Polymers
·
2022
·Vol. 14
·期 6
·1077
·
IF 4.967
Peiyuan Feng,Xiwen Wang,Jin Yang
Aerogels have great potential in oil absorption applications; however, many reported aerogels have the drawbacks of a low oil-recovery rate and poor mechanical properties, which limit their application. In this study, highly reusable graphene oxide (GO)/TEMPO-oxidized cellulose nanofiber (TOCN)/polyvinyl alcohol (PVA) aerogels with excellent mechanical properties and with an architecture similar to that ofThalia dealbatastems were fabricated through a three-step process of bidirectional-freezing, freeze-drying, and chemical vapor deposition (CVD) modification. After CVD modification, the modified GTPA (MGTPA) accorded hydrophobicity. The synergistic effects of the three components and the unique biomimetic structure conferred biomimetic-MGTPA (b-MGTPA) with excellent compressible properties. As an adsorbent, b-MGTPA showed a high adsorption capacity (75–151 g/g) for various types of organic solvents. In addition, its high compressibility enables b-MGTPA to have fast and highly efficient recovery of absorbed oil through simple mechanical squeezing and it possesses excellent reusable stability (the oil recovery rate and oil retention rate reached 80% and 91.5%, respectively, after 10 repeated absorption–compression cycles).Keywords:aerogel;bidirectional freezing;biomimetic structure;oil absorption;recyclability
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHINESE JOURNAL OF POLYMER SCIENCE
·
2018
·Vol. 36
·期 7
·880-887
·
IF 2.016
Chen Sen-He,Wu Bai-Heng,Fu Jin-Cheng,Wang Guo-Jun,Wan Ling-Shu,Xu Zhi-Kang
Polystyrene membranes with precisely controlled and vertically oriented pores are fabricated by a bidirectional freezing process. In this process, the influence of polymer in growth of diphenyl sulfone (DPS) crystals has been demonstrated by XRD and simulated by DFT based on the interaction between DPS crystal faces and polystyrene (PS). The influence of temperature gradient on membrane structures is also elucidated. Compared to the original membrane and modified traditional membranes, modified PS membranes with vertically oriented pores show large and stable fluxes in the processes of multiple oil and water separation.
研究领域:
材料科学
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环境工程
✓ 已验证
产品关联
DOI
高影响因子
Bioinspiration & Biomimetics
·
2021
·Vol. 17
·期 1
·015002
·
IF 2.956
Nifang Zhao,Anran Mao,Ziyu Shao,Hao Bai
Porous ceramic materials are attractive candidates for thermal insulation. However, effective ways to develop porous ceramics with high mechanical and thermal insulation performances are still lacking. Herein, an anisotropic porous silica ceramic with hierarchical architecture, i.e. long-range aligned lamellar layers composed of hollow silica spheres, was fabricated applying a facile bidirectional freezing method. Due to such anisotropic structure, the as-prepared porous silica ceramic displays low thermal conductivity across the layers and high compressive strength along the layers. Additionally, the anisotropic porous silica ceramic is fire-resistant. As a proof of concept, a mini-house was roofed with the anisotropic porous silica ceramic, showing that the indoor temperature could be stabilized against environmental temperature change, making this porous ceramic a promising candidate for energy efficient buildings and other industrial applications. Our study highlights the possibility of combining intrinsically exclusive properties in engineering materials through constructing biomimetic porous structures.
研究领域:
材料科学
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热能工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2022
·Vol. 57
·期 27
·13097-13108
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IF 4.682
Feng Peiyuan,Wang Xiwen,Yang Jin
Cellulose-based aerogels have become a great potential for oil absorption applications due to their wide range of sources, low density, and good adsorption properties. However, many reported cellulose-based aerogels to have the drawbacks of low oil recovery rate and poor mechanical, which limit their application. In this study, high reusable and excellent mechanical properties silylated TEMPO-oxidized nanofibers/polyvinyl alcohol aerogels (STPA) were fabricated through a three-step process of aqueous silylation, bidirectional freezing, and freeze-drying. A bidirectional freezing technique was employed to obtain two unique structural aerogels by adjusting the methyltrimethoxysilane concentration. The STPA possessed many excellent physical properties, such as ultralight (9.79 mg/cm3), hydrophobicity (136°), and compressibility; as an adsorbent, STPA showed high adsorption capacity (51–111 g/g) for various types of organic solvents. Furthermore, the excellent compressibility enables STPA fast and highly efficient recovery of the absorbed oil by simple mechanical squeeze. It possesses an excellent oil recovery rate of 80% and maintains around 90% of its initial saturated absorption capacity after 50 cycles of absorption–squeezing. Therefore, the successful microstructure design of the biomass-aerogel through bidirectional freezing could provide new thoughts for the design of multifunctional oil absorbents and STPA with good mechanical properties and reusability showing promising prospects in the field of water treatment. Graphical abstract
研究领域:
材料科学
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环境科学
✓ 已验证
DOI
高影响因子
ACS Nano
·
2017
·
IF 13.942
Miao Yang,Nifang Zhao,Ying Cui,Weiwei Gao,Qian Zhao,Chao Gao,Hao Bai,Tao Xie
Materials combining lightweight, robust mechanical performances, and multifunctionality are highly desirable for engineering applications. Graphene aerogels have emerged as attractive candidates. Despite recent progresses, the bottleneck remains how to simultaneously achieve both strength and resilience. While multiscale architecture designs may offer a possible route, the difficulty lies in the lack of design guidelines and how to experimentally achieve the necessary structure control over multiple length scales. The latter is even more challenging when manufacturing scalability is taken into account. The Thalia dealbata stem is a naturally porous material that is lightweight, strong, and resilient, owing to its architecture with three-dimensional (3D) interconnected lamellar layers. Inspired by such, we assemble graphene oxide (GO) sheets into a similar architecture using a bidirectional freezing technique. Subsequent freeze-drying and thermal reduction results in graphene aerogels with highly tunable 3D architectures, consequently an unusual combination of strength and resilience. With their additional electrical conductivity, these graphene aerogels are potentially useful for mechanically switchable electronics. Beyond such, our study establishes bidirectional freezing as a general method to achieve multiscale architectural control in a scalable manner that can be extended to many other material systems.
研究领域:
材料科学
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纳米科技
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生物医学工程
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先进制造
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功能材料
✓ 已验证
DOI
高影响因子
APL Materials
·
2024
·Vol. 12
·期 5
·
IF 5.3
Wang Guanyu,Yang Yadong,Cao Wenzhe,Wan Caichao
Strain sensors based on porous conductive polymers (CPCs) have garnered growing research interest for their potential applications in motion detection, healthcare, human–computer interaction, and artificial intelligence. However, the complexity of CPC processing makes it difficult to achieve the controlled design of microscopic porous structures, leading to simple and random porous structures, thus limiting their further use in the field of pressure sensing. This paper presents a strain sensor with a high-performance, wood-like structure composed of flexible conductive carbon black/plastic polyurethane foam (BWCT) using a bidirectional freeze casting process. The results show that, compared with conventional random freezing and unidirectional freezing, the bidirectional freeze casting process can effectively realize multiscale control of the composite structure, which results in a good laminar porous structure of the prepared BWCT. This parallel laminar structure not only contributes to the layered transfer of stresses but also avoids the local concentration of stresses. At the same time, it significantly increases the directional electrical conduction ability, which results in high sensing stability performance. In particular, the BWCT sensors had a wide detection range (80%), a lower limit of detection (0.2%), rapid response and relaxation times (200 ms), as well as exceptional durability (>2000 cycles). Furthermore, the BWCT was integrated into a wearable sensor to monitor various human motions, including arm bending, squatting, and walking, demonstrating reliable detection performance. Altogether, the BWCT sensors are promising in expanding the application but also offer guidance for designing high-performance wearable strain sensors.
研究领域:
材料科学
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传感器技术
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柔性电子
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产品关联
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2019
·Vol. 29
·期 13
·1900412
·
IF 15.621
Jingkai Han,Gaolai Du,Weiwei Gao,Hao Bai
Polymer-based thermal interface materials (TIMs) with excellent thermal conductivity and electrical resistivity are in high demand in the electronics industry. In the past decade, thermally conductive fillers, such as boron nitride nanosheets (BNNS), were usually incorporated into the polymer-based TIMs to improve their thermal conductivity for efficient heat management. However, the thermal performance of those composites means that they are still far from practical applications, mainly because of poor control over the 3D conductive network. In the present work, a high thermally conductive BNNS/epoxy composite is fabricated by building a nacre-mimetic 3D conductive network within an epoxy resin matrix, realized by a unique bidirectional freezing technique. The as-prepared composite exhibits a high thermal conductivity (6.07 W m −1 K −1 ) at 15 vol% BNNS loading, outstanding electrical resistivity, and thermal stability, making it attractive to electronic packaging applications. In addition, this research provides a promising strategy to achieve high thermal conductive polymer-based TIMs by building efficient 3D conductive networks.
研究领域:
材料科学
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热管理技术
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电子封装材料
✓ 已验证
产品关联
DOI
高影响因子
ACS Nano
·
2017
·
IF 13.942
Nifang Zhao,Miao Yang,Qian Zhao,Weiwei Gao,Tao Xie,Hao Bai
Through designing hierarchical structures, particularly optimizing the chemical and architectural interactions at its inorganic/organic interface, nacre has achieved an excellent combination of contradictory mechanical properties such as strength and toughness, which is highly demanded yet difficult to achieve by most synthetic materials. Most techniques applied to develop nacre-mimetic composites have been focused on mimicking the “brick-and-mortar” structure, but the interfacial architectural features, especially the asperities and mineral bridges of “bricks”, have been rarely concerned, which are of equal importance for enhancing mechanical properties of nacre. Here, we used a modified bidirectional freezing method followed by uniaxial pressing and chemical reduction to assemble a nacre-mimetic graphene/poly(vinyl alcohol) composite film, with both asperities and bridges introduced in addition to the lamellar layers to mimic the interfacial architectural interactions found in nacre. As such, we have developed a composite film that is not only strong (up to ∼150.9 MPa), but also tough (up to ∼8.50 MJ/m3), and highly stretchable (up to ∼10.44%), difficult to obtain by other methods. This was all achieved by only interfacial architectural engineering within the traditional “brick-and-mortar” structure, without introducing a third component or employing chemical cross-linker as in some other nacre-mimetic systems. More importantly, we believe that the design principles and processing strategies reported here can also be applied to other material systems to develop strong and stretchable materials.
研究领域:
材料科学
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纳米复合材料
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生物仿生学
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高分子材料
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力学性能
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry A
·
2024
·
IF 10.7
Ruolin Han,Jiafei Ren,Hui Quan,Xuehe Wang,Wenning Qi,Dali Gao,Zheng Zhou,Qifang Li,Guang-Xin Chen
According to theoretical studies on ceramic/polymer composite dielectrics, the maximum achievable dielectric constant is observed in composites with a parallel structure connecting the ceramic and polymer phases. However, the practical preparation of parallel-structured composites poses significant challenges. Here, aimed at the theoretical model, we prepared a parallel-structured BaTiO3 (BT) skeleton through bidirectional freezing, and further prepared a parallel-structured BaTiO3/epoxy (BT/EP) composite through vacuum impregnation. When the electric field is completely parallel to the interfaces between BT and EP phases, the composites basically realize the ideal parallel structure and exhibit excellent dielectric properties. For example, the composite with 59 vol% BT content has an ultra-high dielectric constant of 2017 and shows a low loss of <0.02 at 1 kHz. Even at a low BT content of 18 vol%, the dielectric constant of the parallel-structured composite is still as high as 489 at 1 kHz. Based on the ultra-high dielectric constant of the parallel-structured composites, a high polarization intensity of 24.8 μC cm−2 and a discharge energy density of 13.4 × 10−2 J cm−3 are achieved at a low electric field of 4 kV mm−1. Experiments and simulations demonstrated that the parallel arrangement along the direction of the electric field and the connectivity of the ceramic fillers are the key factors to realize the parallel structure. This work achieved the parallel structure described by the theoretical model and further clarified the relationship between the structure and dielectric properties of the composites.
研究领域:
材料科学
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电气工程
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复合材料
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2023
·
IF 9.5
Ruolin Han,Jiafei Ren,Zheng Zhou,Guang-Xin Chen,Qifang Li
Typically, the basic method to enhance the dielectric response of polymer-based composites is to fill giant dielectric ceramic fillers, such as BaTiO3 and CaCu3Ti4O12, into the polymer matrix. Here, by using low-k boron nitride (BN) with well-controlled microstructure and surface, we successfully prepared a high-k polymeric composite, where the improvement in the dielectric constant of the composite even exceeds that of composites containing BaTiO3 and CaCu3Ti4O12 particles at the same weight percent. First, a lamellar boron nitride nanosheet (BNNS) aerogel was prepared by bidirectional freezing and freeze drying, respectively, and then the aerogel was calcined at 1000 °C to obtain the lamellar BNNS skeleton with some hydroxyl groups. Finally, the epoxy resin (EP) was vacuum impregnated into the BNNS skeleton and cured inside to prepare the lamellar-structured BNNSs/EP (LBE) composites. Interestingly, the dielectric constants of LBE with a 10 wt % BNNS content reached 8.5 at 103 Hz, which was higher by 2.7 times than that of pure EP. The experimental data and the finite element simulations suggested that the increased dielectric constants of LBE resulted from the combination of two factors, namely, the lamellar microstructure and the hydroxyl groups. The stacking of the BNNS phase into a highly connected lamellar skeleton significantly increased the internal electric field and the polarization intensity, while the introduction of hydroxyl groups on the BNNS surface further improved the polarization of the composite, resulting in a significant increase in the dielectric constant of the LBE. This work provides a new strategy for improving the dielectric constant through the microstructure design of composites.
研究领域:
材料科学
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复合材料
·
介电材料
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聚合物科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Tongyuan Meng,Zeen Wang,Gui Wang,Bo Li,Ying Xu,Haiying Zhao,Xinhui Gao,Zhaoxin Zhong,Zhanhong Chen,Yang Wang,Yushi Qi,Futian Liu
Bidirectional freeze casting combined with pressure infiltration has demonstrated significant potential as an effective approach for fabricating bioinspired lamellar composites with excellent strength and toughness. However, their dynamic mechanical response remains underexplored. In this study, B 4 C/2024Al composites with long-range ordered nacre-like architectures were fabricated using bidirectional freeze casting followed by pressure infiltration. The mechanical properties and deformation behavior under both quasi-static and dynamic compression conditions were systematically investigated. The results reveal that dynamic compressive strength and strain were significantly higher than their quasi-static counterparts, largely attributed to strain rate hardening and localized matrix melting. Compared to unidirectionally structured composites, the bidirectionally structured ones exhibited superior mechanical performance, achieving a maximum compressive strength of 1088.6 MPa at a strain rate of 3000 s −1 (40 vol% B 4 C/2024Al composite). A clear dependence of flow stress and energy absorption capability on B 4 C volume fraction was observed. As B 4 C content increased, the compressive strength rose, but dynamic strain energy density showed a decreasing trend beyond 20 vol% due to reduced ductility. Specifically, the energy density peaked at 133.08 MJ/m 3 for the 20 vol% composite and declined with further ceramic addition, indicating a trade-off between strength and impact energy absorption. The enhanced toughness under dynamic loading is primarily attributed to adiabatic shear localization in the aluminum matrix, which facilitates localized softening and strain accommodation. Additional contributions include crack deflection and branching within the hard ceramic layers, as well as plastic deformation and thermal softening-induced toughening mechanisms in the metallic phase. These findings highlight the promise of nacre-inspired B 4 C/Al composites for advanced lightweight armor systems, offering an optimized balance between strength, toughness, and energy absorption under high-strain-rate loading.
研究领域:
材料科学
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机械工程
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复合材料
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仿生材料
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动态力学行为
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2022
·
IF 7.968
Yan Sun,Wenjie Ye,Jianfeng Xi,Youlu Chu,Huining Xiao,Weibing Wu
Elastic superhydrophobic aerogels have attracted significant attention to treat increasingly serious oil pollution because of their recycling performance. Using chitosan (CS) and cellulose nanofibrillated fiber (CNF) as raw materials, ultralight and elastic aerogels with the highly-oriented wavy structures were prepared by bidirectional freezing, chemical crosslinking, and chemical vapor deposition (CVD) for oil-water separation. Both the chemical crosslinking and CVD made the aerogels possess good mechanical strength at low density. The aerogel exhibited excellent shape recovery, maintaining more than 88% of its original compressive strength after 50 cycles of compression-release testing, with a high recovery rate of 96.6%. The shape memory property of the bio-based aerogels was improved with a decrease in density. The adsorption capacities of various organic solvents are more than 100 g/g, especially that of chloroform up to 232 g/g. After 10 simple and convenient adsorption-extrusion cycles, the adsorption retention rate of the aerogel can still reach 87.5%. This type of bio-based aerogel with excellent recycling performance has broad application prospects in the field of oil-water separation.
研究领域:
材料科学
·
环境工程
·
化学工程
·
生物技术
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）