Aerogel Films Research Articles

CNT aerogel film based novel approach for development of ultra-sensitive electrochemical sensor platforms with glassy carbon, screen-printed, and interdigitated electrodes

CNT aerogel film based novel approach for development of ultra-sensitive electrochemical sensor platforms with glassy carbon, screen-printed, and interdigitated electrodes

Making aerogel films like playing LEGO: A universal fabrication strategy for Kevlar based aerogel films with arbitrarily designed functions

Highly flexible, ultrathin and mechanically robust aerogel films activated by functional nanofillers exhibit tremendous potentials for wide applications. However, it is difficult to design different functionalities in a single aerogel film, as different nanofillers often possess opposing properties. Herein, a LEGO®-inspired fabrication strategy to construct Kevlar-based aerogel film with arbitrarily designed functions is introduced by stacking functionalized aerogel film units as stacking LEGO® bricks. The aerogel film units are reliably connected by precursor dispersion-derived LEGO® embossed nodes, leading to superior mechanical strength. Moreover, owing to the flexibility of the LEGO®-inspired assembly method, targeted functions of the aerogel films can be achieved by designing and purposefully combining various stacks. As demonstrations, optimized joule heating, greatly enhanced electromagnetic wave shielding and excellent flame-retardant properties are realized with stacking of different aerogel film units. The unique fabrication strategy opens up opportunities for the design and fabrication of aerogel film with tunable and tailored properties for wide applications.

Impact of High Power Laser Fluence on the Chemical Signatures of Silica Aerogel Films

Impact of High Power Laser Fluence on the Chemical Signatures of Silica Aerogel Films

Lightweight double-layer structured ANF/MXene aerogel film with electromagnetic interference shielding and dynamic infrared camouflage

Lightweight double-layer structured ANF/MXene aerogel film with electromagnetic interference shielding and dynamic infrared camouflage

Polyimide Aerogel Fiber Bundles for Extreme Thermal Management Systems in Aerospace Applications.

Aerogel fibers are an emerging class of ultralightweight materials, which, compared to conventional bulk monolithic and aerogel films, provide better flexibility and extensibility. Despite the recent advancements in this field, due to their highly porous structure, their mechanical properties can be deteriorated. Inspired by the textile industry, we report the development of aerogel fiber bundles with twisted structures as a promising strategy to enhance the mechanical performance and practicality of aerogel fibers. Polyimide (PI) aerogel fibers were prepared via the sol-gel confined transition method. The fibers showed a unique nanostructured assembly with high specific surface area, excellent optical transparency, outstanding flexibility at diverse extreme conditions, self-extinguishing behavior, and superior thermal insulation performance. Using PI aerogel fibers as the backbone, aerogel fiber bundles in various configurations were designed and fabricated. A systematic study was performed to analyze the effect of design parameters on the mechanical performance of the bundles. Results revealed an optimal twist level for bundles, leading to a peak in mechanical properties across various bundle configurations. The observed improvement in mechanical properties was attributed to increased fiber-to-fiber binding strength, enhanced friction, and interlocking mechanism of fibers, underscoring the potential of the optimized twist level for enhancing the performance of aerogel fiber bundles. Overall, the development of aerogel fiber bundles holds great promise in revolutionizing the production of high-performance ultralightweight materials for thermal management applications.

Advanced alginate-based nanofiber aerogels: A synthetic matrix for high-efficiency lysozyme adsorption and controlled release

The development of materials with high lysozyme adsorption is critical for drug delivery and skin wound applications, as it enhances antibacterial properties, stability, and controlled release of therapeutic agents, thereby improving treatment efficacy and safety. Alginate-based nanofiber scaffolds, featuring high surface area and multiple adsorption sites, can efficiently absorb lysozyme and regulate its release through tunable pore channels, offering a promising approach to chronic wound management. In this study, we fabricated poly (vinyl alcohol-co-ethylene) (EVOH) nanofiber-based sodium alginate (ENSA) aerogels using a simple two-step crosslinking procedure. The resulting aerogels, with controllable porosity formed via high-pressure spraying techniques (aerogel film) and molding (aerogel sponge), were evaluated for their high-loading capacity and controllable release of lysozyme. The aerogel film exhibited a remarkable lysozyme adsorption capacity of 1965 ± 36 mg/g, while the aerogel sponge sustained lysozyme release over 14 days. Analysis of the drug-release mechanism through four kinetic models revealed two distinct processes: cation exchange and matrix diffusion. The aerogel's pore structure influenced the diffusion processes, enabling tailored drug release profiles. Additionally, the ENSA aerogels demonstrated good mechanical properties, non-cytotoxicity, and potent antibacterial activity, positioning them as promising materials for skin wound dressings.

Fabrication of Curcumin Grafted Aramid Nanofibers-Based Aerogel Films: Dyes Removal from Contaminated Effluents with High Adsorption Capacity and Antimicrobial Characteristics

Fabrication of Curcumin Grafted Aramid Nanofibers-Based Aerogel Films: Dyes Removal from Contaminated Effluents with High Adsorption Capacity and Antimicrobial Characteristics

Enhancing the electromagnetic interference shielding performance of composite paper with corrugated paper-like structure

The structural design of material significantly influences its electromagnetic interference (EMI) shielding performance, providing an intelligent approach to attain desirable EMI shielding performances. Inspired by the ultra-large distance of the middle layer in corrugated paper, we proposed a novel composite paper with corrugated paper-like structure via the assembling of two pieces of surface-modified filter paper and an aerogel film. Specifically, a conventional filter paper was modified with the conductive hydrogel film consisting of TEMPO-oxidized cellulose nanofibers (TOCNF), cationic starch (CS) and Ti3C2Tx. The TOCNF and CS rapidly formed a composite hydrogel when mixed, due to their electrostatic interactions. The aforementioned aerogel film was produced through the freeze-drying of TOCNF/CS hydrogel, and it enlarged the distance between two conductive hydrogel film modified papers when inserted. The assembled composite papers demonstrated a maximum EMI SE of 71.0 dB, improved by 19.7 % as compared to the control without the aerogel film (59.3 dB). The expansion of the distance between conductive layers likely facilitated the enhancement in the multiple reflections and absorptions of electromagnetic waves. This novel composite paper showed better EMI shielding performance than many previously-reported materials considering the thickness and conductive filler dosage. In addition, the composite paper also showed exceptional infrared stealth capabilities since it effectively shielded the thermal radiation from human body. The composite paper still exhibited good infrared stealth ability at high temperature conditions (up to 120 ℃). Therefore, this research could inspire innovative concepts in designing high-performance and multifunctional EMI shielding materials in an economical way.

Bionic wood-inspired structure enables aerogel film triboelectric material with humidity adaptation

The water molecules adhering to the surface of the triboelectric layer will take away the surface charge when traditional triboelectric nanogenerators (TENGs) operate in the high-humidity environment, resulting in a reduction in triboelectric performance, which significantly constrains the advancement of TENGs. Herein, a green triboelectric material of chitosan/polyvinyl alcohol longitudinal aerogel film (CP-LAF) with excellent humidity adaptation and triboelectric properties (9 cm2, 214 V, 18.25 μA) was prepared by a process of directional freeze-drying assisted mechanical compression with the idea from the anisotropic structure of natural wood. The triboelectric properties of TENGs are enhanced by their layered-ordered porous structure and rough surface. At the same time, it is reusable due to the inherent properties of the components. More importantly, the CP-LAF-based TENG has strong adaptation and stability to a high-humidity environment. Its output voltage at 99 % relative humidity (RH) is 1.6 times that of 50 % RH owing to the triboelectrification involving a large number of water molecules and the increase in the contact area caused by material softening. Additionally, its electrical performance decreases very little after 5000 working cycles. Meantime, it suggests excellent application advantages in energy harvesting and self-powered sensing. This design strategy has the potential to solve the problem of the degradation of traditional triboelectric materials in high-humidity environments. The material provides a stimulating example for the design and preparation of green triboelectric materials that can withstand different humidity environments.

Honeycomb porous regenerated cellulose aerogel films with enhanced thermal dissipation for agricultural mulch application

Agricultural films, essential to contemporary agricultural production, are mostly made from non-biodegradable petroleum-based materials. The use of such films, especially in high-temperature environments, contributes to elevated internal temperatures in direct sunlight, adversely affecting crop appearance and quality. In this work, rice straw was used as the raw material to prepare biodegradable chemically crosslinked regenerated cellulose aerogel films (RCAF-CC) by combining physical dissolution regeneration, chemical cross-linking, and freeze-drying. The resulting RCAF-CC is notable for its high middle-infrared emissivity and high solar reflectivity, which significantly aid in thermal dissipation for agricultural mulch by enhancing infrared radiation and solar reflection. Compared to traditional polyethylene films, RCAF-CC, with its superior radiative cooling properties and lower water vapor transport rate, has a significant advantage in the growth trend and survival rate of cherry radishes. It is worth noting that the RCAF-CC achieved the degradation rate of 74.4 % in the 100-day soil burial experiment, and the soybean seeds grown in the degraded soil grew well, showing excellent eco-friendliness. These results show that RCAF-CC can be an alternative source of traditional agricultural films, solving the problems of non-biodegradable and high internal temperatures of the films under direct sunlight.

Mechanically robust and thermal-insulated polyimide aerogel films by polymerization-regulated strategy for flexible thermal protection

The development of flexible and foldable aerogels for thermal protection in harsh environments has been a long-term challenge as high porosity and weak interface connection can result in typical brittleness. Herein, a remarkable polymerization-regulated strategy was proposed to prepare polyimide (PI) aerogel films with high flexibility and efficient thermal insulation in extreme temperatures by using a facile phase-separation (PS-PI films) method. The polymerization degree of monomers was innovatively used to regulate the flexibility and mechanical properties of PS-PI films by slightly regulating the proportion of monomers. The results showed that the PI aerogel film realized the transition from brittleness to high flexibility, and the tensile strength and fracture strain of PS-PI films were increased by 3 times (11.7 MPa) and 4 times (18.7 %), respectively. Besides, a finite element model was established to analyze the tensile deformation process, revealing the destruction mechanism of aerogel film. The prepared PS-PI film also exhibited robust mechanical properties and efficient thermal insulation properties at extreme temperatures (−130 to 300 °C). The developed PS-PI film possessed high flexibility and efficient thermal-insulated performance at extreme temperatures, which could be a potential candidate for thermal protection in aerospace, energy, and buildings.

Two birds with one stone: Co/Fe bi-MOFs@PAN nanofiber aerogel films for efficient degradation of organic contaminants and separation of emulsions

The development of materials for effective treatment of complex water is in high demand, but remains challenging. In this study, a multifunctional Co/Fe bi-MOFs decorated polyacrylonitrile nanofiber aerogel film was rationally designed and fabricated using a combination of electrospinning, freeze-drying, and subsequent in-situ hydrothermal methods. The NAF has a hierarchically porous architecture and is capable of degrading dyes and separating oil-in-water emulsions. The results demonstrate that the NAF has outstanding catalytic performance in peroxymonosulfate activation for methylene blue degradation, with a degradation efficiency of above 99.74 % and a reaction rate of 0.0911 min−1 within 40 min. Electron paramagnetic resonance analysis and quenching tests revealed that sulfate radical, hydroxyl radical, singlet oxygen, and superoxide radical are all involved in the degradation of MB and sulfate radical is the major reactive species. Furthermore, the composite NAF can separate oil-in-water emulsions with superior efficiency of above 99.85 % and desirable flux higher than 422 L·m−2·h−1, due to its hierarchically porous architecture and remarkable wettability. The composite NAF displays robust reusability and stability for long-term use. This study demonstrates the benefits of integrating advanced oxidation processes with membrane technology and provides novel perspectives into the evolution of multifunctional materials for complex wastewater treatment.

Fabrication and Advanced Imaging Characterization of Magnetic Aerogel-Based Thin Films for Water Decontamination.

Aerogels have emerged as appealing materials for various applications due to their unique features, such as low density, high porosity, high surface area, and low thermal conductivity. Aiming to bring the advantages of these materials to the environmental field, this study focuses on synthesizing magnetic silica aerogel-based films suitable for water decontamination. In this respect, a novel microfluidic platform was created to obtain core-shell iron oxide nanoparticles that were further incorporated into gel-forming precursor solutions. Afterward, dip-coating deposition was utilized to create thin layers of silica-based gels, which were further processed by 15-hour gelation time, solvent transfer, and further CO2 desiccation. A series of physicochemical analyses (XRD, HR-MS FT-ICR, FT-IR, TEM, SEM, and EDS) were performed to characterize the final films and intermediate products. The proposed advanced imaging experimental model for film homogeneity and adsorption characteristics confirmed uniform aerogel film deposition, nanostructured surface, and ability to remove pesticides from contaminated water samples. Based on thorough investigations, it was concluded that the fabricated magnetic aerogel-based thin films are promising candidates for water decontamination and novel solid-phase extraction sample preparation.

Chitosan aerogel loaded with biogenic palladium nanoparticles CH/Pd NPs exert antibacterial activity and wound addressing application in vitro and in vivo against bacterial skin infections

Bacterial skin infections that infect wounds and burns are considered one of the most serious medical problems that lead to delay wound healing, toxicity and even death. Therefore, there is an urgent need to develop an effective pharmaceutical material that promotes the treating of skin bacterial infections. Within this, we aimed in this study to synthesis and assess the effectiveness of novel chitosan/palladium nanoparticles (CH/Pd NPs) aerogel composites in treating bacterial skin infections and wound healing. Green method was employed for synthesis of Pd NPs using Allium sativum (A. sativum) extract, while crosslinking process and freeze-drying cycle were utilized for preparation of CH/Pd NPs aerogel composites. The prepared Pd NPs and CH/Pd NPs aerogel composite were thoroughly characterized using UV–vis, FTIR, XRD and SEM. The GC–MS analysis revealed that the main components in the A. sativum were diallyl disulfide (55.88 %) and diallyl trisulfide (24.34 %) which were among the four identified components. Additionally, the total phenols and flavonoids contents were 61.3 mg GAE/100 g and 18.8 mg QE/100 g, respectively. The swelling capacity of CH/Pd NPs aerogel microspheres reach 400 % with blood compatibility and slightly hemolysis ratio about 0.4 %. In vitro, the antibacterial studies demonstrated that loading Pd NPs with CH aerogel microspheres enhanced their effectiveness against MDR bacteria with complete inhibition for all bacterial strains growth. The CH/Pd NPs aerogel microspheres exhibited a significant inhibitory effect on biofilm formation. The biofilm inhibition percentage was found to be 87 % against the biofilm of S. aureus and 80 % against the biofilm of P. aeruginosa. In vivo infection model in rats, CH and CH/Pd NPs aerogel films stimulated skin tissue formation and healing wounds completely in 6 days with highly reduced in MDR and biofilm producing bacterial count. Finally, CH/Pd NPs aerogel composites represent a promising therapeutic strategy for the effective and enhanced healing of infected wounds.

Distributed activation energy treatment of polyimide aerogel and its blocking effect on thermal runaway propagation of ternary battery

The thermal runaway of lithium batteries has become an urgent problem that needs to be solved today. In this study, polyimide aerogel materials with high temperature resistance and low thermal conductivity were prepared by supercritical drying equipment. Firstly, the activation energy distribution of the two pseudo-components of polyimide aerogels was calculated by TGA data at different heating rates, and then the optimal kinetic parameters were obtained. Secondly, a series of experiments were designed to study the blocking effect of polyimide aerogel films with different thicknesses (0.5 mm, 1 mm, 1.5 mm, and 2 mm) on the uncontrolled transmission of batteries, which showed that 2 mm film could successfully block the uncontrolled transmission of battery heat at 711.9 °C. 0.5 mm, 1 mm and 1.5 mm polyimide aerogel films can delay the thermal runaway of the battery, and the delay time was 182 s, 224 s and 259 s respectively. At the same time, the indicator gas was detected and analyzed, indicating that the barrier material can effectively reduce the content of CO2 gas and heat release rate. This study provides new enlightenment for the development of polyimide aerogels, and new ideas for the thermal insulation design of batteries.

Bio-based and fireproof radiative cooling aerogel film: Achieving higher sustainability and safety

Even though significant advantages in the energy-free regulation of temperature are presented, the practical applications of radiative cooling materials in buildings and human surfaces still involve many safety issues, especially for fire hazards of polymer-based materials. Meanwhile, renewable and environmentally friendly materials are urgently needed to develop suitable radiative cooling materials with no adverse environmental impact. Herein, a chitosan-derived composite aerogel film with high solar reflection provided by the addition of melamine-phytic acid (MA/PA) hybrids is designed and prepared, presenting radiative cooling and fireproof performances. The instinct deep-yellow color of chitosan (CS) is successfully shielded by high-reflective MA/PA hybrids, while IR emissivity of up to 90.4 % and solar reflectivity of ∼ 89.3 % are achieved. In outdoor environments, this composite aerogel shows sub-ambient temperature drops of ∼ 4.3 °C and ∼ 3.1 °C in cloudless and cloudy weather, presenting a robust cooling effect. In addition, CS-MA/PA composite aerogel film with 3 mm thickness can isolate the fire of ∼ 500 °C, showing superior fire safety attributed to the synergistic flame retardant effects among chitosan, phytic acid, and melamine, which suppress the initial growth of fire and promote the rapid formation of protective char layer. This work provides a bio-based, fire-safe, and radiative cooling material to decrease the energy consumption of temperature regulation with a more environmentally friendly and safer approach, further promoting the practical application of radiative cooling materials.

Visible Microfluidic Deprotonation for Aramid Nanofibers as Building Blocks of Cascade-Microfluidic-Processed Colloidal Aerogels.

Microfluidic deprotonation approach is proposed to realize continuous, scalable, efficient, and uniform production of aramid nanofibers (ANFs)by virtue of large specific surface area, high mixing efficiency, strong heat transfer capacity, narrow residence time distribution, mild laminar-flow process, and amplification-free effect of the microchannel reactor. By means of monitoring capabilities endowed by the high transparency of the microchannel, the kinetic exfoliation process of original aramid particles is in situ observed and the corresponding exfoliation mechanism is established quantificationally. The deprotonated time can be reduced from the traditional several days to 7 min for the final colloidal dispersion due to the synergistic effect between enhanced local shearing/mixing and the rotational motion of aramid particles in microchannel revealed by numerical simulations. Furthermore, the cascade microfluidic processing approach is used to make various ANF colloidal aerogels including aerogel fibers, aerogel films, and 3D-printed aerogel articles. Comprehensive characterizations show that these cascade-microfluidic-processed colloidal aerogels have identical features as those prepared in batch-style mode, revealing the versatile use value of these ANFs. This work achieves significant progress toward continuous and efficient production of ANFs, bringing about appreciable prospects for the practical application of ANF-based materials and providing inspiration for exfoliating any other nano-building blocks.

Competitively Assembled Aramid‐MXene Janus Aerogel Film Exhibiting Concurrently Robust Shielding and Effective Anti‐Reflection Performance

AbstractThe fast progress in electronic devices demands superior anti‐reflective performance of electromagnetic interference shielding materials. However, high‐performance shielding strategies are mainly dependent on reflection effects and this inevitably results in a trade‐off between shielding and anti‐reflective properties during structural designs. Herein, this work proposes a novel gradual heterogeneity design to fundamentally overcome the contradiction. The different steric hindrances in MXene nanosheets and aramid nanoclusters endow the competitively assembled laminal aerogel films with a unique Janus architecture. This Janus structure presents continuous gradient asymmetries and abundant cavities that enable prolonged energy attenuation paths and minimized reflection. Comparing to isotropic counterparts, the gradient design performances a 2174% reduction in reflection coefficient (0.0039) and a 53% increase in shielding efficiency (60.49 dB) in the terahertz band, both of which significantly outperform most state‐of‐the‐art anti‐reflective shielding structures. Moreover, the Janus architecture comprising interconnected arch‐shaped substructures provides the aerogel films with anisotropic EMI and thermal management capabilities, coupled with robust structural and performance stability. This work provides a conceptually novel platform for developing asymmetric architecture for advanced shielding materials.

Highly Porous Yet Transparent Mechanically Flexible Aerogels Realizing Solar-Thermal Regulatory Cooling

HighlightsA lamellar-structured fluorinated cellulose nanofiber aerogel film is prepared by filtration-induced delaminated gelation and ambient drying.The aerogel film demonstrates exceptional mechanical flexibility and resistance to complex deformations.The aerogel film displays low thermal conductivity, high visible-light transmittance and superior selective infrared emissivity, rendering it high solar-thermal regulatory cooling performance.

Highly Stretchable Semiconducting Aerogel Films for High‐Performance Flexible Electronics

AbstractHighly stretchable aerogel films are attractive for advanced next‐generation stretchable electronics. However, it is a great challenge to achieve high stretchability for aerogel films. Here, several types of unprecedented ultra‐stretchable semiconducting polymer‐based aerogel films with crimpled porous structures are developed via crosslinking and template methods combined with uniaxial and biaxial pre‐stretching strategies. The semiconducting aerogel films obtained by uniaxial pre‐stretching exhibit ultrahigh stretchability up to 100–200%, while those obtained by biaxial pre‐stretching show high biaxial stretchability up to 50%. The resulting aerogel films show strain‐insensitive electrical and joule heating properties. A prototype of the aerogel film‐based stretchable organic electrochemical transistor (OECT) is developed for the first time. Benefiting from their unique porous structures, the aerogel film‐based OECTs exhibit enhanced on/off ratio and transconductance compared with corresponding dense film‐based OECTs, high stretchability up to 100%, and high stretching stability with 10 000 stretching cycles under 30% strain. It is demonstrated that the aerogel film‐based OECTs can be applied as high‐performance stretchable artificial synapses and biosensors. This work gives a versatile strategy toward highly stretchable aerogel films promising for flexible electronics.