Double-layer Films Research Articles

Endoskopische Unterdrucktherapie

Abstract Introduction Early postoperative reflux (PR) can compromise anastomotic healing after Ivor Lewis esophagectomy (ILE) and poses a risk for aspiration. Anastomotic insufficiency is the most threatening surgical complication. We present the protective method of pre-emptive active reflux drainage (PARD) with simultaneous enteral feeding. We report our experience with this new safety concept in esophageal surgery in a cohort of 43 patients. Materials and Methods For PARD we use a double lumen open porous film drainage (dOFD). To create the dOFD, the gastric tube of a Trelumina probe (Freka®Trelumina, Fresenius) is coated with a double-layered open-pore drainage film (Suprasorb®CNP drainage film, Lohmann & Rauscher) over a length of 25 cm. The dOFD is endoscopically inserted into the tubular stomach intraoperatively after completion of the anastomosis. Continuous negative pressure is applied with an electronic pump (−125 mm Hg). The PR is continuously aspirated completely and the stomach and anastomotic region are decompressed. At the same time, nutrition is delivered via an integrated intestinal tube. Depending on the results of the endoscopic control after 5 days, PARD is either continued or terminated. Results During the observation period (2017–2023), PARD was used in all patients (n = 43) with ILE. The healing rate under PARD was 100% and healing was observed in all anastomoses. No additional endoscopic procedures or surgical revisions of the anastomoses were required. The median duration of PARD was 8 days (range 4–21). We observed problems in the healing of the anastomosis in 20 of 43 patients (47%) for whom we defined endoscopic criteria for at-risk anastomosis. Conclusions Our results suggest that PARD has a strong protective effect on anastomotic healing and may reduce the risk of anastomotic insufficiency. The integrated feeding tube of the dOFD allows early postoperative enteral feeding while simultaneously applying negative pressure. PARD appears to prevent the negative consequences of impaired anastomotic healing.

Enhanced thermal conductivity and electrical insulation by patterned self-assembly of electrospun nanofibers

Low intrinsic thermal conductivity (TC) of polymer materials has severely limited their further applicability in electronic and electrical products. To enhance the TC, a strategy for constructing nanofiller-based thermal conductive networks by patterned self-assembly of electrospun nanofibers was first proposed in this paper. By selecting a regular metal mesh as the collector, the electrostatic field-induced directional deposition of nanofibers was achieved, thereby constructing interconnected heat transfer paths aligned in at least four directions. The in-plane TC of heat-pressed electrospun polyvinylidene fluoride (PVDF) nanofibers with 20 wt% loading of boron nitride nanosheets (BNNSs) can reach 7.27 W/(m·K). Electrical insulation of the PVDF/BNNS composites has also been confirmed, showing high volume resistivity and breakdown strength, which have increased by 460.0 % and 26.6 %, respectively, compared to pure PVDF. Finally, a double-layer composite film with waterproof and easy-cleaning characteristics was prepared for electronic device packaging. This simple and efficient preparation strategy for thermal conductive networks may bring new perspectives to thermal management applications.

Amino carboxymethyl chitosan//dialdehyde starch/polyvinyl alcohol double-layer film loaded with ε-polylysine.

To develop food packaging with good antibacterial activity and mechanical performance, four amino carboxymethyl chitosan (ACC)//dialdehyde starch (DAS) /polyvinyl alcohol (PVA) films were prepared by Schiff base and hydrogen bond interactions for efficient loading and release of ε-polylysine (ε-PL). The effects of the Schiff base reaction on the physicochemical properties of the films were explored based on the different aldehyde group contents in DAS. The ACC//DAS4/PVA film exhibited a tensile strength of 62.5MPa, and the water vapor and oxygen permeability was 8.77×10-3·g·mm/m2·d·kPa and 0.15×103·cm3·mm/m2·d, respectively. By leveraging the Schiff base reaction, the film swelling properties were improved by adjusting the cross-link density, mesh size, and molecular mass between the cross-links. The ACC//DAS4/PVA film could efficiently load ε-PL with a value of 98.44% and long-term release in a food simulant of 10% ethanol at 25°C for 120min. Moreover, the ACC-ε-PL//DAS4/PVA film was successfully used for salmon preservation.

Boosting the Self-Recharging of Polypyrrole/Prussian Blue Electrochromic Device by Potential Difference-Driven Alternative Redox.

Energy-storage electrochromic (EC) devices are a kind of recently developed device integrating energy-saving and energy-storage functions. To minimize energy consumption, a self-rechargeable energy-storage EC device with fast recovery speed is highly desired. Herein, a polypyrrole (PPy)/Prussian blue (PB) double-layer film with a potential difference is initially constructed and fabricated into a fast-recovery self-rechargeable EC device. Due to the existence of potential difference, the reduced PPy can be oxidized by PB, and subsequently Prussian white (the reduced state of PB) can be oxidized by O2 dissolved in electrolyte. Thus, the self-coloration/self-recharging process can be boosted by an alternative redox occurring in the solid/solid/liquid interfaces of PPy/PB/dissolved O2 instead of common solid/liquid interfaces or solutions. After self-recharging for 1 h, 65.0% of the open-circuit voltage and 45.2% of the total capacity can be recovered. Simultaneously, the synergy effect in this PPy and PB system enables a large optical modulation of 63.3% at 800 nm, a high open-circuit voltage of 1.20 V, and a large initial specific capacity of 87.8 mA·h·g-1 at 1.0 A·g-1. The design of double-layer film with a potential difference for boosting the self-coloration/self-recharging process of EC devices provides a new strategy for next-generation self-powered energy-storage EC devices.

Moisture modulated refractive index difference of engineered pore interface for indoor temperature and humidity regulation

Regulation of indoor environments like temperature and humidity consumes enormous energy and brings environmental crises. Therefore, the development of energy-free approaches is critical as it simultaneously improves living comfort and decreases the carbon footprint. Here we report a moisture-modulated strategy to access switchable thermal regulation by tuning solar radiative scattering through manipulation of the refractive index difference (Δn) of a porous surface. This approach is based on a double-layered film containing an upper porous polymer layer and a lower photothermal layer. Via moisture absorption and evaporation, the film performs a reversible thermal switching between solar heating and radiative cooling, allowing efficient space temperature manipulation in the range from + 12.0 to − 8.0 °C. Besides, the moisture-modulated characteristic also offers an opportunity for solar dehumidification by automatically absorbing ambient moisture while mitigating temperature rise. This work bridges a thermal nexus between moisture with solar radiation, while providing a guideline for energy-free indoor environment manipulation.

Highly Transparent Ka-/W-Band Electromagnetic Shielding Films Based on Double-Layered Metal Meshes.

An electromagnetic (EM) wave-shielding film exhibiting high performance in high-frequency bands, such as the Ka- and W-bands, was fabricated by using double-layered metal meshes. The double-layered shielding (DLS) film consists of metallic micromesh and nanomesh electrodes (NMEs) on the upper and lower surfaces of a poly(ethylene terephthalate) (PET) film, respectively. The micromesh electrodes (MMEs) were fabricated such that they possessed a thickness higher than the line width, and they thus exhibited excellent electromagnetic wave-shielding performance in addition to optical transmittance. Moreover, the nanomesh electrodes helped prevent the deterioration of the shielding performance owing to the increase in frequency, which was possible by decreasing the aperture size of the mesh-type electrodes. The shielding effectiveness (SE) of the double-layered metal-mesh film was evaluated by using a shielding measurement system that is optimized for high frequencies. In addition, optical transmittance and flexibility tests were conducted. The results confirm that the double-layered shielding film exhibited a shielding effectiveness of more than 50 dB at an optical transmittance of 90% and a stable bending resistance of up to 5000 cycles at a radius of curvature of 6 mm. Double-layered metal-mesh films with such excellent performance are expected to be widely used in diverse applications such as the automobile, medical, and military industries.

Polycaprolactone/cress seed mucilage based bilayer antibacterial films containing ZnO nanoparticles with superabsorbent property for the treatment of exuding wounds

In this research, a novel double-layer film based on polycaprolactone and cress seed mucilage containing zinc oxide nanoparticles (0.5–2 %) was synthesized using solution casting technique, as an interactive multi-functional wound dressing. The bilayer films were characterized by measuring moisture content, contact angle parameter, porosity, water vapor transmission rate (WVTR), color attributes and opacity, swelling, degradation, mechanical properties, cell viability, and antimicrobial activity, as well as using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The results indicated that the film containing 1.5 % zinc oxide nanoparticles had the best performance, with high swelling ability (3600 %) and 25 % degradation within 24 h of placement in a wound simulator solution. Its mechanical properties, including tensile strength and elongation at break, were 9 MPa and 5.53 %, respectively. In investigating the antimicrobial activity of the optimal film against Escherichia coli and Staphylococcus aureus, the diameter of the inhibition zone was observed to be 39.33 and 42 mm, respectively. Moreover, increasing the number of ZnO-NPs hindered the growth of NIH/3T3 cells, but the 1.5 % ZnO-NP loaded film showed a high percentage of cell viability in 1 day (90 %) and 3 days (93 %), which is suitable for biomedical applications.

The use of active compounds to shape the quality of active double-layer films based on furcellaran intended for packaging salad-dressing – Assessment of utilitarian and storage properties

In order to obtain innovative, high-quality biodegradable packaging, double-layer films based on furcellaran and gelatin, enriched with plant extracts were created. The films were assessed considering their potential utility, applications and environmental impact. The mechanical properties over a period of nine months were studied and it was noted that the passing of time had a beneficial effect on these parameters. The antioxidant properties was also examined, with the highest results obtained using the DPPH and metal chelating activity methods for GE (76.64 % and 9.85 % respectively), while this film showed the lowest FRAP value (5.99 %) compared to the highest obtained for DTE (52.62 %). For the first time, the possibility of using the double-layer active FUR/GEL film as packaging for salad-dressing was evaluated, but no improvement in parameters was observed regardless of the extract used. The environmental impact analysis showed the ability to completely decomposed in vermicompost within several days.

Migration behavior of water molecules and chloride ions at the nanopore scale based on molecular properties under temperature effect

The durability of cement-based materials is closely related to the transmission characteristics of water and chloride ions in the pores of calcium silicate hydrate (C-S-H) gel, especially in the climate conditions with significant temperature difference. The local structure and transport process of water molecules and chloride ions in gel pores are affected by interfacial effects. The unsaturated transport model of sodium chloride solution in C-S-H gel pores is established on the molecular scale, under different temperature and pore size conditions. Divide the regions in the C-S-H gel pore model into internal adsorption zone, external adsorption zone, and free zone. Taking into account the intrinsic mechanisms and molecular properties of water molecules and ions during transport in the C-S-H gel pores, the local structures and dynamic properties of water molecules and ions in the gel pores are quantitatively described. The electrical double layer and the double-layer water film overlap in the 1.5 nm gel pore, the water molecule and the chloride ion are closely arranged. Thus the diffusion coefficient is far lower than others, and is rarely affected by temperature. Considering the changes in the molecule properties of water and ion in different zones in molecular simulation results, a theoretical model of nanopore water and ion migration was established, revealing the migration behavior of water and ions. The results indicate that the steady-state diffusion fluxes of water and chloride ions are positively correlated with the effects of temperature and pore size, and the increasing amplitude of their diffusion fluxes is characterised by a similar phenomenon with that. This research provides a theoretical basis for the mechanism and durability of cement-based materials corroded by water and chloride ions in marine environments.

Endoscopic negative pressure treatment : From management of complications to pre-emptive active reflux drainage in abdominothoracic esophageal resection-A new safety concept for esophageal surgery

Early postoperative reflux (PR) can compromise anastomotic healing after Ivor Lewis esophagectomy (ILE) and poses a risk for aspiration. Anastomotic insufficiency is the most threatening surgical complication. We present the protective method of pre-emptive active reflux drainage (PARD) with simultaneous enteral feeding. We report our experience with this new safety concept in esophageal surgery in a cohort of 43 patients. For PARD we use a double lumen open porous film drainage (dOFD). To create the dOFD, the gastric tube of a Trelumina probe (Freka®Trelumina, Fresenius) is coated with a double-layered open-pore drainage film (Suprasorb®CNP drainage film, Lohmann & Rauscher) over a length of 25 cm. The dOFD is endoscopically inserted into the tubular stomach intraoperatively after completion of the anastomosis. Continuous negative pressure is applied with an electronic pump (-125 mm Hg). The PR is continuously aspirated completely and the stomach and anastomotic region are decompressed. At the same time, nutrition is delivered via an integrated intestinal tube. Depending on the results of the endoscopic control after 5 days, PARD is either continued or terminated. During the observation period (2017-2023), PARD was used in all patients (n = 43) with ILE. The healing rate under PARD was 100% and healing was observed in all anastomoses. No additional endoscopic procedures or surgical revisions of the anastomoses were required. The median duration of PARD was 8 days (range 4-21). We observed problems in the healing of the anastomosis in 20 of 43 patients (47%) for whom we defined endoscopic criteria for at-risk anastomosis. Our results suggest that PARD has a strong protective effect on anastomotic healing and may reduce the risk of anastomotic insufficiency. The integrated feeding tube of the dOFD allows early postoperative enteral feeding while simultaneously applying negative pressure. PARD appears to prevent the negative consequences of impaired anastomotic healing.

Electrophoretic deposition of double-layer ZnO porous films for DSSC photoanode

Electrophoretic deposition of double-layer ZnO porous films for DSSC photoanode

Eco-friendly fabrication of robust flexible superhydrophobic double-layer composite film by a blade coating method

Herein, a flexible superhydrophobic double-layer composite film was fabricated by a simple, low-cost, eco-friendly blade coating method under room temperature. The film can maintain superhydrophobicity after 300 bending and twisting cycles, indicating the outstanding flexibility of the film. The film can easily transfer to objects with complex shape and large curvature by using commercial double-sided tape due to its good flexibility. Moreover, the results of linear friction and pencil hardness tests show that the double-layer composite film still exhibits superhydrophobicity after 200 cycles of linear friction tests and possesses a 2H hardness, demonstrating the good mechanical robustness of the film. It can be expected that this work can provide inspiration for developing novel flexible superhydrophobic film.

Controlled synthesis of Cu-Cr double-layer thin films for oxidative dehydrogenation of propane at low temperature

Controlled synthesis of Cu-Cr double-layer thin films for oxidative dehydrogenation of propane at low temperature

Anodized lamellar Ni-Ni3Si template for electrodeposition of micro-nanostructures

The lamellar Ni-Ni3Si template has the potential for various applications, such as magnetic arrays, layered magnetoelectric materials, electrode materials, and supercapacitors via electrodeposition. However, accurately electrodepositing other materials within the microchannels of the lamellar Ni-Ni3Si template remains a challenge. In this work, the lamellar Ni-Ni3Si template was anodized in 0.1 M oxalic acid (H2C2O4) to achieve accurate deposition of other materials within the microchannels of the lamellar Ni-Ni3Si template. After anodization, the non-anodized and anodized lamellar Ni-Ni3Si templates were subjected to various characterization techniques, including electrochemical impedance spectroscopy, Mott-Schottky analysis, X-ray diffraction and X-ray photoelectron spectroscopy. The study revealed that the optimal anodization potential is 1.2 VSCE, which generated a double-layer passivation film mainly comprised of Ni(OH)2 and SiO2, with a small amount of NiO and Ni2SiO4. Furthermore, cobalt was electrodeposited on non-anodized and anodized lamellar Ni-Ni3Si templates. The results showed that the passive film of the anodized lamellar Ni-Ni3Si template effectively inhibits cobalt nucleation on the surface and sidewalls of the β-Ni3Si sheets and facilitates cobalt deposition within the microchannels. This work provides a novel lamellar metallic template for the electrodeposition of micro-nanostructures.

Impact of Annealing on the Melt Recrystallization of a-PDLA/α-PLLA Double-layered Films

Impact of Annealing on the Melt Recrystallization of a-PDLA/α-PLLA Double-layered Films

PH-responsive double-layer film based on chitosan/curcumin-β-cyclodextrin complex/cinnamaldehyde and zein/alizarin for pork freshness monitoring and maintaining

A pH-responsive double-layer film comprising chitosan (CS), zein (Z), curcumin-β-cyclodextrin complex (Cur- β-CD), alizarin (AL) and cinnamaldehyde (CIN) was developed to detect spoilage and prolong the shelf life of pork. The outer Z/AL is the colorimetric responsive and highly protective outer layer, while the CS/Cur- β-CD/CIN is the fluorescence responsive and functional layer. The CS/Cur- β-CD/CIN-Z/AL film demonstrated excellent barrier properties against oxygen (8.48 × 10-13 g (m s Pa)-1) and water (2.42 × 10-11 g (m s Pa)-1) primarily due to the polar interactions in the Z structure and its hydrophobic nature. The addition of AL and Cur provided the CS/Cur- β-CD/CIN-Z/AL film with pH colorimetric and fluorescence response capabilities, respectively. Furthermore, the inclusion of Cur- β-CD, CIN and AL significantly enhanced the film’s antioxidant and antibacterial properties, with radical scavenging rates of 79.29 % (DPPH) and 89.84 % (ABTS), as well as antibacterial efficiencies of 96.2 % (S. aureus) and 85.78 % (E. coli). To test the effectiveness of the double-layer film, a freshness monitoring and maintenance experiment was conducted on pork stored at 4 °C for 8 days. Various parameters of pork, including surface color, pH value, total volatile bases nitrogen (TVB-N), total viable counts (TVC), thiobarbituric acid reactive substance (TBARS), hardness and springiness, were measured, along with the color and fluorescence intensity (FL) of the film. The shelf life of the pork was extended by at least 2 days compared to the control group, and the pork was considered inedible if ΔE ≥ 12 or FL intensity ≤ 2160. Overall, this food packaging film shows promise in simultaneously monitoring and maintaining the freshness of pork.

Lipid-coated hetero-core optical fiber sensor for wide-range chemical detection

We developed a chemical sensor based on a hetero-core optical fiber structure where lipid films coat a cylindrical cladding. Two lipids were applied to the fiber surface: oleic acid and phosphoric acid di(2-ethylhexyl) ester. Experiments were performed to observe the differential optical loss spectra over the measured spectral region in response to each chemical substance. The oleic acid- and PAEE-coated sensors induced optical losses of approximately 0.4 and 0.2 dB, respectively, for a refractive index difference of 0.0008 between water and quinine. Compared with a conventional hetero-core optical fiber sensor based on surface plasmon resonance, which uses double-layer films of gold and lipid, the proposed sensors scheme showed the different sensitivity to chemical substances and could detect a wide range of chemical substances such as quinine. The response of the proposed sensor was reproducible at concentrations of >0.01 mM. Changing the type of lipid in the film controls the selectivity of chemical substances. The proposed sensor works based on hydrocarbon groups of fatty acids or carboxyl groups that form self-assembled monolayers on the fiber. The exposure of carboxyl groups at the surface of the fatty acids may be involved in the sensor response.

Highly Conductive and Sensitive Wearable Strain Sensors with Metal/Nanoparticle Double Layer for Noninterference Voice Detection.

Human voice recognition via skin-attachable devices has significant potential for gathering important physiological information from acoustic data without background noise interference. In this study, a highly sensitive and conductive wearable crack-based strain sensor was developed for voice-recognition systems. The sensor was fabricated using a double-layer structure of Ag nanoparticles (NPs) and Ag metal on a biocompatible polydimethylsiloxane substrate. The top metal layer acts as a conducting active layer, whereas the bottom Ag NP layer induces channel cracks in the upper layer, effectively hindering current flow. Subsequently, the double-layer film exhibits a low electrical resistance value (<5 × 10-5 Ω cm), ultrahigh sensitivity (gauge factor = 1870), and a fast response/recovery time (252/168 μs). A sound wave was detected at a high frequency of 15 kHz with a signal-to-noise ratio (SNR) over 40 dB. The sensor exhibited excellent anti-interference characteristics and effectively differentiated between different voice qualities (modal, pressed, and breathy), with a systematic analysis revealing successful detection of the laryngeal state and glottal source. This ultrasensitive wearable sensor has potential applications in various physiological signal measurement methods, personalized healthcare systems, and ubiquitous computing.

Color-Switchable Hydroxide Double-Layer Films for Electrochromic Energy Storage Devices

Electrochromic devices have received great attention because of the increment in electrochromic smart window markets for building and vehicles. Recently, electrochromic materials not only enhanced electrochromic performances but also provided additional functions (energy storage, light-emitting diodes, and solar cell). Meanwhile, electrochromic devices are being developed with the goal of large-scale applications such as electrochromic smart windows for building and vehicles, there are still significant needs for reliability of materials and simplify their fabricating processes. In this study, double-layer hydroxide films are reported as energy-storable electrochromic materials with ultrafast kinetics in alkaline electrolyte. Core/shell-like cobalt hydroxide/nickel hydroxide nanofilms deposited within short electrodeposition time have capabilities for multiple color changes (yellow-green-brown) and show extremely fast colored/bleached switching time that are comparable to state-of-the-arts. Furthermore, the cobalt hydroxide/nickel hydroxide nanofilms were indicated high capacitance and rate performance as a battery-type supercapacitors, with higher electrochromic kinetics than those with similar level of capacities for energy storage.

Effects of Selected Plant Extracts on the Quality and Functional Properties of Gelatin and Furcellaran-Based Double-Layer Films

AbstractIn this study, for the first time, double-layer films based on furcellaran and gelatin were obtained, in which the 1st layer of furcellaran was enriched with various plant extracts. The aim of this work was to improve the composition of the developed innovative packaging material by using two layers of biopolymer complexes and analysing the composites to determine the effect of different model plant extracts on the physicochemical properties of the double-layered materials. Furthermore, the hypothesis that positron annihilation lifetime spectroscopy (PALS) could be correlated with gas barrier properties was verified. The addition of plant extracts significantly influenced the physicochemical parameters of the obtained double-layered materials. The lowest solubility was noted in films with the addition of garlic extract (58.40%) and black pepper extract (59.26%) which also had the lowest water content (8.88%). The film with garlic extract also had the lowest oxygen transfer rate (OTR) value after 6 months of storage which is consistent with PALS. The presented data suggest the possibility of correlating PALS results with the gas barrier properties. Tests carried out using this method will facilitate the selection of new potential ingredients when designing packaging materials based on biopolymers, thus, making it possible to obtain new-generation matrices.