Acetate Matrix Research Articles

Silicon dioxide incorporated cellulose acetate-mixed matrix membranes for Safranin-O removal from aqueous solutions.

Nanoparticle incorporated-mixed matrix membranes are renowned for their multifaceted advantages, including improved hydrophilicity, elevated solute rejection, enhanced mechanical robustness, and augmented chemical and thermal stability. The inherent hydrophilicity of silicon dioxide (SiO2) nanoparticles, due to silanol groups (Si-OH), along with their high porosity and surface area, renders them an ideal reinforcing filler within polymer matrices, significantly strengthening structural integrity of membranes. In this work, SiO2 nanoparticles were incorporated in a cellulose acetate (CA) matrix to prepare CA/SiO2 adsorptive membranes using phase inversion method. The performance of the membranes was assessed on the removal of Safranin-O (Sf-O) from aqueous solution. The physicochemical characterization of the synthesized membranes was assessed using contact angle, XRD, FE-SEM, EDS, FTIR, TGA, and tensile strength studies. The optimization studies on novel CA/SiO2 membrane revealed that the membrane with 2.5 wt.% of SiO2 in the CA matrix was the best in terms of Sf-O removal (approximately 100% dye removal) when the operating pH, initial dye concentration, and operating pressure were 9, 50 ppm, and 1 bar respectively. It is also found that 2.5 wt.% CA/SiO2 membrane has higher water permeability than other membranes. Incorporating SiO2 nanoparticles into a polymer matrix augments the structural, mechanical, and thermal properties of the resulting membranes while also enhancing water permeability, selectivity, and dye removal efficacy.

Scalable Purification, Storage, and Release of Plant-Derived Nanovesicles for Local Therapy Using Nanostructured All-Cellulose Composite Membranes.

Plant-derived nanovesicles such as bilberries nanovesicles (BNVs) show immense promise as next-generation biotherapeutics and functional food ingredients; however, their isolation, purification, and storage on a large scale remain a challenge. In this study, biocompatible and nanostructured composite all-cellulose membranes are introduced as a scalable and straightforward approach to the isolation of BNV. The membranes consisting of a cellulose acetate matrix infused with anionic or cationic nanocelluloses promoted selective capture of BNVs through electrostatic and size-exclusion-mediated depth filtration. Furthermore, the surface of the composite membrane acted as a storage matrix for BNVs, ensuring their prolonged stability at 4 °C. The BNVs stored in the membrane could be promptly released through elution assisted by low-pressure vacuum filtration or diffusion in liquid media. The morphology, bioactivity, and stability of the extracted BNVs were preserved, and the release rate of BNVs in different cell cultures could be regulated, facilitating their use for local therapy. Consequently, this approach paves the way for the scalable production, purification, and storage of nanovesicles and advances their use in biotherapeutics and functional foods.

Novel polybenzoxazine-based arylidene moiety modified cellulose acetate for enhanced antifouling properties

Marine fouling is a widespread problem in the maritime industry, causing significant damage to equipment and vessels. Polybenzoxazine (PBz) is a resin that is both remarkable and captivating, and it has a wide range of sophisticated uses. Due to their distinctive characteristics, benzoxazines have sparked the interest of scholars globally. However, most benzoxazine resin production and processing depend on petroleum resources, particularly those based on bisphenol A. This study aimed to create new benzoxazine monomers using bio-based raw materials, primarily motivated by the environmental ramifications. The main goal of this study is to synthesize a benzoxazine molecule, specifically (2E,6E)-2,6-bis(3-(2-hydroxyethyl)-3,4-dihydro-2H-benzo[e][1,3]oxazin-6-yl)methylene) cyclohexane-1-one, abbreviated as (CHPE), by employing an arylidene base. Later, the chemical was used as a modifier for the cellulose acetate (CA) matrix to create film samples. The primary objective is to evaluate the effectiveness of these film samples in preventing fouling. The CHPE molecule was produced using a bis(arylidene) cyclohexanone diol and analyzed using Fourier transform infrared (FTIR) and Nuclear magnetic resonance (NMR) spectroscopic techniques, respectively. The films were fabricated by blending various weight proportions. The composition of the (CHPE-CA) films was determined by FTIR analysis, while their morphology was examined using scanning electron microscopy (SEM). The thermal stability of the films was studied using Thermal Gravimetric Analysis (TGA). This study investigated the antifouling properties of polymer sheet compositions containing varying amounts of CA at two different processing temperatures, 180 °C and 200 °C and without curing. The results demonstrated the potential of incorporating CA into the polymer matrix to enhance antifouling performance. Among the polymer compositions tested, the 20% CA composition exhibited the highest percentage reduction in fouling at both processing temperatures, suggesting that a small amount of CA can contribute to effective antifouling properties.

Ultrafiltration membranes for dye wastewater treatment: Utilizing cellulose acetate and microcrystalline cellulose fillers from Ceiba Pentandra

Dye hurts the threat of human health problems and environmental pollution. Microcrystalline cellulose (MCC) based membrane is a good material to be used as an dye separation membrane for having the high hydrophilicity of the membrane. It has been successfully isolated from kapok (ceiba pentandra) with characteristic X-ray diffraction patterns and FTIR absorption peaks, which corresponded to the typical peaks of cellulose. The ultrafiltration membrane was made up of a cellulose acetate matrix created using the phase inversion method. Characterization results indicated that the inclusion of MCC derived from kapok led to a reduction in the contact angle from 65 to 52o, and an increase in membrane porosity from 82 to 85%. In the separation of dye, the composite membrane incorporating MCC filler demonstrated superior performance compared to the membrane lacking MCC, manifesting in an elevated water flux from 43 to 84 L/m².h and methylene blue (MB) rejection from 64 to 99%. The use of MCC as a filler in cellulose acetate membranes can enhance the characteristics and performance of the membrane in MB separation.

An ultrathin and robust single-ion conducting interfacial layer for dendrite-free lithium metal batteries

The practical application of rechargeable lithium metal batteries (LMBs) encounters significant challenges due to the notorious dendrite growth triggered by uneven Li deposition behaviors. In this work, a mechanically robust and single-ion-conducting interfacial layer, fulfilled by the strategic integration of flexible cellulose acetate (CA) matrix with rigid graphene oxide (GO) and LiF fillers (termed the CGL layer), is rationally devised to serve as a stabilizer for dendrite-free lithium (Li) metal batteries. The GCL film exhibits favorable mechanical properties with high modulus and flexibility that help to relieve interface fluctuations. More crucially, the electron-donating carbonyl groups (C=O) enriched in GCL foster a strengthened correlation with Li+, which availably aids the Li+ desolvation process and expedites facile Li+ mobility, yielding exceptional Li+ transference number of 0.87. Such single-ion conductive properties regulate rapid and uniform interfacial transport kinetics, mitigating the growth of Li dendrites and the decomposition of electrolytes. Consequently, stable Li anode with prolonged cycle stabilities and flat deposition morphologies are realized. The Li||LiFePO4 full cells with CGL protective layer render an outstanding cycling capability of 500 cycles at 3 C, and an ultrahigh capacity retention of 99.99% for over 220 cycles even under harsh conditions. This work affords valuable insights into the interfacial regulation for achieving high-performance LMBs.

Solution-processed poly(vinylidene difluoride)/cellulose acetate/Li1+xAlxTi2-x(PO4)3 composite solid electrolyte for improving electrochemical performance of solid-state lithium-ion batteries at room temperature

To enhance energy density and secure the safety of lithium-ion batteries, developing solid-state electrolytes is a promising strategy. In this study, a composite solid-state electrolyte (CSE) composed of poly(vinylidene difluoride) (PVDF)/cellulose acetate (CA) matrix, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt, and Li1.3Al0.3Ti1.7(PO4)3 (LATP) fillers is developed via a facile solution-casting method. The PVDF/CA ratio, LiTFSI, and LATP fractions affect the crystallinity, structural porosity, and thermal and electrochemical stability of the PVDF/CA/LATP CSE. The optimized CSE (4P1C-40LT/20F) presents a high ionic conductivity of 4.9 × 10-4 S cm−1 and a wide electrochemical window up to 5.0 V vs. Li/Li+. A lithium iron phosphate-based cell containing the CSE delivers a high discharge capacity of over 160 mAh g−1 at 25 °C, outperforming its counterpart containing PVDF/CA polymer electrolyte. It also exhibits satisfactory cycling stability at 1C with approximately 90 % capacity retention at the 200th cycle. Additionally, its rate performance is promising, demonstrating a capacity retention of approximately 80 % under varied rates (2C/0.1C). The increased amorphous region, Li+ transportation pathways, and Li+ concentration of the 4P1C-40LT/20F CSE membrane facilitate Li+ migration within the CSE, thus improving the battery performance.

Zinc oxide nanoparticles immobilized on polymeric porous matrix for water remediation

This work proposes a novel approach to producing composite membranes by immobilizing and blending ZnO nanoparticles within a polymer matrix. The focus is investigating how different immobilization techniques impact membrane performance in critical technological applications, including membrane fouling mitigation and photocatalytic degradation. Lab-synthesized ZnO nanostructures were immobilized within a natural cellulose acetate (CA) matrix using a spray coating technique. To ensure comprehensive exploration, CA membranes with 12% and 15% wt polymer concentrations, which demonstrated superior overall performance in previous studies, were cast and prepared. The membranes underwent phase inversion, and a specially prepared ZnO solution was sprayed onto the membrane surface, creating a unique blend of polymer and nanoparticles. This comparative study highlights distinctions between nanomaterial immobilization techniques (mixing and spray coating) while maintaining identical polymer content. Such insights are crucial for both industrial applications and laboratory-scale research. The photocatalytic degradation of the reactive and toxic dye methylene blue (MB) served as a model reaction, employing a UV light module. Results unequivocally demonstrated that, irrespective of the immobilization technique employed, the combination of CA and ZnO nanoparticles significantly enhanced the photocatalytic activity of the membrane in degrading methylene blue (MB). Specifically, the dye concentration decreased from 25 to approximately 8 mg/L for both the spray coating and bulk immobilization methods, resulting in 62% and 69% dye degradation, respectively. These findings underscore the versatility of different immobilization techniques in various aspects of membrane technology. The CA-ZnO composite exhibited efficacy in photocatalytic MB degradation tests, offering promising alternatives for designing polymeric membranes tailored for contaminant removal, particularly in treating textile dye-contaminated aqueous solutions. The exploration of diverse immobilization techniques for nanocomposites presents an exciting avenue for optimization in different membrane technological processes.

Synthesis of stable fluorescent ethylene-vinyl acetate copolymers based on in-situ grafted rare-earth organic complexes and antioxidants through transesterification

The synthesis and application of rare earth organic complexes (REOCs) are gaining attention due to their advantages including low excitation thresholds and high luminescence efficiencies. However, their integration as functional fillers in polymer matrices is constrained by challenges related to poor dispersion and limited stability. This study introduces a novel method for synthesizing stable fluorescent polymers by co-grafting europium (Eu) complexes and the antioxidant 3,9-bis-{1,1-dimethyl-2[β-(3-tert-butyl-4-hydroxy-5-methylphenyl-)propionyloxy]ethyl}-2,4,8,10-tetraoxaspiro[5.5]-undecane (AO-80) onto an ethylene-vinyl acetate (EVA) matrix through an in-situ synchronous grafting strategy, aiming to address these dual challenges of poor dispersion and rapid aging. In this study, Eu complexes characterized by low excitation thresholds and high hexahydrate (EuCl3) and selected ligands - 1,10-phenanthroline (Phen), alpha-thienyl trifluoroacetone (HTTA), and 4-acetoxybenzoic acid (4-ABA). Through transesterifications, the Eu complexes were successfully grafted onto the EVA chain, achieving a uniform dispersion within the EVA matrix to form fluorescent polymers. Furthermore, the incorporation of antioxidant AO-80 as a radical scavenger can significantly mitigate fluorescence attenuation. Through detailed exploration of transesterifications under various conditions, optimal grafting rates of 11.34% for EVA with Eu complexes and 22.87% for EVA with AO-80 were achieved. The synthesized fluorescent polymers of EVA synchronously grafted with Eu complexes and AO-80 have been proven to obtain markedly improved fluorescence stability and aging resistance by outdoor aging tests. Our findings not only validate the in-situ reaction grafting method as an efficient strategy for producing polymer composites with excellent fluorescence stability but also pave the way for future research aimed at overcoming the limitations of REOCs in photovoltaic and agricultural applications.

Copper oxide(I) nanoparticle-modified cellulose acetate membranes with enhanced antibacterial and antifouling properties.

Cellulose acetate membranes exhibit a potential to be applied in hemodialysis. However, their performance is limited by membrane fouling and a lack of antibacterial properties. In this research, copper oxide (I) nanoparticles were fabricated in situ into a cellulose acetate matrix in the presence of polyvinylpyrrolidone (pore-forming agent) and sulfobetaine (stabilising agent) to reduce the leakage of copper ions from nano-enhanced membranes. The influence of nanoparticles on the membrane structure and their antibacterial and antifouling properties were investigated. The results showed that incorporating Cu2O NPs imparted significant antibacterial properties against Staphylococcus aureus and fouling resistance under physiological conditions. The Cu2O NPs-modified membrane could pave the way for potential dialysis applications.

Oleic acid decorated kraft lignin as a hydrophobic and functional filler of cellulose acetate films

The packaging industry has primarily been dominated by single-use, petrochemical-sourced plastic materials despite their short-term use. Their leakage into the ecosystem after their use poses substantial environmental concerns. As a result, compostable and renewable packaging material alternatives are garnering significant attention. Cellulose acetate is a derivative of cellulose that exhibits excellent tensile properties, transparency, melt processability, and intermediate compostability. However, its application in the food packaging industry is limited due to its hygroscopic behavior and lack of dimensional stability. This study investigated using lignin (pristine and esterified) as a functional additive of cellulose acetate. The effect of varying concentrations of pristine kraft and oleic acid functionalized lignin in the cellulose acetate matrix and its effect on the resulting film's mechanical, morphological, viscoelastic, and water barrier properties were explored. Comprehensive characterization of the thermomechanical processed lignin-cellulose acetate sheets revealed reduced moisture absorption, improved UV and moisture barrier, and enhanced tensile properties with melt processability. Overall, the studied films could have appealing properties for food and other packaging applications, thus, serving as eco-friendly and sustainable alternatives to conventional petroleum-derived packing materials.

Structure and functional properties of aluminum hydroxide reinforced bamboo‐derived cellulose acetate composite film for biodegradable packaging

AbstractBiodegradable plastics are gaining popularity as environmentally friendly functional materials. This study focuses on the preparation of aluminum hydroxide (Al(OH)3) reinforced cellulose acetate composite films using a cost‐effective approach. The process involves synthesizing bamboo‐derived cellulose acetate (BDCA), dissolving it in tetrahydrofuran with glycerol as a plasticizer, and incorporating Al(OH)3 particles into the casting solution to reinforce the cellulose acetate film. Analyses on microstructure and characteristics of the films were conducted through various techniques, including scanning electron microscopy (SEM), Fourier transform infrared (FT‐IR) spectroscopy, x‐ray diffraction (XRD), water contact angle measurement, and tensile testing. The results indicate that the Al(OH)3 particles were well‐dispersed in the composite films, leading to a strong interaction with the cellulose acetate matrix. As a result, the prepared composite films exhibited significantly higher tensile strength compared to pure bamboo‐derived cellulose film. Additionally, they demonstrated improved anti‐ultraviolet properties and a lower water vapor transmission rate, despite being more hydrophilic. This method holds significant potential for commercial applications in producing high‐performance cellulose acetate‐based composite films.Highlights Bamboo‐derived cellulose acetate was synthesized through chemical processes. BDCA based composite film reinforced with Al(OH)3 was prepared by casting method. The Al(OH)3 significantly enhance the functional properties of the composite film. Composite films showed good performances for packaging according to the results.

Self-healing and shape-memory polymers based on cellulose acetate matrix

ABSTRACT The creation of self-healing polymers with superior strength and stretchability from biodegradable materials is attracting increasing attention. In this study, we synthesized new biomass-derived cellulose acetate (CA) derivatives by ring-opening graft polymerization of δ-valerolactone followed by the introduction of ureidopyrimidinone (Upy) groups in the polymer side chains. Due to the semicrystalline aliphatic characteristics of the side chain poly(δ-valerolactone) (PVL) and quadruple hydrogen bonds formed by the Upy groups, the stretchability of the resulting polymers was significantly enhanced. Moreover, the shape memory ability and self-healing property (58.3% of self-healing efficiency) were successfully imparted to the polymer. This study demonstrates the great significance of using biomass sources to create self-healing polymers.

The potential application of cellulose acetate membrane for CO2 adsorbent

ABSTRACT Numerous countries have deployed significant efforts to reduce the amount of CO2 released into the atmosphere. Carbon capture and storage is widely regarded as a mitigation technique that can significantly reduce CO2 emissions. A crucial stage in carbon capture and storage is CO2 adsorption using a membrane. Cellulose acetate has demonstrated excellent properties as a membrane material. In this study, we examined the potential of cellulose acetate membrane (CAM) for CO2 gas capture. Two forms of CAM were developed for this study, with and without the addition of glycerol. Scanning Electron Microscope (SEM), Fourier Transform Infrared (FTIR), and CO2 adsorption analyses were used to characterise CAM in numerous ways. The analysis revealed that the addition of glycerol improved the gas adsorption properties of the material. The incorporation of glycerol into the cellulose acetate matrix resulted in an observed augmentation in both the diameter and pore size. The adsorption properties of CO2 are significantly influenced by the microscopic structure of the cellulose acetate membrane. The CAM can be viewed as a possible material for CO2 adsorbers.

ZIF-8 decorated cellulose acetate mixed matrix membrane: An efficient approach for textile effluent treatment

The textile industry is the second largest water-intensive industry and generates enormous wastewater. The dyes and heavy metals present in the textile effluent, even at their lower concentrations, can cause an adverse effect on the environment and human health. Recently, mixed matrix membranes have gained massive attention due to membrane property enhancement caused by incorporating nanofillers/additives in the polymer matrix. This current study examines the efficacy of ZIF-8/CA membrane on dye removal and treatment of real-time textile industry effluent. Initially, ZIF-8 nanoparticles were synthesized using a probe sonicator. The XRD, FT-IR, and SEM analysis confirmed the formation of crystalline and hexagonal facet ZIF-8 nanoparticles. The ZIF-8 nanoparticles were dispersed into a cellulose acetate matrix, and a membrane was prepared using the “phase inversion method.” The membrane was characterized using FT-IR and SEM analysis, which endorse incorporating ZIF-8 into the polymer matrix. Later, the efficacy of the ZIF-8/CA membrane was verified by dye removal studies. The dye removal studies on crystal violet, acid red 13, and reactive black 5 reveal that the membrane is ∼85% efficient in dye removal, and the studies were further extended to real-time textile effluent treatment. The studies on textile effluent prevail that ZIF-8/CA membrane is also proficient in removing chemical oxygen demand (COD) ∼70%, total organic carbon (TOC) ∼80%, and heavy metals such as lead, chromium, and cadmium from textile wastewater and proved to be efficient in treating the textile effluent.

Eosin-Y containing electrospun fibers for optical ammonia sensing based on wavelength shift

Sensors in recent days have been in great demand in industrial zones of simple, low-cost sensors for effectively sensing various gases. This research work develops electrospinning fibers for optical ammonia sensing based on the wavelength shift. The optical sensing fibers were produced approach by the electrospinning technique. The addition of cellulose acetate (CA) matrix with doped Eosin-Y is an NH3 fluorophore. The same light emitting diode (LED) light source was used to excite NH3-sensitive dyes at 380 nm peak wavelength. Display the eosin Y emission spectrum, with a maximum wavelength of 582 nanometers. The observed red emission wavelength shift and fluorescence intensity at 582 nm decreased with increasing concentrations of NH3. The emission spectrum of eosin-Y fluorescence at 582 nanometers is changed with increasing NH3 concentrations ranging from 0 to 500 parts per million. In this work, according to the experiment results, the sensitivity of NH3 sensors is 7.73. Finally, the electrospinning fibers for optical NH3 sensing developed as a result of this research enable effective sensing of NH3 concentrations in practical applications in a variety of fields, including medical and industrial.

Improving cellulose acetate mixed matrix membranes by incorporating hydrophilic MIL-101(Cr)-NH2 nanoparticles for treating dye/salt solution

Mixed matrix membranes were developed by incorporating hydrophilic MIL-101(Cr)–NH2 nanoparticles into a cellulose acetate (CA) matrix, resulting in enhanced hydrophilicity. By enhancing hydrophilicity, mixed matrix membranes were developed to counter the common issue of fouling that occurs when using membranes for the treatment of industrial wastewater. The mixed matrix membrane structures demonstrated impressive stability, with minimal change in water contact angle over a period of 30 days. The incorporation of MIL-101(Cr)–NH2 into the cellulose acetate membrane resulted in a reduction of the water contact angle from approximately 65.1˚ to 50.3˚, improving hydrophilicity. Even with just 1 wt% of MIL-101(Cr)–NH2 added to the cellulose acetate matrix, the pure water flux was significantly increased by 150 % to 68.1 ± 0.87 L/m2h, due to the enhanced hydrophilicity and larger pore size while maintaining a similar level of salt rejection. The prepared membranes exhibited high rejection (>97 %) of Methyl Blue dye through size exclusion mechanism. Additionally, the flux recovery ratio (FRR) improved significantly, increasing from approximately 54 % for the unmodified cellulose acetate membrane to 82 % for the mixed matrix membrane containing 0.2 wt% MIL-101(Cr)–NH2, demonstrating a significant improvement in the antifouling properties of the prepared membrane.

Utilizing a Transparent Conductive Encapsulant to Protect Photoelectrodes during Solar Fuel Formation

Carbon-neutral electricity is rapidly becoming available worldwide as solar and wind technologies advance, but storing energy in chemical bonds will remain a critical need for the transportation sector, as planes and other energy intensive processes will still require liquid fuels. Solar fuels, utilizing sunlight to directly convert CO2 into useful chemicals, are a renewable and net carbon-neutral way to produce needed liquid fuels. However, a common problem with photoelectrochemical solar fuel production is semiconductor degradation from submersion in aqueous environments. An ideal protective layer should 1) prevent solution from reaching the semiconductor, 2) maintain charge transfer to and from the solution, and 3) be transparent to light above the semiconductor band gap. While there presently are protective layer options that meet all three requirements, such as leaky TiO2 and MoS2, they are not easily adaptable to new semiconductor surfaces and/or to new electrochemical reactions. This can make protection difficult for newly developed photoabsorbers and catalytic reaction pairings. In this work, we demonstrate the use of transparent conductive encapsulants (TCEs) to meet these three requirements while also allowing for photoelectrode- and catalysis-agnostic adaptability. TCEs are composed of an ethyl vinyl acetate (EVA) matrix with embedded conductive metal-coated poly(methyl methacrylate) (PMMA) microspheres that can be attached to substrates through a lamination process. First, we characterize the electrochemical behavior of TCE-coated electrodes using the reduction of methyl viologen, demonstrating electrical conduction through the TCE layer. Results from a pinhole detection apparatus suggest the TCE is initially defect free and thus able to prevent solution from reaching the substrate. Then, we perform photoelectrochemical measurements of TCE-covered semiconductors to demonstrate the flexibility of this protection scheme for multiple materials. We also show the results of long-term photoelectrochemical measurements designed to probe the efficacy of TCEs as protective layers. These findings demonstrate that TCEs are an effective protective layer for a variety of photoelectrochemical applications.

Optical Dual Gas Sensor for Simultaneous Detection of Nitric Oxide and Oxygen

This work presents a new optical dual sensor based on PtTFPP-containing electrospun fibers and CsPbBr3 perovskite quantum dots (PQDs) for simultaneous detection of oxygen (O2) and nitric oxide (NO) gases, wherein PtTFPP-containing electrospun fibers for O2 sensing was based on electrospinning process fabricated by platinum(II) meso-tetrakis (pentafluorophenyl) porphyrin (PtTFPP) complex immobilized in cellulose acetate (CA) matrix. CsPbBr3 PQDs were used as NO-sensitive material and coated on the surface of PtTFPP-containing electrospun fibers. Both materials were excited by a UV LED with a central wavelength of 380 nm, and the fluorescence intensities of sensing materials were recorded and analyzed with a spectrometer. The experiment results show that the optical NO and O2 sensors have linear Stern–Volmer plots, and the sensitivities are around 2.7 and 10.7, respectively. The response and recovery times of the optical NO sensor are 71 and 109 s, respectively. For optical O2, response and recovery times are 60 and 65 s, respectively. The optical dual sensor with a new method based on fluorescent dye containing electrospun fibers and coated with CsPbBr3 PQDs has been successfully developed to detect NO and O2 gases simultaneously. The optical dual gas sensor provides great potential for practical applications with low cost and ease of fabrication.

Transparent Conductive Encapsulants for Photoelectrochemical Applications

AbstractUtilizing sunlight to directly perform photoelectrochemical reactions is a promising route to renewable, net carbon‐neutral fuels. However, a common problem with solar fuel production is semiconductor degradation in aqueous environments. An ideal protection layer should (1) prevent solution from reaching the semiconductor, (2) maintain charge transfer to and from solution, and (3) be transparent to light above the semiconductor band gap. While there have been substantial advances toward layers that meet these requirements, they are not easily adapted to new surfaces or new reactions, which can make protection difficult for newly developed photoabsorbers and (photo)electrochemical reaction pairings. In this work, we demonstrate the use of transparent conductive encapsulants (TCEs) to meet these requirements while also allowing for photoelectrode‐ and reaction‐agnostic adaptability. TCEs are composed of an ethyl‐vinyl acetate matrix with embedded conductive metal‐coated microspheres that can be laminated to semiconductors. First, the electrochemical behavior of TCE‐coated electrodes for the reduction of methyl viologen is characterized, demonstrating through‐TCE electrical conduction. Then, photoelectrochemical measurements on TCE‐protected semiconductors demonstrate the flexibility of this protection scheme. Finally, long‐term photoelectrochemical measurements probe the efficacy of TCEs as protection layers. These findings demonstrate the potential of TCEs as adaptable protection layers in various photoelectrochemical applications.

FoodSmarTag: An innovative dynamic labeling system based on pyranoflavylium-based colorimetric films for real-time monitoring of food freshness

A colorimetric pyranoflavylium-based pH-indicator with an improved formulation was obtained and studied as an intelligent label for food freshness monitoring. Pyranoflavylium pigment at 0.2% (w/w) and glycerol at 30% (w/w) were immobilized in a cellulose acetate matrix, and a thin film was obtained by the solvent casting method. The pH-responsive properties of the film were evaluated in solutions at different pH values (pH 4 to 8) and compared with a previous formulation. Film photostability and pigment migration over time were assessed. The label's performance was evaluated using real samples (fish and meat) at controlled conditions (3 °C and modified atmosphere packaging). The results showed that increased pigment concentration visually favored its colorimetric efficacy. Regarding pigment migration and photostability, the label showed to be suitable for application in fresh meat and fish packaging. The best performance was observed for the freshness monitoring of fish samples. The indicator demonstrated high efficacy in detecting spoilage of Atlantic horse mackerel (Trachurus trachurus). After 5 days of storage, freshness parameters exceeded the limit defined by EU regulations, indicating that the fish was unfit for consumption. Simultaneously, the yellow label started to turn purple, effectively indicating the beginning of the spoilage process.