentration was higher for prilocain (5.4–8.3%) than for lidocain (3.4–3.6%). The loss of the substances from the emulsion was due mainly to adsorption onto the polar surface of the liquid crystalline polymer. Copyright © 2001 John Wiley & Sons, Ltd.     

Enhancing Adhesion of Screen‐Printed Silver Nanopaste Films

The interfacial fracture energy of screen‐printed silver nanopaste films is quantitatively measured, and the fundamental adhesion mechanism is investigated. It is found that the interfacial fracture energy at the Ag film/silicon substrate interface is critically affected by the sintering condition. The sintering temperature tunes the interfacial surface morphology of Ag films and the amount of organic residues at the interface. These factors determine the degree of interfacial toughening between the Ag film and the substrate, which directly affects the adhesion properties. The increased surface roughness of the Ag film with sufficient organic residues leads to a larger interfacial toughening at the film/substrate interface, and subsequently to an enhanced interfacial fracture energy of screen‐printed Ag nanopaste films.     

Practical Approach in Developing Desirable Peel–Seal and Clear Lidding Films Based on Poly(Lactic Acid) and Poly(Butylene Adipate‐Co‐Terephthalate) Blends

In this research, poly(lactic acid) (PLA) blend with poly(butylene adipate‐co‐terephthalate) (PBAT) were selected to fabricate peelable lidding films. In general, blending PLA with PBAT results in hazy films; however, desirable low haze films (<10%) could be achieved in this study by designing proper blend composition and cast film process under optimum conditions. Based on various blends containing PBAT ranging from 15 to 30% by weight, it could be seen that a PBAT/PLA blend of 20/80 showed desired optical and peel–seal property, which had a haze of <10% and low peel strength in an easy‐peel characteristic. It was also observed that not only the blend composition but also the film thickness could influence both optical and peel–seal behaviours because the bulk morphology and surface irregularities of the films could vary by changing films' thicknesses. Thus, cast extruded pristine and PBAT/PLA (20/80) blend films of three different thicknesses (20, 35 and 50 μm) were studied. Peel–seal behaviour and optical properties of these films were examined. An I‐peel test (180°) of films sealed on PLA sheet (thickness of ~350 μm) with different interfacial sealing temperature illustrated failure mechanism of four types, i.e. tearing, partial tearing, cohesive and adhesive failure. Based on this study, the PBAT/PLA of 20/80 wt% films with thickness of 20 μm can be used as easy‐peel lidding film sealed with PLA container. Such PBAT/PLA blend films possess a low haze of ~4% and a low peel strength of 8–10 N/15 mm at a broad range of interfacial sealing temperature of 76–105°C. Copyright © 2017 John Wiley & Sons, Ltd.     

Solution‐Phase Epitaxial Growth of Perovskite Films on 2D Material Flakes for High‐Performance Solar Cells

The quality of perovskite films is critical to the performance of perovskite solar cells. However, it is challenging to control the crystallinity and orientation of solution‐processed perovskite films. Here, solution‐phase van der Waals epitaxy growth of MAPbI₃ perovskite films on MoS₂ flakes is reported. Under transmission electron microscopy, in‐plane coupling between the perovskite and the MoS₂ crystal lattices is observed, leading to perovskite films with larger grain size, lower trap density, and preferential growth orientation along (110) normal to the MoS₂ surface. In perovskite solar cells, when perovskite active layers are grown on MoS₂ flakes coated on hole‐transport layers, the power conversion efficiency is substantially enhanced for 15%, relatively, due to the increased crystallinity of the perovskite layer and the improved hole extraction and transfer rate at the interface. This work paves a way for preparing high‐performance perovskite solar cells and other optoelectronic devices by introducing 2D materials as interfacial layers.     

A Layer‐by‐Layer ZnO Nanoparticle–PbS Quantum Dot Self‐Assembly Platform for Ultrafast Interfacial Electron Injection

Absorbent layers of semiconductor quantum dots (QDs) are now used as material platforms for low‐cost, high‐performance solar cells. The semiconductor metal oxide nanoparticles as an acceptor layer have become an integral part of the next generation solar cell. To achieve sufficient electron transfer and subsequently high conversion efficiency in these solar cells, however, energy‐level alignment and interfacial contact between the donor and the acceptor units are needed. Here, the layer‐by‐layer (LbL) technique is used to assemble ZnO nanoparticles (NPs), providing adequate PbS QD uptake to achieve greater interfacial contact compared with traditional sputtering methods. Electron injection at the PbS QD and ZnO NP interface is investigated using broadband transient absorption spectroscopy with 120 femtosecond temporal resolution. The results indicate that electron injection from photoexcited PbS QDs to ZnO NPs occurs on a time scale of a few hundred femtoseconds. This observation is supported by the interfacial electronic‐energy alignment between the donor and acceptor moieties. Finally, due to the combination of large interfacial contact and ultrafast electron injection, this proposed platform of assembled thin films holds promise for a variety of solar cell architectures and other settings that principally rely on interfacial contact, such as photocatalysis.     

Hydrothermally Oxidized Single‐Walled Carbon Nanotube Networks for High Volumetric Electrochemical Energy Storage

Improving volumetric energy density is one of the major challenges in nanostructured carbon electrodes for electrochemical energy storage device applications. Herein, a simple hydrothermal oxidation process of single‐walled carbon nanotube (SWNT) networks in dilute nitric acid is reported, enabling simultaneous physical densification and chemical functionalization of the as‐assembled randomly‐packed SWNT films. After the hydrothermal oxidation process, the density of the SWNT films increases from 0.63 to 1.02 g cm^?3 and a considerable amount of redox‐active oxygen functional groups are introduced on the surface of the SWNTs. The functionalized SWNT films are used as positive electrodes against Li metal negative electrodes for potential Li‐ion capacitors or Li‐ion battery applications. The functionalized SWNT electrodes deliver high volumetric as well as gravimetric capacities, 154 Ah L^?1 and 152 mAh g^?1, respectively, owing to the surface redox reactions between the introduced oxygen functional groups and Li ions. In addition, these electrodes exhibit a remarkable rate‐capability by retaining its high capacity of 94 Ah L^?1 (92 mAh g^?1) at a high discharge rate of 10 A g^?1. These results demonstrate the simple hydrothermal oxidation process as an attractive strategy for improving the volumetric performance of nanostructured carbon electrodes.     

Controlled Growth of High‐Quality ZnO‐Based Films and Fabrication of Visible‐Blind and Solar‐Blind Ultra‐Violet Detectors

ZnO is a wide‐bandgap (3.37 eV at room temperature) oxide semiconductor that is attractive for its great potential in short‐wavelength optoelectronic devices, in which high quality films and heterostructures are essential for high performance. In this study, controlled growth of ZnO‐based thin films and heterostructures by molecular beam epitaxy (MBE) is demonstrated on different substrates with emphasis on interface engineering. It is revealed that ultrathin AlN or MgO interfacial layers play a key role in establishing structural and chemical compatibility between ZnO and substrates. Furthermore, a quasi‐homo buffer is introduced prior to growth of a wurtzite MgZnO epilayer to suppress the phase segregation of rock‐salt MgO, achieving wide‐range bandgap tuning from 3.3 to 4.55 eV. Finally, a visible‐blind UV detector exploiting a double heterojunction of n‐ZnO/insulator‐MgO/p‐Si and a solar‐blind UV detector using MgZnO as an active layer are fabricated by using the growth techniques discussed here.     

Negative‐Tone Block Copolymer Lithography by In Situ Surface Chemical Modification

Negative‐tone block copolymer (BCP) lithography based on in situ surface chemical modification is introduced as a highly efficient, versatile self‐assembled nanopatterning. BCP blends films consisting of end‐functionalized low molecular weight poly(styrene‐ran‐methyl methacrylate) and polystyrene‐block‐Poly(methyl methacylate) can produce surface vertical BCP nanodomains on various substrates without prior surface chemical treatment. Simple oxygen plasma treatment is employed to activate surface functional group formation at various substrates, where the end‐functionalized polymers can be covalently bonded during the thermal annealing of BCP thin films. The covalently bonded brush layer mediates neutral interfacial condition for vertical BCP nanodomain alignment. This straightforward approach for high aspect ratio, vertical self‐assembled nanodomain formation facilitates single step, site‐specific BCP nanopatterning widely useful for various substrates. Moreover, this approach is compatible with directed self‐assembly approaches to produce device oriented laterally ordered nanopatterns.     

Antimicrobial activity of glucose oxidase‐immobilized plasma‐activated polypropylene films

Antimicrobial enzyme, glucose oxidase (GOX), was covalently immobilized onto amino‐ and carboxyl‐plasma‐activated biorientated polypropylene films (BOPP) via glutaraldehyde and carbodiimide chemistries. N₂‐plasma + NH₃ and N₂‐plasma + CO₂ treatments were utilized to create amino (1.1 nmol/cm²) and carboxyl (0.9 nmol/cm²) groups densities onto the surface of BOPP films. GOX‐immobilized onto amino‐activated BOPP films using 2.5% glutaraldehyde produced higher enzymatic activities than GOX‐immobilized by 0.4% carbodiimide. Further immobilizations were carried out with glutaraldehyde as the coupling agent at temperatures of 4–75°C at pH 5.6 and 7.2. 10 s treatment was sufficient to immobilize GOX at high temperatures in both pH conditions, producing enzymatically active films which remained active over 30 days of storage. GOX covalently immobilized onto BOPP films completely inhibited the growth of Escherichia coli and substantially inhibited the growth of Bacillus subtilis; thus, they may have great potential to be exploited in various antimicrobial packaging film applications. Copyright © 2005 John Wiley & Sons, Ltd.     

Innovative packaging for minimally processed fruits

Novel nanocomposite films for use in the packaging of foods ready for consumption and based on isotactic polypropylene (iPP) filled with innovative calcium carbonate nanoparticles, as well as having spherical and elongated shape and covered with appropriate coating agent able to better interact with the iPP matrix, were prepared and characterized. Morphological, thermal, mechanical and transport characterizations on nanocomposite films were performed. The results evidenced a good dispersion of the nanofiller into the polymeric matrix as well as an increase in mechanical parameters such as modulus. Moreover, a drastic reduction of iPP permeability to both oxygen and carbon dioxide was also recorded. Migration tests evidenced that these nanocomposites are suitable for food packaging applications. Finally, the analysis of some shelf‐life parameters carried out on packaged minimally processed apples showed that these materials are able to preserve for up to 10 days apple slices, limiting oxidation processes and microbiological growth. Copyright © 2006 John Wiley & Sons, Ltd.     

An Ellipsometric Study of the Oxidation of Thin Copper Films in Oxygen

The thermal oxidation of thin copper films deposited on single-crystal silicon was studied by ellipsometry. The optical properties of the oxide layers grown at 420–470 K over a period of up to 150 min were found to vary with layer thickness in a complex manner. The results were analyzed in terms of single- and two-layer models. The oxidation kinetics were shown to follow a parabolic rate law. The apparent activation energies for different stages of oxidation were evaluated with allowance for the self-organization of the interfacial layer.     

铝阳极氧化膜中温封孔工艺研究

铝阳极氧化膜的常温封孔工艺应用广泛,但厚膜封孔比较困难,染色膜封孔时多数染料都会流色,导致封闭质量不佳.为此,研究了一种新型的铝阳极氧化膜中温封孔工艺,并筛选了抑灰剂、封闭盐及其他辅助成分,研制出MS-05中温封孔剂,其分为A型和B型两种产品,其中A型是无氟、无镍的环保型封孔剂,B型是醋酸镍型封孔剂.与日本同类产品进行对比的结果表明:A型不适用于染色膜的封孔,但对无色和电解着色膜具有优异的封孔质量;B型与日本同类产品等效,适应于包括染色膜在内的所有阳极氧化膜,解决了厚膜封孔及染色膜封孔的问题.此外,还对常温封孔和中温封孔两种类型的封孔工艺的优劣做了分析和讨论.     

Physico‐Mechanical Properties of Starch‐Based Films Containing Naturally Derived Antimicrobial Agents

Thermoplastic starch (TPS) films containing relatively low [0.75 ± 0.08% (w/w)], intermediate [1.08 ± 0.04% (w/w)] and high [3.20 ± 0.29% (w/w)] levels of the antimicrobial (AM) agents carvacrol, linalool and thymol were prepared, and their physico‐mechanical and optical properties were evaluated. Addition of these AM agents to TPS film reduced the tensile strength with increasing AM agent content, with a significant effect observed at the highest AM agent concentration. The Young's modulus and elongation at break increased with increasing AM agent concentration, especially at the highest formulation concentration of AM agent. Films having a low or intermediate formulation concentration of AM agent exhibited no significant effect on their water vapour permeability, transparency and thermal properties when compared to the control film. Although scanning electron microscope imaging suggested a significant and progressive change in the surface morphologies of the films with AM agent concentration, the overall effects on the tested properties were not significant. This suggests that the direct incorporation of AM agents into TPS films did not adversely affect the films, particularly at lower AM agent concentrations. Copyright © 2013 John Wiley & Sons, Ltd.     

Infrared and raman spectroscopic studies of optically transparent zirconia (ZrO2) films deposited by plasma-assisted reactive pulsed laser deposition

Plasma-assisted pulsed laser deposited zirconia (ZrO(2)) films were studied by Fourier transform infrared (FT-IR) and Raman spectroscopy for structural characterization and thermal stability in combination with optical characterization by spectroscopic ellipsometry and optical transmission measurements. Only the monoclinic ZrO(2) phase was positively identified from the infrared and Raman spectra of the as-deposited ZrO(2) films, which show excellent optical transparency from the ultraviolet to the near infrared as revealed by optical characterization. The as-deposited ZrO(2) films are free of any SiO(x) interfacial layer when deposited on silicon. The prepared ZrO(2) films exhibit good thermal stability in their structural, optical, and interfacial properties up to 900 °C. Upon annealing above 1100 °C, a silicon oxide interfacial layer forms due to the oxidation of the silicon substrate surface by the oxygen diffused from the oxide film to the silicon substrate at high temperatures.     

Enhanced Dielectric Performance in Polymer Composite Films with Carbon Nanotube‐Reduced Graphene Oxide Hybrid Filler

The electrical conductivity and the specific surface area of conductive fillers in conductor‐insulator composite films can drastically improve the dielectric performance of those films through changing their polarization density by interfacial polarization. We have made a polymer composite film with a hybrid conductive filler material made of carbon nanotubes grown onto reduced graphene oxide platelets (rG‐O/CNT). We report the effect of the rG‐O/CNT hybrid filler on the dielectric performance of the composite film. The composite film had a dielectric constant of 32 with a dielectric loss of 0.051 at 0.062 wt% rG‐O/CNT filler and 100 Hz, while the neat polymer film gave a dielectric constant of 15 with a dielectric loss of 0.036. This is attributed to the increased electrical conductivity and specific surface area of the rG‐O/CNT hybrid filler, which results in an increase in interfacial polarization density between the hybrid filler and the polymer.     

Characterisation of oxidised erbium films deposited on Si(1 0 0) substrates

Thin Er-oxide films were prepared by oxidation of pure Er films grown on glass and Si (p) substrates. The oxide films were characterised by X-ray fluorescence (XRF), X-ray diffraction (XRD), and optical absorption spectroscopy. The XRD analysis of the as-prepared oxide film and the vacuum-annealed film demonstrates the formation of Er₂O₃ phase with about 4.6% of ErO phase, which totally transforms into Er₂O₃ phase under annealing at 600 °C in dry oxygen. Therefore, the phase-structural changes in the prepared Er-oxide films because of the annealing and the long-time storage in vacuum were studied. The constructed Al/Er-oxide/Si MOS devices were characterised by measuring gate-voltage dependence of their capacitance and ac conductance, from which the surface states density (D_it) of insulator/semiconductor interfacial charges and the density of fixed charges in the oxide, were determined, which were within the device-grade range. The ac-electrical conduction and dielectric properties of the of the Er oxide–silicon structure were studied at room temperature. The data of ac conductivity measurements were found to follow the correlated barrier-hopping (CBH) model and the model's parameters were calculated, while the Kramers–Kronig (KK) relations explain the high-frequency dependence of the capacitance.     

Finite-element analysis and experimental study on tensile fatigue behaviour of bitumen–stone adhesion

Tensile fatigue behaviours of bitumen–stone adhesion were investigated using a dynamic mechanics analyser under stress‐controlled mode at two temperatures of 5 and 25°C and various controlled‐stress levels. Failure characteristics including interfacial failure and cohesive failure were examined using image analysis of fracture surfaces. Finite‐element analysis on stress distributions was conducted under different temperatures, film thickness and interfacial bonding conditions. A Coulomb–Mohr like criterion in combination with shear and normal stresses is proposed to deal with the extreme thin adhesive layer, which can be further simplified into an adhesive zone without significant loss of accuracy for stress analysis.     

Free‐Standing,Multilayered Graphene/Polyaniline‐Glue/Graphene Nanostructures for Flexible,Solid‐State Electrochemical Capacitor Application

Graphene/polyaniline multilayered nanostructures (GPMNs) are prepared using a straightforward process through which graphite is physically exfoliated with quaternary polyaniline (PANI)‐glue. This is only accomplished by sonication of the graphite flakes in an organic solvent to form continuous films with PANI. During the sonication, the conductive PANI‐glue is spontaneously intercalated between the graphene sheet layers without deterioration of the sp² hybridized bonding structure. The resultant free‐standing, flexible films are composed of a network of overlapping graphene sheets and are shown to have a long‐range structure. The effects of different PANI content ratios and different interfacial energies (depending on the dispersion solvent) on the morphology and properties of the resulting GPMN are examined. It is found that GPMNs dispersed in water have a maximum specific capacitance of 390 F g⁻¹ in a three‐electrode configuration. Importantly, the unique structural design of GPMNs enables their use as electrode materials for the fabrication of flexible, solid‐state electrochemical capacitors, which show an enhanced performance compared to graphene‐only devices. They exhibit a high specific capacitance of 200 F g⁻¹, a cycling stability with capacitance retention of 82% after 5000 charge/discharge cycles, and, moreover, superior flexibility.     

A Metal–Organic‐Framework‐Based Electrolyte with Nanowetted Interfaces for High‐Energy‐Density Solid‐State Lithium Battery

Solid‐state batteries (SSBs) are promising for safer energy storage, but their active loading and energy density have been limited by large interfacial impedance caused by the poor Li⁺ transport kinetics between the solid‐state electrolyte and the electrode materials. To address the interfacial issue and achieve higher energy density, herein, a novel solid‐like electrolyte (SLE) based on ionic‐liquid‐impregnated metal–organic framework nanocrystals (Li‐IL@MOF) is reported, which demonstrates excellent electrochemical properties, including a high room‐temperature ionic conductivity of 3.0 × 10^‐4 S cm^‐1, an improved Li⁺ transference number of 0.36, and good compatibilities against both Li metal and active electrodes with low interfacial resistances. The Li‐IL@MOF SLE is further integrated into a rechargeable Li|LiFePO₄ SSB with an unprecedented active loading of 25 mg cm^‐2, and the battery exhibits remarkable performance over a wide temperature range from ?20 up to 150 °C. Besides the intrinsically high ionic conductivity of Li‐IL@MOF, the unique interfacial contact between the SLE and the active electrodes owing to an interfacial wettability effect of the nanoconfined Li‐IL guests, which creates an effective 3D Li⁺ conductive network throughout the whole battery, is considered to be the key factor for the excellent performance of the SSB.     

Studies of oxygen uptake on O2 scavengers ­prepared from different iron‐containing ­parent substances

Temperature‐programmed reduction (TPR) measurements were performed for iron oxalates, iron(III) hydroxide (both pure and with additives) and iron(II, III) oxide. On the ground of TPR curves, reduction temperatures of the iron‐containing parent substances were chosen followed by oxygen uptake determination. Comparison of oxygen uptakes points to the use of Fe(OH)₃ and Fe₃O₄ as more advantageous than that of iron oxalates. Co‐precipitation from a mixed solution of iron and manganese salts results in a product which is more resistant to particle agglomeration at elevated temperatures than that obtained by­precipitation from solution of iron salt alone. Copyright © 2002 John­Wiley & Sons, Ltd.