Alcohol Matrix Research Articles

A Chiral Cocrystal Strategy Producing Room‐Temperature Phosphorescence and Enhancing Circularly Polarized Luminescence

AbstractThe maintenance of triplet excitons to produce room‐temperature phosphorescence while simultaneously improving the luminescence dissymmetry factor (glum) and photoluminescence quantum yield (PLQY) makes the preparation of circularly polarized room‐temperature phosphorescence (CP‐RTP) materials challenging. Herein, two chiral cocrystals are reported with CP‐RTP using S/R‐1‐(1‐Naphthyl)ethanol (S/R‐1‐nea) as the donor and 1,2,4,5‐Tetracyanobenzene (TCNB) as the acceptor. Simultaneous enhancement of glum and PLQY is accomplished, with the greatest phosphorescence in the PLQY of ≈31% and |glum| of 0.065, which is one of the highest |glum| in cocrystals. Doping two chiral cocrystals into the polyvinyl alcohol (PVA) matrix resulted in polymer films with circularly polarized long afterglow luminescence, indicating the potential for multilevel encryption applications. This study provides a novel approach to achieve the dual improvement of glum and phosphorescence PLQY, and broadens the application prospects of CP‐RTP materials.

Extraction of Lignin from Duabanga grandiflora and its Valorization for Nanocomposite Development with Enhanced Mechanical and UV Shielding Properties

Abstract In this study, we report on extracting lignin (EL) from Duabanga grandiflora (Khukon), an untapped wood source, and its transformation into nano-lignin (NL) to create durable and thermally stable composites. Utilizing ultrasonication, we synthesized spherical lignin nanoparticles with an average size of 8 nm, as verified by High-Resolution Transmission Electron Microscopy (HRTEM). These nanoparticles were integrated into a polyvinyl alcohol (PVA) and guar gum (GG) matrix, resulting in PVA-GG-nano-lignin (PGNL) composites. Polyvinyl alcohol (PVA)-Guar gum (GG) nanocomposite films containing various contents of lignin nano-particles (1, 2 and 3 wt%) were formulated by a simple solvent cast method and cross-linked by adding borax. Addition of 1wt% lignin nanoparticles brought in the composite films with 29.8MPa tensile strength and 139.3% elongation at break. Compared to PVA-GG-lignin (PGL) composites, the PGNL composites exhibited a 59.4% increase in tensile strength and enhanced elongation at break and good thermal degradation properties. Notably, the PGNL composite films were transparent but could shield 99.9% of the UV-A (320-400 nm) and UV-B (280-320 nm) radiations, marking a significant advancement in UV protective materials. Our innovative use of Duabanga grandiflora-derived nano-lignin in a dual-polymer network not only underscores the potential of renewable resources in high-performance applications but also aligns with the principles of a circular bioeconomy by offering a sustainable solution for effective UV protection.

Silicon-Enhanced PVA Hydrogels in Flexible Sensors: Mechanism, Applications, and Recycling

Hydrogels, known for their outstanding water absorption, flexibility, and biocompatibility, have been widely utilized in various fields. Nevertheless, their application is still limited by their relatively low mechanical performance. This study has successfully developed a dual-network hydrogel with exceptional mechanical properties by embedding amino-functionalized polysiloxane (APSi) networks into a polyvinyl alcohol (PVA) matrix. This hydrogel effectively dissipates energy through dense sacrificial bonds between the networks, allowing for precise control over its tensile strength (ranging from 0.07 to 1.46 MPa) and toughness (from 0.06 to 2.17 MJ/m3) by adjusting the degree of crosslinking in the polysiloxane network. Additionally, the hydrogel exhibits excellent conductivity (10.97 S/cm) and strain sensitivity (GF = 1.43), indicating its potential for use in wearable strain sensors. Moreover, at the end of its life (EOL), the sensor waste can be repurposed as an adsorbent material for metal ions in water treatment, achieving the recycling of hydrogel materials and maximizing resource utilization.

Carbon nanostructures in polyvinyl alcohol-based silver nanocomposites for serum albumin concentration sensing

Introducing carbon nanostructures in polyvinyl alcohol (PVA) matrix as strengthening elements by solution dispersion method is already known. Here, the plasmonic sensor surfaces interspersed with carbon nanomaterials are studied for their durable and better sensing capabilities. Carbon quantum dots (CQD) and Multiwall carbon nanotubes (MWCNT) are the carbon nanostructures used in the polyvinyl alcohol-silver nanocomposite to develop plasmonic sensing surfaces. Fiber optic unclad U-bent surfaces are encapsulated in the carbon nanostructure dispersed PVA-silver nanocomposite. The surface is further functionalized with the polyelectrolyte poly(allylamine) hydrochloride (PAH) for better bioconjugation. In the available sensor literature, the evaluation of the sensing layer stability after multiple sensing trials is almost nil. In this work, the sensor surface plasmonic performance after multiple sensing trials is evaluated. The results show that plasmonic biosensors with improved sensing performances can be developed by introducing carbon nanomaterials in PVA-silver nanocomposites. The developed sensor heads are used to sense Bovine Serum Albumin (BSA) concentration changes.

Full range fragmentation simulation of nanoflake filler-matrix composite coatings on a polymer substrate

This paper presents a comprehensive experimental and computational study to explore the damage evolution mechanisms of polymer matrix nanocomposite films consisting of rigid ceramic fillers coated on a polymer substrate. The weight ratio of montmorillonite (MMT) fillers in the polyvinyl alcohol (PVA) matrix ranges from 30 % to 70 %, and these are applied onto a polyethylene terephthalate (PET) substrate. Through experiments, apart from damage behaviors, the water vapor transmission rates are also measured to gain insight into moisture diffusion characteristics with varying weight ratios of fillers. The optimal weight ratio of nanocomposite films consisting of a PVA matrix with MMT fillers can vary depending on the purpose of damage resistance and moisture barrier characteristics. A peridynamic theory is employed to simulate various damage scenarios of bi-layer nanocomposite films. The solution strategy presented incorporates the use of the cut-boundary and finite element methods to reduce substrate thickness and make initial predictions of crack onset strains, respectively, under quasi-static loading conditions. Several damage scenarios are considered for thin and thick PVA films on the PET substrate, as well as weak to strong interfaces between the PET-PVA and PVA-MMT layers. Additionally, different distributions of MMT fillers are also considered by varying the distances between them and inserting inclusions. The peridynamic damage analyses encompass crack initiation, propagation, and final failure stages across a wide range of strains, including various damage modes such as matrix cracking, cracking at the filler-matrix, or matrix-substrate interfaces, leading to the cohesive film cracking and delamination.

Effect of carbon nanotubes and zinc oxide on electrical and mechanical properties of polyvinyl alcohol matrix composite by electrospinning method

In this study, polymer composite nanofibers and thin membranes were synthesized using Carbon Nanotubes (CNTs) and Zinc Oxide (ZnO) as fillers in a Polyvinyl Alcohol (PVA) matrix, aiming to evaluate their electrical and mechanical properties. The composite nanofibers and thin membranes were prepared by incorporating different weight ratios of CNTs and ZnO into the PVA matrix using electrospinning and solution casting techniques, respectively. Solutions were prepared by mixing specific weight ratios of PVA, ZnO, and CNTs, followed by magnetic stirring and ultrasonication for homogenization. Electrospinning was performed at 20 kV with a syringe-to-collector distance of 14.5 cm at flow rate of 2.4 ml/hr. The composites were characterized using FTIR spectroscopy and Scanning Electron Microscopy (SEM). The PVA/5%ZnO/0.5%CNT composite exhibited the highest dielectric constant of 10.3 at high frequencies, while PVA/5%CNT showed the highest capacitance of 31.1 pF at 2 MHz. The maximum AC conductivity of 2.72 × 10− 7S/m was also observed for the PVA/5%ZnO/0.5%CNT composite. Mechanical testing revealed significant improvements in Young’s modulus, stress yield, and load yield, with PVA/5%CNT achieving a Young’s modulus of 387.12 MPa and a stress yield of 6.92 MPa. The addition of ZnO and CNT fillers resulted in enhanced electrical and mechanical properties, making these composites suitable for applications in microelectronic devices and packaging materials.

Activating Ultralong Room-Temperature Phosphorescence of Mono-Ring Arylboronic Acid by Hydrogen Bond for Tunable Afterglow Color and Stimulus Response.

Activating the ultralong room-temperature phosphorescence (RTP) of mono-ring arylboronic acid remains a great challenge, because the capacious free spaces shaped by a rubbery polymeric matrix allow the benzene ring skeleton to freely rotate. Herein, the ultralong RTP in mono-ring arylboronic acid derivatives embedded in a polyvinyl alcohol (PVA) matrix is activated, leveraging enhanced intermolecular and intramolecular hydrogen bonding and activating ultralong RTP. By incorporating diverse PBA derivatives into PVA via click chemistry, 3-aminophenylboronic acid (3A-PBA) doped PVA films showcase the most extended RTP lifetimes (2.24 s) and a high quantum yield (11.2%), alongside rapid and sensitive explosive vapor detection capabilities. These findings not only address the activation challenges of RTP in organic systems by highlighting the crucial role of hydrogen bonding and Förster resonance energy transfer in color tunability, but also mark a significant stride toward overcoming the limitations of current luminescent materials. This work heralds a new era in the development of organic phosphorescent materials, offering a promising strategy for broadening their practical applications and enhancing performance, particularly in environmental monitoring and security.

Flexible Hybrid Ceramic Composite Production From Hemp Oil And Waste Mussels/Egg Shells

Eggshells and mussel shells have become significant sources in the search for natural and renewable raw materials suitable for manufacturing flexible ceramic materials. This study enabled the development of flexible ceramic composites with polyvinyl alcohol (PVA) matrix using eggshell, mussel shell, and hemp oil. Scanning Electron Microscope (SEM) and energy dispersive spectroscopy (EDS) revealed the presence of dust particles obtained from the shells produced in composite films with high Ca content. X-ray diffraction (XRD) showed peaks belonging to calcite and aragonite phases and the prominent peak of PVA at 19.4°. All ceramic composite samples showed characteristic absorption peaks at about 1430, 860, and 710 cm−1 in Fourier Transform Infrared Spectroscopy (FTIR) analysis, which were attributed to the bending vibration and asymmetric stretching of CO32-, confirming the presence of CaCO3 in eggshell and mussel shell powders. The produced composite films have the most dramatic tensile strength of 17.06 MPa, and it has been identified that the strength decreased as the amount of powder increased. While the Shore-A hardness of the composites increased by 3.5 times with the increase in the amount of powder, their swelling rates decreased by 400%. The study sheds light on producing new-generation, eco-friendly, flexible ceramic composite materials.

An adaptive bionic sensor: enhancing ankle joint tracking with high sensitivity and superior cushioning performance

Flexible sensors are renowned for their rapid responsiveness, high flexibility, and outstanding mechanical properties, making them ideal for applications in wearable devices, sports and health monitoring, and human-machine interfaces. To enhance the sensing performance of these flexible sensors, researchers have drawn inspiration from nature, creating various bionic microstructures. However, these structures often manifest in the macroscopic form of thin films, which do little to improve impact resistance and joint protection. In response, this work achieves a highly sensitive and impact-resistant pressure sensor by integrating bionic principles at both micro and macro levels. Specifically, at the micro level, a muscle-like hydrogel system consisting of MXene nanosheets incorporated into the double network of polyvinyl alcohol and sodium alginate matrix is selected. At the macro level, the bionic prototypes of mimosa leaves and durian spikes with good energy absorption structure, together with octopus’ sucker with good adsorption capacity are selected, and the synergistic construction of the three structures is realized through 3D printing methods. The obtained sensor has an appropriate response range, sensitivity and stability. More importantly, the displacement deformation of the hydrogel can be reduced by 91.22%, while its adhesion strength can be increased by 57.5% compared to the unstructured hydrogel. As a proof-of-concept, the proposed bionic flexible sensor can be used to monitor the motion status of the human ankle joint in real-time, thereby assisting users in making real-time judgments on gait health.

Ultralong Room Temperature Phosphorescence Emission From Gels Induced by Multiple Confinement Effects

AbstractThe construction of ultra‐long room temperature phosphorescence (RTP) gels has always been a serious challenge because the dispersing medium would significantly deteriorate their rigidity, resulting in triplet excitons consumption by non‐radiative transitions. In this paper, eutectogel with ultra‐long RTP emission is successfully constructed by rebuilding the damaged rigid system with solvent exchange. Specifically, the formation of cyclic borate via the B─O click reaction between 1,3,5‐tris(4‐phenylboronic acid)benzene (TPPB) and poly(vinyl alcohol) (PVA) matrix is demonstrated to be favorable for RTP emission, with the resulting films possessing an afterglow duration of 26 s and a lifetime of up to 2.92 s. Based on this, deep eutectic solvents (DES)‐based RTP gel is successfully prepared by cyclic freezing‐thawing and solvent exchange of aqueous solution of TPPB functionalized PVA obtained by click reaction. The obtained gel exhibited an afterglow of up to 8 s and RTP lifetime of 902 ms under ambient conditions. Further analyses showed that the introduction of DES reconstructed interactions between polymer chains damaged by water and enhanced the rigidity of the system, thus promoting RTP emission.

Positional Isomerism Toward Tunable Organic Afterglow and Reversible Photoactivation Behavior for Anti‐Counterfeiting and Encryption

AbstractAchieving amorphous polymers with ultralong room‐temperature phosphorescence (RTP), tunable organic afterglow, and reversible photoactivation behavior is highly desirable for practical applications but challenging. Herein, simple positional isomers with three carboxyl groups located in the ortho, meta, and para positions of the triphenylamine skeleton are designed and synthesized. By physically blending with the poly(vinyl alcohol) matrix, these isomers show ultralong RTP properties, among which the meta‐isomer has the longest RTP lifetime (620.1 ms). Theoretical calculations reveal that the more efficient intersystem crossing, the slower radiative decay rate of the lowest triplet excitons, and stronger intermolecular hydrogen‐bonding interactions should be responsible for the superior RTP property of meta‐isomer. Furthermore, the tunable organic afterglow is readily realized via a triplet‐to‐singlet energy transfer process. More impressively, the meta and para isomers exhibit reversible photoactivated ultralong RTP properties after embedding into the rigid poly(methyl methacrylate) matrix. Finally, amorphous and flexible polymer films prepared from these positional isomers show potential applications in advanced anti‐counterfeiting and multilevel encryption through subtly combining ultralong RTP lifetime, tunable organic afterglow, and reversible photoactivation behavior.

Copper selenide as a facile nanomaterial for triboelectric nanogenerator: Self-powered Braille code keyboard

The development of triboelectric nanogenerators (TENGs) for sustainable energy harvesting has garnered significant interest, especially in integrating advanced materials to enhance device performance and exploring applications. Herein, the present study investigates the use of copper selenide (Cu2Se) as a robust material for TENGs fabrication. Cu2Se nanorods are synthesized using a facile hydrothermal method and subsequently embedded in a polyvinyl alcohol (PVA) matrix to form a nanocomposite, which is then utilized as tribopositive film. The procured Cu2Se and nanocomposites with varying filler quantities (0.1, 0.2, 0.4, and 0.8 wt%) are analyzed using powder X-ray diffraction, scanning electron microscopy, dielectric measurements, Fourier transform infrared spectroscopy, and ultraviolet–visible spectroscopy to evaluate their structural, morphological, dielectric, and optical properties, and their impact on TENG performance. Interestingly, the device with 0.2 wt% Cu2Se generated peak-to-peak voltage and current of 394.35 V and 83.45 µA respectively, which is about 2.5- and 41-times higher output compared to pristine PVA-TENG. Integrating Cu2Se as filler enhances charge generation, transfer, and retention, due to increased surface roughness, and ability to facilitate better charge separation within the polymer matrix leading to more efficient energy conversion in TENGs. In practical demonstration, the optimized PVA@ Cu2Se-TENG is employed as a self-powered Braille keyboard to generate electrical signals from mechanical interactions, offering a promising solution for energy-efficient, user-friendly Braille technology. Thus, the current study highlights the synergistic effects of integrating Cu2Se with polymer, resulting in enhanced triboelectric performance for innovative energy harvesting applications and self-powered sensory devices.

Hydrogel Electrolyte with Regulated Water Activity and Hydrogen Bond Network for Ultra‐Stable Zinc Electrode

AbstractQuasi‐solid‐state zinc‐ion batteries (QZIBs) have attracted wide attention due to their excellent dimensional stability and high safety. However, poor ion conduction capabilities, severe dendrite growth, and rampant side reactions still hinder their commercialization. The regulation of the solvation structure of Zn2+ is considered to be an effective method to address these issues. Herein, a hydrogel electrolyte with a regulated solvation structure (HE‐RS) is designed via the combination of tetramethyl urea (TMU) additive and polyvinyl alcohol (PVA) matrix. The hydrophilic ─C═O group of TMU exhibits strong affinity with the PVA chains, improving the mechanical strength of the PVA matrix. The ─N(CH3)2 groups at both ends of TMU exhibit strong hydrophobic characteristics, which leads to local hydrophobicity and decreased water activity. Additionally, abundant oxygen‐containing (electronegative) groups on both PVA and TUM can adsorb Zn2+ and provide sites for Zn2+ transference. Benefiting from these merits, Zn2+ solvation structure and deposition behavior are regulated. Consequently, the Zn||Zn symmetric cell with HE‐RS exhibits a stable cycling life exceeding 2000 h. Moreover, the HE‐RS‐based Zn||NH4V4O10 cell exhibits a capacity retention of 96.4% after 1000 cycles at 2 A g−1.

Incorporating iron oxide nanoparticles in polyvinyl alcohol/starch hydrogel membrane with biochar for enhanced slow-release properties of compound fertilizers

Biochar-based fertilizers show promise in enhancing nutrient utilization and soil health, but their slow-release performance remains a challenge. Herein, hydrogel membranes incorporating iron oxide nanoparticles within a polyvinyl alcohol and starch matrix (Fe/PVA/ST) were synthesized. These membranes were utilized to coat compound fertilizer particles, with biochar powder applied to the outer layer to form what is known as Fe/PVA/ST-BSRFs. The results revealed that Fe/PVA/ST-BSRFs exhibit markedly improved slow-release performance compared to both PVA/ST-BSRFs lacking iron nanoparticles and commercial compound fertilizers. Within a 30-day period, the cumulative leaching ratios of N, P, and K from Fe/PVA/ST-BSRFs with 0.75 % iron content were significantly lower compared to other tested fertilizers, with values of 22.87 %, 34.93 %, and 84.08 %, respectively. Furthermore, the incorporation of iron oxide nanoparticles into the PVA/ST membrane enhanced its swelling and water-retention properties without compromising its biodegradability. Mechanistic investigations revealed that the exceptional slow-release properties of Fe/PVA/ST-BSRFs stem from a combination of nutrient diffusion control outside the membrane and the loose control mechanism of the membrane. Pot tests demonstrated that Fe/PVA/ST-BSRFs effectively promoted the growth of chili plants while ensuring high utilization of N-P-K and improving the nutritional indices of chili fruits. Economic analysis further underscored the promising application prospects of Fe/PVA/ST-BSRFs.

Removal of Textile Dye Using a Low‑Cost Composite Film Based on PVA-Clay: Preparation, Characterization and RSM Optimization

The use of adsorbent materials in powder form presents significant challenges for industrial wastewater treatment due to their poor regeneration after use. Our research described here aimed to prepare a low-cost and eco-friendly film with excellent regeneration capabilities for the efficient removal of Telon Orange dye (TO) from water. The film was fabricated by incorporating a natural clay, DD3, into a poly (vinyl alcohol) (PVA) matrix using the solvent casting method. The prepared film was characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermal gravimetric analysis (TGA) techniques. The characterization results confirmed that the DD3 interacts and disperses within the PVA matrix. The influence of film dose and composition, pH, contact time, and initial concentration were studied in batch adsorption. Response surface methodology (RSM) using the Box-Behnken design matrix was then used to find the best conditions for dye adsorption. An ANOVA analysis approved the proposed quadratic model with a high correlation coefficients (R2 = 0.98). The F-value of the model was 46.39, indicating that the model was significant. The PVA/DD3 composite film achieved a 93.45% efficiency in removing TO dye under optimal conditions. The recyclability studies showed a removal efficiency of 90.13% after five uses of the film, making it suitable for large-scale applications and adaptable for use in water purification systems.

A Dynamic H-Bonding Network Enables Stimuli-Responsive Color-Tunable Chiral Afterglow Polymer for 4D Encryption.

The development of stimuli-responsive and color-tunable chiral organic afterglow materials has attracted great attention but remains a daunting challenge. Here, a simple yet effective strategy through the construction of a dynamic H-bonding network is proposed to explore the multi-color stimuli-responsive chiral afterglow by doping a self-designed chiral phosphorescent chromophore into a polyvinyl alcohol matrix. A stimuli-responsive deep blue chiral afterglow system with a lifetime of up to 3.35 s, quantum yield of 25.0%, and luminescent dissymmetry factor of up to 0.05 is achieved through reversible formation and breakdown of the H-bonding network upon thermal-heating and water-fumigating. Moreover, multi-color stimuli-responsive chiral afterglow can be obtained by chiral and afterglow energy transfer, allowing the establishment of afterglow information displays and high-level 4D encryption. This work not only offers a facile platform to develop advanced stimuli-responsive materials but also opens a new avenue for developing next-generation optical information technology with enhanced functionality and responsiveness.

Facile synthesis of triple‐network organo‐hydrogel for all‐temperature flexible supercapacitors

AbstractA new triple‐network organo‐hydrogel with high anti‐freezing and thermally‐stable performance is prepared for application in all‐temperature flexible supercapacitor. It is composed of boric acid/graphene/polyvinyl alcohol matrix and H2SO4/dimethyl sulfoxide mixing solution. The incorporation of graphene and boric acid into polymer matrix can improve thermal stability and ionic conductivity of organo‐hydrogel. The H2SO4 and dimethyl sulfoxide are key roles for improving anti‐freezing of organo‐hydrogel. The organo‐hydrogel exhibits high ionic conductivity of 1.6 and 3.1 S/m at −80 and 90°C, respectively. As a result, the assembled supercapacitor delivers a high capacitance retention of 84.5% and 113.3% at ultra‐low temperature (−80.0°C) and high temperature (90.0°C), respectively. The work provides a new route to design and prepare flexible supercapacitor with wide temperature range.

The combination of hydrogels and rutin-loaded black phosphorus nanosheets treats rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease characterized by inflammation, joint pain, and cartilage degradation. The fluctuating nature of RA often necessitates long-term oral administration of treatment drugs, which can unfortunately lead to adverse effects such as gastrointestinal discomfort and hepatic and renal dysfunction. Therefore, a percutaneous local delivery method for the release of inflammatory modulators in arthritic joints represents a promising therapeutic approach for RA. In this study, we have developed a unique and innovative therapeutic platform (named BP-Rut@Gel). This hydrogel was formulated by incorporating the drug Rutin (Rut) into Black phosphorus nanosheets (BP) and subsequently integrating them within a Hyaluronic Acid (HA) and Polyvinyl Alcohol (PVA) matrix to create a composite hydrogel. Notably, Secondly, photothermal therapy (PTT) under Near-Infrared Irradiation (NIR) and anti-inflammatory drugs synergistically worked together to efficiently quell inflammation and enhance therapeutic effectiveness. Additionally, toxicity experiments have revealed that our synthesized black phosphorus nanosheet composite hydrogel possesses excellent biocompatibility and significantly reduces the inflammatory response in RA joints. Given these remarkable properties, our BP-Rut@Gel hydrogel held significant promise and demonstrated immense clinical potential for the treatment of RA.

Green synthesized CeO2 nanoparticles-based chitosan/PVA composite films: Enhanced antimicrobial activities and mechanical properties for edible berry tomato preservation.

The current study is intended to enhance unique bioactive and eco-friendly composite films following a simple solvent-casting approach by incorporating cerium oxide nanoparticles (CeO2 NPs) with a chitosan (CS)/polyvinyl alcohol (PVA) matrix. Antimicrobial activity, preservation impact, mechanisms for the edible berry tomatoes and physicochemical properties of the produced films were tested. FTIR, SEM-EDX, XRD, UV–vis spectroscopy and contact angle were used to characterize the films. Incorporated (3.0 wt%) CeO2 NPs practically developed composite film's thermal stability, structural, mechanical, bioactive, antioxidant, barrier and wettability properties. The tomatoes' look, weight loss and stiffness were better preserved after 25 days of storage at room temperature (25 ± 5 °C) when 3.0 wt% CeO2 NPs films were used instead of the original CS/PVA film. CS and CeO2 NPs have unique physiochemical and antibacterial properties. Food packaging extensively investigates the modified films as antimicrobials and preservatives to increase the shelf life of packaged foods, owing to their ability to inhibit gram-positive bacteria (Bacillus cereus and Staphylococcus aureus), gram-negative bacteria (Klebsiella pneumoniae and Pseudomonas aeruginosa), and filamentous fungi (Bipolaris sorokiniana, Fusarium op., and Alternaria sp.). Our findings indicated that the CeO2/CS/PVA composite films could be used as effective wrapping materials for food preservation.

On-demand removable hydrogel film derived from gallic acid-phycocyanin and polyvinyl alcohol for fruit preservation

Postharvest spoilage of fruits accounts for significant losses ranging between 20 %–30 %, leading to considerable resource wastage and economic downturns. The development of an effective fresh-keeping packaging material is of paramount importance. This study introduces an innovative on-demand removable active fruit fresh-keeping film (GPP), created by embedding a GP (gallic acid-phycocyanin) fiber mesh hydrogel with functional properties into a polyvinyl alcohol (PVA) matrix. The resultant GPP hydrogel-based film demonstrates outstanding UV and water vapor barrier capabilities, mechanical stability, resistance to external mechanical stress, universal surface adhesion, antibacterial efficacy, and on-demand removal attributes, while being devoid of potential toxicity hazards. Utilizing grapes and blueberries as representative fruits, it is shown that the GPP hydrogel film significantly preserves the fruits' hardness, pH, total soluble solids content (TSS), and minimizes the rate of weight loss, thereby prolonging the shelf life to 13 days for grapes and 20 days for blueberries at ambient temperature. These results underscore the potential of this hydrogel-based film as an invaluable material for fruit preservation within the food industry.