A sensing film capable of reporting nitrite levels through two optical pathways was fabricated by embedding NCDs and NED into a PVA matrix. In this sensing film, NED undergoes a Griess-type coupling reaction, resulting in a red color, while the fluorescence of N-CDs decreases as the nitrite concentration increases. These two changes can be used for both quantification and simple visual checks. Under the best conditions, the fluorescence and colorimetric methods had limit of detection of 0.204 mu g/mL and 0.178 mu g/mL, respectively. A visible color change occurred at about 1.5 mu g/mL, allowing for evaluation without instruments. The sensing film was tested on various food samples, such as processed meats, milk products, and vegetable extracts, with results closely matching those from the Griess method. These findings show that this dual-mode platform is practical for quick and sensitive nitrite detection in food analysis.

A dual-layer pH-responsive fluorescent film was developed using hydroxypropyl methylcellulose (HPMC), zinc alginate (ZA), fluorescein isothiocyanate (FITC), and dragon fruit peel extract (DE) for real-time food freshness monitoring. The outer protective layer served as a hydrophobic barrier to reduce moisture interference, while the inner indicator layer acted as a pH-sensitive interface, integrating FITC's fluorescence and DE's visible color change for dual-mode sensing. The film exhibited good thermal stability, antimicrobial activity, and improved hydrophobicity. Optical responses were evaluated across a wide pH range (2.0-12.0), showing stable visible color under ambient light and enhanced fluorescence under 365 nm UV. Upon exposure to ammonia vapor, fluorescence intensity increased linearly from 0 to 1000 ppm (R2 = 0.9895; LOD = 6.73 ppm), while visible color changes became evident at 500-5000 ppm, with R/B and R/G ratios exhibiting strong linearity (R2 = 0.96176 and 0.96747; LODs = 1126 ppm and 958 ppm, respectively). Application trials with pork revealed distinct color changes after 4 days at 25 degrees C or 2 days at 5 degrees C. These results confirm the film's effectiveness for dual-mode, nondestructive, and real-time monitoring of pork freshness.

Cellulose aerogels have garnered significant attention in the thermal insulation sector due to their outstanding thermal insulation properties and eco-friendly characteristics. However, their practical application is limited by their inherent flammability, high-energy consumption and high-cost drying methods (such as freeze drying or supercritical drying). Herein, we innovatively devised a triple cross-linking strategy to prepare thermal insulation cellulose aerogels through a simple and scalable atmospheric pressure drying method. Based on the physical, chemical, and coordinated cross-linking networks formed between bacterial nanocellulose (BC), carboxymethyl cellulose sodium (CMC), phytic acid (PA), trimethoxymethylsilane (MTMS) and ferric ions (Fe3+), the aerogels exhibited excellent mechanical properties (compressive modulus and compressive strength reached 1110 kPa and 340 kPa, respectively) and thermal insulation properties (thermal conductivity was 44.31 mW/mK). Furthermore, the incorporation of PA and MTMS endowed the aerogels with excellent thermal stability, flame retardancy (heat release rate reached 6.06 kW/m2), antibacterial properties, and hydrophobicity (water contact angle reached 128 degrees). These results provided a promising approach for the large-scale production of thermal insulation cellulose aerogels with ideal properties through the atmospheric pressure drying method.

To address the common challenges of leakage and inadequate structural stability in traditional phase change materials (PCMs), this work proposes a multifunctional phase change aerogel fabricated via multi-interactionregulated synergistic directional freezing technology, aiming to advance its application in thermal management. The material, constructed with poly(dopamine)-functionalized mineral-based composites as building blocks, forms a stable hierarchical network with multi-level cavity walls through ordered assembly. Such a layered structure not only effectively encapsulates the phase-change medium to prevent leakage but also endows the aerogel with excellent shape stability and mechanical elasticity. The incorporation of composite phase change components increases interfacial thermal resistance and strengthens phonon scattering effects, conferring the aerogel with exceptional thermal insulation properties (minimum thermal conductivity of 0.039 W/(m & sdot;K)). This material exploits the temperature-buffering capability of PCMs, and combines the thermal insulation of the porous framework with the thermal trapping effect of enclosed air to realize efficient temperature regulation. Therefore, the aerogel performs as an interlayer in firefighter protective masks, delivering reliable flameretardant protection while continuously regulating microenvironmental temperature and exhibiting antimicrobial activity. Furthermore, as an aerogel with highly efficient solar-thermal conversion, it effectively captures solar energy and facilitates passive temperature regulation, representing a novel option for wearable thermal management textiles. This research has developed a thermal management material adaptable to diverse applications, integrating multiple functions including thermal insulation, heat storage, flame retardancy, flexibility, antibacterial activity, and solar-thermal conversion performance. Consequently, it introduces innovative design pathways for engineering advanced composite materials specifically tailored for wearable and protective applications.

A dual-layer film based on hydroxypropyl methylcellulose, zinc alginate, and Hylocereus undatus peel extract was developed for intelligent food packaging applications. The protective layer, prepared by solution casting and surface modification, exhibited enhanced hydrophobicity and barrier performance, with water vapor permeability decreasing from 0.32 × 10⁻10 to 0.097 × 10⁻10 g/m·s·Pa and the water contact angle approaching 90°. The functional layer, fabricated via layer-by-layer assembly, showed pH-sensitive and reversible color responses under simulated spoilage conditions relevant to meat storage. Synergistic intermolecular interactions improved structural integrity, optical transparency, and ultraviolet (UV) shielding, reducing UV transmittance by more than 80

This study reports an eco-friendly sensing film composed of soy protein isolate, zinc alginate, eggplant peel extract, and N-doped carbon dots designed for pork freshness monitoring. The film integrates fluorescence and colorimetric responses to enable dual-mode, pH-sensitive detection and exhibits stable optical behavior across a wide pH range (2.0-12.0). The film also responds linearly to NH3 over a concentration range of 0-1000 ppm (R2 = 0.97528, LOD = 8.68 ppm), with distinct and visible color changes observed at higher concentrations (500-5000 ppm). The film effectively preserved pork quality, as indicated by a 50% reduction in fluorescence intensity at 25 °C after 48 h, and maintained stable fluorescence for up to 36 h at 5 °C prior to spoilage onset. Under 5 °C, it contributed to a 3.9% reduction in pH. This film provides an effective and non-invasive solution for real-time, on-site meat freshness assessment and food waste reduction.

Wood-inspired aerogels with exceptional insulation properties address the global challenge of building energy consumption. Inspired by the structure of natural wood, these wood-inspired aerogels with directional channel structures were prepared using polyvinyl alcohol, phytic acid and sodium metasilicate. This was achieved by combining the directional freezing technology with the dual crosslinking strategy. Based on the strategies of physical crosslinking and chemical thermal crosslinking, these wood-inspired aerogels exhibited excellent mechanical properties in axial direction (compressive strength and compressive modulus reached as high as 6.18 MPa and 23.06 MPa, respectively). Concurrently, the directional channel structure with high interfacial thermal resistance endowed them with excellent insulation properties in axial direction (thermal conductivity reached as low as 45.21 mW/mK). Moreover, the incorporation of phytic acid and sodium metasilicate components endowed the wood-inspired aerogel with excellent thermal stability, flame retardant and antibacterial properties (antibacterial rates against Staphylococcus aureus and Escherichia coli reached 68.29 % and 46.25 %, respectively). These characteristics make them a promising insulation material in the field of energy-efficient buildings.

Biomass aerogels are emerging as green and sustainable materials. Researchers have shown growing interest in their development and practical applications. Among them, cellulose aerogels have demonstrated strong potential in thermal insulation, tissue engineering, and building components. In this study, we used gelatin (G), cellulose nanofibers (CNF), and phytic acid (PA) as raw materials. We fabricated a biomass aerogel with an anisotropic structure through directional freezing and freeze-drying. The resulting aerogel forms a double cross-linked network. Hydrogen bonding and electrostatic interactions stabilize this network. The aerogel exhibits excellent mechanical performance. It also provides effective thermal insulation. In addition, it shows good flame retardancy and antibacterial activity. The aerogel developed in this research is composed of biomass materials with low cost, abundant sources, and a simple preparation process, providing a solid foundation for replacing traditional thermal insulation materials and addressing the current energy crisis.

Biomass aerogels have emerged as promising green building insulation materials owing to their unique porous structure and sustainability. Nevertheless, their practical applications are constrained by poor fire resistance and mechanical stability. In this study, lightweight biomass aerogels (CS) based on sodium carboxymethyl cellulose (CMC) and sodium alginate (SA) were constructed, and graphene oxide (GO) was further introduced to reinforce the framework (CSG). Subsequently, polyaniline (PANI) was coated on the surface of the aerogel as a conductive shell layer by in situ polymerization to form a core-shell aerogel (CSGP) with fire safety and intelligent fire warning capability. Benefiting from the multiple interactions between biomass components, GO, PANI and Ca2+, CSGP core-shell aerogel exhibits a hierarchical porous crosslinked network, and at the same time possesses higher compressive strength (8.36 MPa), thermal insulation property (31.36 mW/(m & sdot;K)) and water resistance (32 days) than CS and CSG aerogels. In fire simulation tests, CSGP aerogel displays excellent flame retardancy (limiting oxygen index up to 49%, peak heat release rate as low as 31.37 kW/m2), owing to the dense physical barrier created by the PANI/GO composite layer. Furthermore, leveraging thermal reduction behavior of GO coupled with charge transport enhancement of PANI enable an ultra-fast fire warning response (1.3 s), crucial for emergency evacuation. This work establishes an innovative strategy for the integrated multifunctional design of biomass aerogel for mechanics-fire protection-smart warning, while promoting their potential application in the field of intelligent buildings.

In this study, we introduced an innovative method by incorporating 1-butyl-3-methylimidazolium chloride (BmimCl) as a versatile component and fine-tuning the mixture of chitosan, BmimCl, and cyanidin cation (Anth) to create pH-responsive smart films for food freshness. Owing to the dual functionality of BmimCl, it served as a plasticizer as well as enhanced the film’s capacity to display a broader spectrum of visible color changes. The material properties of chitosan films containing BmimCl and Anth at varying concentrations were characterized using FTIR, XRD, mechanical test, TGA, UV-vis and pH sensitivity. The combined results indicate that the chitosan-based pH-responsive smart film possessed excellent mechanical properties, great thermal stability, high light transmission, and a broad pH sensitivity. pH-responsive films were used for real-time freshness monitoring of freshwater shrimps, sterilized milk, and hairtails. Results revealed that BmimCl disrupts the hydrogen bond network of chitosan molecules. The films exhibit a transition from green to red as the food turns from fresh to spoiled, effectively demonstrating their capability to monitor freshness.

With the continuous improvement of living standards, the development of eco-friendly rigid polyurethane foam (RPUF) materials with excellent flame retardancy, thermal insulation, and outstanding mechanical strength has become an urgent challenge. This study presented an innovative strategy using lignin as a mechanical reinforcement and flame-retardant synergist, combined with DMMP and EG as highly efficient flame retardants. Furthermore, the incorporation of a silica aerogel coating via surface post-treatment significantly enhanced the flame retardancy of the composite. Compared to neat RPUF, the Ct-RPUF/L/FR composites exhibited an increased LOI of 25.3 %, a delayed ignition time of 6.0 s, and reductions in total heat release (THR) and total smoke production (TSP) to 8.6 MJ/m2 and 2.11 m2, respectively, while achieving the UL-94 V-0 rating, thereby minimizing fire hazards. Additionally, the compressive strength of the composite improved from 132.4 kPa for neat RPUF to 178.3 kPa, with a thermal conductivity of only 30.11 mW/(m·K), maintaining comparable thermal insulation performance to neat RPUF. Moreover, the evidence provided by the Life Cycle Assessment (LCA) indicated that the fire-retardant strategy used in this study resulted in lower environmental impact (EI) compared to traditional fire-retardant methods. This study highlighted the synergistic effects of lignin, flame retardants, and silica aerogel, providing new opportunities for the development of advanced RPUF materials with enhanced fire safety and durability, suitable for practical applications.

In this study, we examined the plasticizing effects of 1-butyl-3-Methylimidazolium Chloride (BmimCl), glycerol, and their combination on chitosan (CS) films. Additionally, we examined the effect of plasticizers for chitosan films structure and physicochemical properties of CS films by FTIR, XRD, SEM and mechanism of action of plasticizers on the structure of CS films. The results indicated that the interaction between BmimCl and chitosan is mainly ionic interaction and hydrogen bonding, while the interaction between glycerol and CS is mainly hydrogen bonding. The utilization of a 1:1 mixture of BmimCl and glycerol as a plasticizer exhibits a synergistic impact on the film samples. In dry conditions, the elongation at break of the CS/BmimCl0.5/Gly0.5 film reached 17.47 %, representing a 33 % and 78 % increase compared to the CS/BmimCl and CS/Gly films, respectively. In moist environments, the mechanical strength of CS/BmimCl0.5/Gly0.5 film was significantly enhanced to 35.09 MPa compared to the CS/BmimCl and CS/Gly films. Notably, the elongation at break of the films remained at 37.05 %, without compromising their flexibility properties.

Sorption-based atmospheric water harvesters (SAWH) provide a promising solution to the world's freshwater shortage problems. Inspired by the transpiration of wood, photothermal aerogels with directional ordered pathways were prepared using directional freezing technology. More importantly, the ultra-hygroscopic lithium composite (LC) converted from lithium chloride (LiCl) was loaded on these aerogels to perfectly solve the deliquescence and agglomeration problems after desorption, resulting in developing pectin/carbon nanotubes/ultra hygroscopic lithium composite (P/CNTs/LC) aerogels. Due to the ordered pathway structure of the pectin-based skeleton and the excellent hygroscopicity of LC, the aerogel exhibited significant water adsorption performance over a wide relative humidity (RH) range. COMSOL Multiphysics simulations and ANSYS predictions further revealed the intrinsic mechanism of the water adsorption kinetics, confirmed that water vapor transport in the ordered pathway structure was much faster than that in the disordered pathway structure. The adsorbed water can be quickly and completely desorbed under solar radiation, and remained stable after 60 adsorption/desorption cycles. The aerogel achieved continuous dehumidification and freshwater production (1.29 L·kg-1·day-1), demonstrating its potential for practical application. Our design offered a promising strategy for preparing high-performance SAWH for dehumidification and water harvesting applications.

Pectin and sodium alginate (SA) were mixed to form composite films using the casting method. Antibacterial packaging films (pectin/ZA) were obtained by a simple ion exchange method with a pectin/SA blend film. The effect of Zn2⁺ on the pectin/SA blend in terms of structural, morphological, thermal, physical, and mechanical properties, as well as antibacterial activity, was investigated in detail. The FT-IR, XRD, and XPS results indicated that Zn2⁺ was successfully introduced into the pectin/SA blend film. Additionally, SEM images exhibited the uniform incorporation of Zn2⁺ into the pectin/SA blend film. Moreover, the blend film of pectin and alginate improved its thermal properties, mechanical properties, and water resistance compared to the pure pectin film. Furthermore, the pectin/ZA blend film had significant antimicrobial activity against S. aureus and E. coli, revealing its potential application in food packaging.

A fully natural and biodegradable film (MC5/ZA5-DE3

This study presents the development of a novel multifunctional smart packaging film designed to enhance food freshness and possess ammonia-sensing capabilities. The film was fabricated using hydroxypropyl methylcellulose (HPMC) and zinc alginate (ZA), incorporating dragon fruit peel anthocyanins (DE) as pH-sensitive dyes. A hydrophobic layer composed of stearic acid and nano-silica (0.2 g SiO2 in 1.5 mL solution) was uniformly spin-coated onto the HPMC/ZA/DE film surface and further modified via chemical vapor treatment to improve water resistance. The resulting HPMC/ZA/DE/SiO2 film demonstrated excellent physical properties, including a high-water contact angle of 116.9°, indicating strong hydrophobicity and effective UV shielding. The film exhibited significant antibacterial activity, achieving 99.99

Lignin-based nanofibers (LNFs) were fabricated via electrospinning using a mixture of lignin and polyvinyl alcohol (PVA) as the spinning solution. Next, the LNFs were sequentially subjected to homogeneous shearing, freeze-drying, in-situ thermal cross-linking, and thermochemical vapor deposition involving treatment with organosilanes to obtain ultralight, mechanically robust, thermal-insulated, and superhydrophobic LNF aerogels (LNFAs). Careful adjustment of the LNF content aided in precise control and optimization of the network structure, density, and porosity of the obtained LNFAs, which ultimately affected their compressive strength and thermal conductivity (25.46 ± 1.32 to 31.06 ± 0.09 mW⋅m-1⋅K-1). Moreover, the lignin content in LNFs also affected the nanofiber diameters, thereby regulating the compressive strength of LNFAs (3.40 ± 0.17 to 4.91 ± 0.16 kPa). The LNFAs with the lignin/PVA ratio of 2.5 and the LNF content of 0.7 g (LNFAs-2.5) possessed the density of 8.88 ± 0.13 mg⋅cm-3, porosity of 99.31 ± 0.01 %, and compressive strength of 4.91 ± 0.16 kPa under a compression strain of 60 %, and it still maintained good composition structures supported even after 150 compression and rebound cycles. The LNFAs-2.5 possessed favorable properties of high-water resistance with contact angle of 150.4° and low thermal conductivity, making synthetic warmth retention materials superior to down feathers.

To achieve dual functionality that can monitor both Al3+ levels in food and the freshness of fish, rice straw fibers (RSFs) were treated in NaOH solutions and then cationized with 2,3-epoxypropyltrimethylammonium chloride, onto which alizarin red S molecules were immobilized through electrostatic interaction to develop a smart felt-like label. An optimized treatment in 5 wt% NaOH solution effectively removed lignin and hemicellulose, facilitating quaternary ammonium group grafting and stable ARS anchoring. The ARS@BRSF-5NaOH exhibited high pH sensitivity, showing visually discernible color changes (ΔE > 5, perceptible to the naked eye) under acidic (pH ≤ 6) and strongly alkaline (pH > 12) conditions. During the storage of the fish, the label transformed from yellow to dark purple (ΔE increase) as TVB-N levels approached 20 mg/100 g, enabling real-time freshness monitoring for protein-rich products. Additionally, the label achieved a detection threshold of 1 × 10−5 mol·L−1 for Al3+ through a coordination-induced chromatic transition (purple to pale pink). This research highlights the feasibility of utilizing an agricultural waste-derived material to develop cost-effective, visually responsive, dual-functional intelligent labels for food safety, offering significant advancements in on-site quality assessment.

The novel incorporation of dragon fruit peel extract (DE), rich in anthocyanins, Zn2+ (from Zinc Alginate) and pectin was applied to create active and intelligent food packaging composite films. These films were characterized for their microstructure and properties. Various levels of anthocyanin extracts (1 %, 3 %, and 5 %) were evaluated for their impact on the films' physical and functional properties, incorporating microstructure, mechanical strength, barrier properties, pH sensitivity, and bacteriostatic effectiveness. The films exhibited a significant antibacterial rate of up to 99.99 % against common foodborne pathogens, enhanced flame retardancy with an enhancement of 32.7 %, and a broad pH sensitivity range, indicating their adaptability to various conditions. The results demonstrated that the prepared indicator film achieved a 50 % reduction in water vapor permeability. Additionally, the mechanical properties were enhanced, with only a slight decrease of 12.2 % in tensile strength and 14.0 % in elongation at break. In tests monitoring shrimp freshness, pectin/ZA/DE films showed notable color changes correlating with shrimp quality. These specific values highlight the pectin/ZA/DE films' potential for real-world applications, suggesting that they have potential applications as smart packaging materials in the food industry.

Biomass aerogels are expected to become thermal insulation materials to overcome the world environment and energy crisis due to their excellent ecological friendliness and thermal insulation performances. In this paper, thermal insulation biomass aerogels were designed based on ionic and physical double cross-linking strategies and directed freezing methods using pectin (P), gelatin (G), and phytic acid (PA) as raw materials. They exhibited remarkable anisotropic structural characteristics, achieving excellent mechanical and thermal insulation performances (thermal conductivities reached 18.95 and 13.40 mW/mK) in different directions. Due to the presence of gelatin and phytic acid, aerogels showed excellent flame retardancy, smoke suppression, and antibacterial performances (antibacterial rates against Staphylococcus aureus and Escherichia coli reached 41.33 and 82.29%, respectively). Furthermore, the coating-modified aerogels showed amazing surface waterproof performance (hydrophobic angle increased to 110 degrees). This study provided a new idea for the preparation of thermal insulation materials with excellent mechanical, flame retardancy, smoke suppression, antibacterial, and surface waterproof performances.