Water Vapor Transmission Research Articles

Introducing PCL-Based Electrospun Nanocomposite Wound Dressings: Synergistic Effects of Curcumin and Reduced Graphene Oxide

ABSTRACT The development of effective wound dressings is critical for enhancing patient outcomes in both acute and chronic wound care scenarios. In this research, electrospun nanofibrous scaffolds were fabricated from poly(ε-caprolactone) (PCL), enhanced with curcumin and reduced graphene oxide (RGO) to optimize their biomedical applications, particularly in wound healing. The resulting scaffolds were rigorously characterized through scanning electron microscopy, contact angle measurements, water uptake capacity, and water vapor transmission rate assays. The biocompatibility of these novel nanofibers was affirmed through MTT assays. Antibacterial tests confirmed the scaffolds’ ability to inhibit both Gram-negative and Gram-positive bacteria, with inhibition zones measuring up to 9.9 mm for S. aureus and 9.2 mm for E. coli. Additionally, scaffolds containing curcumin exhibited significant antioxidant activity, achieving up to 40% radical scavenging efficiency. The study further revealed the scaffolds’ capability for sustained drug release, with an initial burst release within the first 12 hours followed by a gradual release over 168 hours. Overall, the PCL-curcumin-RGO electrospun mats demonstrated considerable potential for biomedical applications, notably in the field of wound dressings, due to their enhanced antibacterial, antioxidant, and biocompatible properties.

Enhancing Hydraulic Lime Mortar with Metakaolin: A Study on Improving Restoration Materials for Historic Buildings.

This study investigates the enhancement of hydraulic lime mortar (HLM) using varying contents of metakaolin (MK) to improve its application in the restoration of historic buildings. Samples from historic structures were analyzed, and the effects of different MK contents on the physical and mechanical properties of HLM were examined. The reaction mechanism and microstructural changes were evaluated using XRD and SEM analysis. The results indicated that increasing MK levels in HLM led to a decrease in fluidity, with fluidity reducing by 4.8% at 12% MK. The addition of MK increased water consumption for standard consistency by 5.4% and shortened the final setting time by 10.2%. MK consumption promoted secondary hydration, enhancing compressive strength by up to 98.1% and flexural strength by up to 55.1%, and increasing bonding strength by 26.9%. The density of HLM improved with MK addition, slightly reducing moisture content by 4.5% and water absorption by 4.6%, while the water vapor transmission properties decreased by 50.9%, indicating reduced porosity. The elastic modulus of the mortar increased significantly from 2.19 GPa to 7.88 GPa with the addition of MK, enhancing rigidity and crack resistance. The optimal blend for restoration materials was found to be 9.0% MK and 25.0% heavy calcium carbonate and was characterized by moderate mechanical strength, enhanced early strength, commendable permeability, minimal risk of cracking, and ease of application. This blend is highly suitable for the rehabilitation of historic structures.

Development and structural characterisation of gelatin‐based sustainable food packaging from turkey (Meleagris gallopavo) skin by‐product

SummaryIn view of the environmental problems resulting from plastic‐based packaging, gelatin film production from alternative, sustainable sources are extremely important. The objective of this study was to utilise a major source of collagen derived from poultry waste to produce and characterise turkey skin gelatin films (TGF). TGFs were produced at different glycerol concentrations (20%, 30% and 40%) via solvent casting technique. TGFs characteristics were also compared with the bovine gelatin films (BGF). The thermal structural development of TGF solutions to form a film network was not affected by the glycerol content in the temperature sweep test. This property was determined earlier and at higher temperatures in TGF (22 °C–23 °C) than in BGF (19 °C). As the glycerol ratio increased, the moisture content increased from 14.80% to 22.46%, while the thickness (36 μm) and density (1.134–1.247 g cm−3) of TGFs remained constant due to the compact structures. The water vapour transmission rates of TGFs and BGF were similar (P >0.05), ranging from 0.48 to 0.53 g mm m−2 h−1 kPa−1. Lower solubility was found for TGF20 (44.78%) and TGF30 (63.59%) films compared to BGF30 (63.59%). TGF20 exhibited the highest tensile strength and lowest elongation at break values. TGF40 and BGF30 demonstrated the highest flexibility and extensibility (P >0.05). In XRD analysis, TG40 demonstrated a less amorphous film structure compared to BG30, since the increased interaction due to glycerol provided a more ordered polymeric structure. TG20 and TG30 showed lower decomposition rates and higher residue levels, indicating their higher thermal stability. Thus, gelatin films based on turkey skin could be the alternative natural biodegradable films with suitable glycerol content for desired mechanical, barrier and thermal properties.

Intelligent Food Packaging: Quaternary Ammonium Chitosan/Gelatin Blended Films Enriched with Blueberry Anthocyanin-Derived Cyanidin for Shrimp and Milk Freshness Monitoring.

Blueberry anthocyanin-derived cyanidin (BAC) was used to prepare a series of responsive food freshness packaging films by compounding it with quaternary chitosan (QC) and gelatin (G). The fundamental properties, pH sensitivity, and functional attributes of the films were examined. The BAC solutions exhibited notable variations in color (from red to pink to violet) under different pH conditions. The incorporation of BAC resulted in improved UV-vis shielding capabilities but compromised the mechanical strength of the films (with tensile strength values from 85.02 to 44.89 MPa, elongation at break from 13.08% to 3.6%, and water vapor transmission rates from 5.24 × 10-9 to 7.80 × 10-9 g m-1 s-1 Pa-1). The QC-G-BAC films, containing 5-15 wt% BAC, exhibited noticeable color changes in acidic/ammonia environments within a short timeframe, easily discernible to the naked eye. Furthermore, the inclusion of BAC significantly enhanced the antioxidant and antimicrobial properties of the films. The addition of 5-15 wt% BAC to QC-G-BAC films could be employed for assessing the freshness of fresh shrimp (from red to dark red) and pasteurized milk (from red to dark earthy yellow). Among them, the total color difference (ΔE) of QC-G-BAC5 film was significantly correlated with the pH, acidity, and total colony count of pasteurized milk (R = 0.846, -0.930, -0.908, respectively). This new concept in smart packaging offers a straightforward and user-friendly freshness indicator.

Tunning the hydrophobic performance and thermal stability of pectin film by acetic anhydride esterification

Pectin, a polysaccharide found in plant cell walls, is characterized by a high abundance of hydroxyl groups and carboxylic acid groups, which results in a strong affinity for water and limits its suitability as a film material. This study aimed to modulate the esterification degree of PEC films by adjusting the concentration of acetic anhydride, and assess the impact of acetic anhydride esterification modification on the properties of the resultant PEC films. The results demonstrated successful grafting of acetic anhydride onto the galacturonic acid ring in the PEC molecule through the esterification process. The hydrophobicity, thermal stability, barrier properties, and mechanical properties of the esterified PEC films were investigated. Among the various concentrations tested, the E-PEC-0.25 film exhibited the highest contact angle of 103.46° and tensile strength of 33.44 MPa, showcasing optimal performance. The E-PEC-0.1 film achieved the highest esterification degree of 0.94 and elongation at a break of 21.11 %. It also exhibited the transparency of 11.66 and the lowest water vapor transmission rate of 0.56 g·mm/(m2·h·kpa). Additionally, TGA and DSC tests revealed enhanced thermal stability of the esterification-prepared films. These findings highlight the potential of acetic anhydride tuning as a promising strategy for optimizing pectin film production.

A flexible and breathable ammonium polyphosphate/chitosan/MWCNT doped PEDOT:PSS coating decorated carbon cloth for high-efficiency flame retardancy and electromagnetic interference shielding applications

There is an urgent need for versatile textiles for different applications due to the rapid development of flexible and wearable electronic devices. However, the poor breathability, high cost, and complex manufacturing processes are still urgent issues to be addressed. In this work, a breathable and flexible carbon cloth (CC) decorated multifunctional coatings (ACMPP) is developed through a facile and scalable coating technology for flame retardancy and electromagnetic interference (EMI) shielding applications. The ACMPP are constructed by incorporating the ammonium polyphosphate/chitosan/multi-walled carbon nanotubes (ACM) composites with core-multi-shell structure into PEDOT:PSS (PP). The low-cost ACM composites demonstrate the promising potential to substitute complex manufacturing processes with an easy electrostatic self-assembly. The as-obtained ACMPP/CC composites display favorable air permeability (69.65 mm·s-1), efficient water vapor transmittance (273.17 kg·m-2·d-1), and high-efficiency flame retardancy (36.8 % of limiting oxygen index), coupled with excellent EMI shielding capacity (59.36 dB in the X band) and shielding stability. The simplicity and scalability of the approach in this work offers a highly cost-performance paradigm to construct next generation flexible textiles for flame retardancy and electromagnetic interference shielding applications.

Production and performance evaluation of chitosan/collagen/honey nanofibrous membranes for wound dressing applications

Persistent bacterial infections are the leading risk factor that complicates the healing of chronic wounds. In this work, we formulate mixtures of polyvinyl alcohol (P), chitosan (CH), collagen (C), and honey (H) to produce nanofibrous membranes with healing properties. The honey effect at concentrations of 0 % (PCH and PCHC), 5 % (PCHC-5H), 10 % (PCHC-10H), and 15 % (PCHC-15H) on the physicochemical, antibacterial, and biological properties of the developed nanofibers was investigated. Morphological analysis by SEM demonstrated that PCH and PCHC nanofibers had a uniform and homogeneous distribution on their surfaces. However, the increase in honey content increased the fiber diameter (118.11–420.10) and drastically reduced the porosity of the membranes (15.79–92.62 nm). The addition of honey reduces the water vapor transmission rate (WVTR) and the adsorption properties of the membranes. Mechanical tests revealed that nanofibers were more flexible and elastic when honey was added, specifically the PCHC-15H nanofibers with the lowest modulus of elasticity (15 MPa) and the highest elongation at break (220 %). Also, honey significantly improved the antibacterial efficiency of the nanofibers, mainly PCHC-15H nanofibers, which presented the best bacterial reduction rates against Staphylococcus aureus (59.84 %), Pseudomonas aeruginosa (47.27 %), Escherichia coli (65.07 %), and Listeria monocytogenes (49.58 %). In vitro tests with cell cultures suggest that nanofibers were not cytotoxic and exhibited excellent biocompatibility with human fibroblasts (HFb) and keratinocytes (HaCaT), since all treatments showed higher or similar cell viability as opposed to the cell control. Based on the findings, PVA-chitosan-collagen-honey nanofibrous membranes have promise as an antibacterial dressing substitute.

3D Wetting Gradient Janus Sports Bras for Efficient Sweat Removal: A Strategy to Improve Women's Sports Comfort and Health.

Developing Janus fabrics with excellent one-way sweat transport capacity is an attractive way for providing comfort sensation and protecting the health during exercise. In this work, a 3D wetting gradient Janus fabric (3DWGJF) is first proposed to address the issue of excessive sweat accumulation in women's breasts, followed by integration with a sponge pad to form a 3D wetting gradient Janus sports bra (3DWGJSB). The 3D wetting gradient enables the prepared fabric to control the horizontal migration of sweat in one-way mode (x/y directions) and then unidirectionally penetrate downward (z direction), finally keeping the water content on the inner side of 3DWGJF (skin side) at ≈0%. In addition, the prepared 3DWGJF has good water vapor transmittance rate (WVTR: 0.0409gcm-2h-1) and an excellent water evaporation rate (0.4704gh-1). Due to the high adhesion of transfer prints to the fabrics and their excellent mechanical properties, the 3DWGJF is remarkably durable and capable of withstanding over 500 laundering cycles and 400 abrasion cycles. This work may inspire the design and fabrication of next-generation moisture management fabrics with an effective sweat-removal function for women's health.

Modifying ASTM E96 to assess water vapour transmission rates of geomembranes at high temperatures

This paper presents a novel methodology for assessing water vapour transmission rates (WVTRs) through geomembranes across a wide temperature range, from 20 °C to 90 °C. This expands upon the existing ASTM E96 standard, limited to temperatures up to 32 °C. The study focused on 1.5 mm thick high-density polyethylene (HDPE) and polyvinyl chloride-ethylene interpolymer alloy (PVC-EIA) geomembranes. The WVTR results—0.15 g/m2h at 25 °C for PVC-EIA and 0.02 g/m2h at 30 °C for HDPE—align closely with values reported in existing literature for similar geomembranes at lower temperatures, validating the methodology proposed in this study. Under elevated temperatures, the WVTR of PVC-EIA increased significantly to 4.7 g/m2h at 90 °C, while HDPE showed a slower increase, reaching only 0.4 g/m2h at the same temperature. This disparity is attributed to polymer composition and behaviour differences under high temperatures. This study's methodology provides a dependable approach for accurately measuring WVTR, including high temperatures relevant to various applications where such data is currently lacking.

Characteristics of Atmospheric Rivers and the Impact of Urban Roof Roughness on Precipitation during the “23.7” Extreme Rainstorm against the Background of Climate Warming

In July 2023, Baoding in Hebei Province experienced unprecedented torrential rainfall, breaking historical records and causing severe flooding. However, our understanding of the multi-scale circulation systems and physical mechanisms driving this extreme precipitation event remains incomplete. This study utilizes multi-source observational data and the Weather Research and Forecasting (WRF) numerical model to conduct a weather diagnosis and numerical simulation of this extreme rainfall event, focusing on the impact of atmospheric rivers (ARS) and urban rooftop roughness on the precipitation process against the background of climate warming. The study found that this extremely heavy rainstorm occurred in the circulation background formed by the factors of subtropical high ectopics, typhoon residual vortex retention, double typhoon water-vapor transmission, and stable high-level divergence. The ARS provided abundant moisture, with its vapor pathway significantly altered following the landfall of Typhoon Doksuri. The interaction between the ARS and the Taihang Mountains was crucial in triggering and intensifying the rainstorm in the foothills. Urbanization significantly affected the distribution of precipitation, with moderate urban roughness enhancing rainfall in and around the city, whereas excessive roughness suppressed it. These results contribute to a deeper understanding of the mechanisms behind extreme precipitation under climate change and provide a scientific basis for improving the forecasting and mitigation of such events.

Mechanically robust superhydrophobic and oleophobic nanofiber membranes with breathability, solvent-resistance, and high-temperature-resistance

Protective materials that can ensure the safety of personnel and equipment in extreme environments have a wide range of application prospects, such as outdoor protective clothing, fire-fighting clothing, etc. However, designing such highly functional materials is still considered a long-standing challenge. Herein, the superhydrophobic and oleophobic fibrous membranes (SOFM) prepared by electrospinning, heat treatment and spraying techniques, endowing the fibrous membranes with good thermal stability, air permeability and outstanding repellence to liquids such as water, oil and low surface energy solvents. The developed SOFM exhibits integrated properties with ethanol intrusion pressure of 0.75 KPa, excellent air permeability of 1.54 mm/s, water vapor transmission rate of 7.99 kg·m−2·d-1, high thermal decomposition temperature of 330 ℃, tensile strength of 9.2 MPa. Therefore, SOFM can effectively protect people and equipment in extreme environments. This work may contribute to the design of fiber materials with higher protection levels in the field of protective clothing.

The Effect of Fibrillation, Semi-Dry Pressing, and Surface Treatment on the Barrier Properties of Water Molecules and Oxygen on Food Packaging Paper.

The characteristics of fiber morphology and paper structure are critical to the barrier properties of food packaging paper. Herein, this study aimed to use pulp fibrillation, paper semi-dry pressing and carboxymethyl starch (CMS) coating to flatten the fibers, which were formed on the paper surface with good barrier properties due to the tight bond between fibers. The results showed that the permeability of paper was reduced by 87.56%, from 81.44 μm/Pa·s to 10.13 μm/Pa·s after the pulp fibrillation treatment (60 °SR). Moreover, semi-dry pressing treatment contributed to decreasing the water vapor transmission coefficient (WVP) by 50.98% to 2.74 × 10-10 g/m·s·Pa, and the oxygen permeation coefficient (OP) decreased by 98.04% to 1.93 × 10-14 cm3·cm/cm2·s·Pa. After coating the paper surface with titanium dioxide (TiO2) and CMS, the WVP of the paper was further reduced to 1.55 × 10-10 g/m·s·Pa, and OP was reduced to 0.19 × 10-14 cm3·cm/cm2·s·Pa. These values were 72.27% and 99.8% lower than those of the original paper, respectively. Therefore, through pulp fibrillation, semi-dry pressing of paper, TiO2 filling, and surface coating with CMS, there is no need to use synthetic polymer surface film-forming agents to achieve the high barrier properties that are required for low water and oxygen molecules permeation in food packaging paper.

Analysis of the flame retardancy effect of boron-containing compound on polyester-cotton blended fabric

Flame-retardant finishing of textile materials is crucial for ensuring human safety and mitigating fire hazards. Though various textile fibers have inherent flame-resistant properties, cotton fiber has a higher affinity to burn. This research focused on developing non-durable FR treatments for cotton-rich polyester-cotton (T/C) blended products economically, using boron-containing compounds. Because of the high melting point use of borax on T/C fabric reduces the fabric's flammability. Boric acid was also used as an auxiliary substrate and Di-sodium hydrogen phosphate dihydrate was used for its cleaning and softening properties. Borax and boric acid create a layer of char when burned and stop the flame. We used the impregnation method for this finishing process. After the chemical finish on different types of T/C fabric, we completed different types of tests like 450 flame retardant, LOI, SEM, breaking strength, drapability, crease recovery, and water vapor transmission tests, and found the desired properties. It increased the flame retardancy and crease recovery properties but the slight reduction of the fabric strength was noticed in case of excessive coating. Water vapor transmission property also reduced gradually with the increase of chemical concentration. Since the chemicals are available in the local market and lower in cost than common FR chemicals, it is more economical.

Preparation and characterization of nanobiocomposite films from sodium caseinate, halloysite nanoclay, and geraniol and application on capsicum (Capsicum annuum) fruits as a case study

Plastics are advantageous in food packaging due to their mechanical strength, flexibility, and low-cost nature. However, their prolonged degradation is not environmentally friendly. Therefore, there is a need to develop alternative food packaging systems. To this end, nature-derived materials such as milk proteins provide a viable solution. In this study, sodium caseinate (SC) based nanobiocomposite films were developed with the incorporation of halloysite nanoclay (HS) and geraniol essential oil (GR). The films exhibited reduced moisture content (from 13.47% ± 0.84%–7.85% ± 0.72%), water solubility (from 20.55% ± 0.80%–9.47% ± 1.06%), water vapor transmission rate (from 84.50 ± 8.06 to 37.33 ± 6.46 g h−1m−2) and increased surface hydrophobicity (contact angle from 53.27 ± 2.97 to 82.70 ± 1.42°) compared to pure SC films. The films were uniform with a semi-crystalline microstructure and an increase in the β-sheet to α-helix ratio was observed due to the increase in the loading concentration of HS and GR. Adding HS and GR improved the mechanical properties, and Young's modulus increased from 69.85 ± 6.12 to 110.12 ± 6.99 MPa. The films demonstrated potent antimicrobial efficacy against Gram-positive Bacillus cereus and Gram-negative Escherichia coli. The SC/HS/GR dispersions could extend the shelf-life of capsicum fruits by reducing weight loss and color change and maintaining firmness. Overall, this research highlights the potential of milk protein-based films incorporated with halloysite and geraniol as sustainable and effective solutions for active food packaging applications.

Preparation and characterization of amidated pectin-gelatin-oxidized tannic acid hydrogel films supplemented with in-situ reduced silver nanoparticles for wound-dressing applications

Wound dressings play a crucial role in protecting injured tissues and promoting the healing process. Traditional fabrication of antibacterial wound dressings can be complex and may involve toxic components. In this study, we developed an innovative hydrogel film (AP:GE@OTA/Ag) composed of amidated pectin (AP), gelatin (GE), oxidized tannic acid (OTA) at varying concentrations, and in-situ reduced silver nanoparticles (AgNPs). FTIR and XRD analyses confirmed that crosslinking occurs via interactions between OTA quinone groups and free amino groups in AP and GE. TEM imaging demonstrated the well-dispersed AgNPs with an average particle size of 58.64 nm, while the TG measurements indicated the enhancement of the thermal stability compared to AP:GE films. The AP:GE@OTA/Ag films exhibited superior fluid uptake ability (90.96 % at 2 h), water retention capacity (91.69 % at 2 h), and water vapor transmission rate (1903.29 g/m2/day), alongside improved tensile strength (38 MPa). Additionally, these films showed excellent cytocompatibility and sustained potent antimicrobial activity against S. aureus and E. coli with low AgNPs loadings of 1.02 ± 0.13 μg/cm2. NIT-1 mouse insulinoma cells demonstrated robust proliferation when cultured with the prepared dressings. These films significantly accelerated wound repair in a skin excision model, indicating their potential clinical applications for wound healing.

Plasma treated‐double layer electrospun fiber mats from thermoplastic polyurethane and gelatin for wound healing applications

AbstractConventional wound treatment options provide a barrier against exogenous microbial penetration but cannot simultaneously provide an antibacterial characteristic and promote healing. However, bioactive dressings can accelerate wound healing and have an antibacterial effect in addition to being able to cover and protect lesions. In this study, double‐layer thermoplastic polyurethane (TPU)‐gelatin fibrous dressings that mimic the epidermis and dermis layers of the skin were fabricated via electrospinning technique. As a bioactive agent, Hypericum perforatum oil (HPO) was utilized to impart antibacterial and therapeutic properties to the dressings. Tannic acid was also used in fiber mat formulations as a cross‐linking agent. Oxygen plasma treatment was applied as a surface activation technique to improve adhesion of TPU and gelation layers. The fiber structure of the mats was revealed by a scanning electron microscopy (SEM) study. Fourier transform infrared (FTIR) spectroscopy was used to demonstrate HPO loading onto the mats. The water vapor transmission rate (WVTR) and fluid absorbency of the mats were compared with some commercial dressings. According to these results, it can be suggested that the mats can be used for moderate to high exudative wounds. All dressings, even the control sample showed antibacterial features against both Staphylococcus aureus and Escherichia coli bacteria due to the tannic acid. In vitro wound healing assays were carried out on the plasma‐treated sample and it was observed that the sample did not negatively affect the migration and proliferation abilities of the cells which are necessary for wound healing. Overall results indicated that the plasma‐treated fibrous mat would be a good candidate as a wound dressing material having an antibacterial character.

Films based on TEMPO-oxidized chitosan nanoparticles: Obtaining and potential application as wound dressings

A series of novel films based on TEMPO-oxidized chitosan nanoparticles were prepared by casting method. Fourier transform infrared spectroscopy (FTIR) was employed to ascertain the chemical structure of TEMPO-oxidized chitosan. The surface morphology of the TEMPO-oxidized chitosan nanoparticles was analyzed by atomic force microscopy (AFM). The physicochemical (area density, thickness, iodine sorption, roughness), functional (moisture sorption, liquid absorption capacity, weight loss upon contact with the liquid, and water vapor transmission rate), antibacterial, and antioxidant properties of films based on TEMPO-oxidized chitosan nanoparticles were also investigated. The physicochemical properties of the films varied widely: area density ranged from 77.83 ± 0.06 to184.46 ± 0.05 mg/cm2, thickness varied between 80.5 ± 1.6 and 200.5 ± 1.6 μm, iodine sorption spanned from 333.7 ± 2.1 to166.4 ± 2.2 mg I2/g, and roughness ranged from 4.1 ± 0.2 to 5.6 ± 0.3 nm. Similarly, the functional properties also varied significantly: moisture sorption ranged from 4.76 ± 0.03 to 9.62 ± 0.11 %, liquid absorption capacity was between 129.04 ± 0.24 and 159.33 ± 0.73 % after 24 h, weight loss upon contact with the liquid varied between 31.06 ± 0.35 and 45.88 ± 0.58 % after 24 h and water vapor transmission rate ranged from 1220.10 ± 2.91to1407.77 ± 5.22 g/m2 day. Despite the wide variations in physicochemical and functional properties, all films showed maximum bacterial reduction of Staphylococcus aureus and Escherichia coli, although they exhibited low antioxidant activity. The results suggest that the films could be effectively utilized as antibacterial wound dressings.

Permeability and barrier layer properties of a woven carbon fibre polymer composite as battery packaging

Carbon fibre reinforced polymer (CFRP) laminates are used in various studies as Li-ion polymer (LiPo) battery packaging. However, their suitability as a packaging material is not well understood. The present study investigates the liquid absorption (water and lithium bis(trifluoromethanesulfonic)imide (LiTFSI) electrolyte immersion tests) and barrier layer properties (water vapour transmission rate (WVTR) and oxygen transmission rate (OTR) tests) of a 200 gsm woven CFRP laminate to assess its suitability as a battery packaging material. This is the first study to show that prolonged immersion in battery electrolyte does not change the mechanical properties of a woven CFRP laminate. Hence, the CFRP laminate may be suitable for structural battery components, such as current collectors and electrodes. However, CFRP should not be used as battery packaging, as OTR and WVTR values of the CFRP laminate were found to be five and one order of magnitudes higher than typical battery pouch materials (i.e. aluminium foil), respectively.

Enhancing Internal and External Stability of Perovskite Solar Cells Through Polystyrene Modification of the Perovskite and Rapid Open‐Air Deposition of ZnO/AlOx Nanolaminate Encapsulation

In this study, the internal and external stabilities of a p–i–n methylammonium lead iodide perovskite solar cell (PSC) are improved. Polystyrene (PS) is introduced into the perovskite layer to form a cross‐linked polymer–perovskite network, which enhances the nucleation and growth of the perovskite grains. Moreover, for the first time, 60 nm thick ZnO/AlOx nanolaminate (NL) thin‐film encapsulation (TFE) is deposited directly on the PSC using an atmospheric‐pressure (AP) spatial atomic layer deposition system operated in AP spatial chemical vapor deposition (AP–SCVD) mode. The rapid nature of AP–SCVD enables encapsulation of the PSCs in open air at 130 °C without damaging the perovskite. The PS additive improves the performance and internal stability of the PSCs by reducing ion migration. Both the PS additive and the ZnO/AlOx NL TFEs improve the external stability under standard test conditions (dark, 65 °C, 85% relative humidity [RH]) by preventing water ingress. The number and thickness of the ZnO/AlOx NL layers are optimized, resulting in a water–vapor transmission rate as low as 5.1 × 10−5 g m−2 day−1 at 65 °C and 85% RH. A 14‐fold increase in PSC lifetime is demonstrated; notably, this is achieved using PS, a commodity‐scale polymer, and AP–SCVD, a scalable, open‐air encapsulation method.

Nano hydrogel with bacterial nanocellulose and bitter almond oil nanoemulsions for enhanced wound healing: In-vivo and in-vitro characterization

Biocompatibility, good mechanical properties, infection prevention, and anti-inflammatory are the requirements of an ideal wound dressing for the care and treatment of skin wounds. In this study, the nanohydrogels as wound dressing, were fabricated by bacterial nanocellulose (BNC), polyvinyl alcohol (PVA), and gellan gum. Bitter almond oil nanoemulsion (BAO-NE) was made with ultrasonic force and incorporated into the nanohydrogels in concentrations of 2, 4, and 6 %. The mechanical and physicochemical analyses such as tensile strength (TS), elongation at break (EB), swelling, water vapor transmission rate (WVTR), degradation, FTIR-ATR, and SEM, and anti-inflammatory, antibacterial, etc. properties of the nanohydrogels were investigated. Also, the wound healing ability was evaluated by in-vivo analyses. The molecular analyses of the expression of genes related to collagen production and inflammation were performed. Increasing BAO-NE concentration enhanced anti-inflammatory and antibacterial activities against Gram-negative and Gram-positive bacteria (P < 0.05). The in-vivo study presented the healing role of nanohydrogels in rat wounds. Real-time PCR results confirmed the anti-inflammatory and healing effects of the films at molecular levels. All the results testify to the promising properties of the fabricated nanohydrogels as a potential wound dressing.