JOURNAL OF MEMBRANE SCIENCE
·
2024
·
IF 8.4
Zhiguang Zhang,Xiaolong Ren,Guolong Huo,Xiaowei Zhou,Hao Chen,Hongjun Zhang,Shuanyan Kang,Xiuling Chen,Nanwen Li
6FDA-based polyimide air-dehumidification membrane has been considered as one of the most advanced technologies for the energy-saving heating, ventilation, and air-conditioning systems due to their excellent solubility and processing. Nevertheless, there are few reports about the effect of free volume and hydrophilic groups on dehumidification performance. Herein, we propose to tune the free volume and hydrophilicity of 6FDA-based polyimides by tuning the hydrophilicity/hydrophobicity of diamines and/or introducing of hydrophilic carboxylic acid groups, and thus to develop a system that would support high H 2 O/N 2 separation performance for dehumidification and retain excellent mechanical properties. It is found that 6FDA/mPDA membrane shows much higher H 2 O/N 2 separation performance (i.e., H 2 O permeability 12480 Barrer and H 2 O/N 2 separation factor of 13867) than that of the 6FDA/TFDB and 6FDA/DAM membranes even though its lower FFV. It is suggested that the FFV had a negligible effect on the H 2 O/N 2 separation performance. Although the introduction of highly hydrophilic –COOH groups could significantly increase the H 2 O/N 2 separation performance of hydrophobic 6FDA/TFMB and 6FDA/DAM membranes, the performance is still lower than that of 6FDA/mPDA membrane with similar hydrophilicity. In addition, we found that more –COOH groups to polymers can lead to the possible formation of hydrophilic/hydrophobic separation in membrane which will result in the rapid water vapor condensation and thus unstable air-dehumidification. Thus, the excessive hydrophilicity of 6FDA/mPDA-DABA showed a decreased H 2 O/N 2 separation performance compared with 6FDA/mPDA membrane. These results indicated that the excellent H 2 O/N 2 separation performance mainly depends on reasonable hydrophilicity of polyimide membrane without excessive hydrophilic groups and high FFV.
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JOURNAL OF MATERIALS CHEMISTRY
·
2011
·Vol. 22
·期 2
·520-526
·
IF 5.101
Benlin Hu,Fei Zhuge,Xiaojian Zhu,Shanshan Peng,Xinxin Chen,Liang Pan,Qing Yan,Run-Wei Li
A new polyimide bearing the functional pendant 9-phenyl-9H-carbazole moieties, poly[2,2-(4,4′-di(N-benzyloxycarbazole)-3,3′-biphenylene)propane-hexafluoroisopropylidenediphthalimide] (6F-BAHP-PC PI), has been designed as a functional material for resistance memory devices. The ITO/6F-BAHP-PC PI/Ag memory device exhibits nonvolatile resistive switching (RS) with a high ON/OFF ratio (>106), long retention time (>6 × 104 s), good endurance, and low power consumption (∼100 μW). In situconductive atomic force microscopy measurements show that the RS of 6F-BAHP-PC PI originates from the formation/rupture of nanoscale conducting filaments.
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PROGRESS IN ORGANIC COATINGS
·
2025
·
IF 7.3
Zhongli Zhang,Zhensheng Wu,Shuai Zheng,Haitao Yang,Fuqiang Tian
Polyimide inorganic nanocomposites have become a major focus of research in various fields due to their excellent integrated properties. This study adopts a combination of theoretical simulations and experimental methods. Using Density Functional Theory (DFT) calculations, the microscopic properties of polyimide molecules and nano-TiO 2 and nano-Al 2 O 3 were investigated, while Molecular Dynamics (MD) simulations revealed the microscopic mechanism behind the thermal breakdown of polyimide films. Subsequently, polyimide/titanium dioxide (PI/nano-TiO 2 ) and polyimide/titanium dioxide/alumina (PI/nano-TiO 2 /nano-Al 2 O 3 ) nanocomposite films were prepared. The results showed that the breakdown strength of the PI/nano-TiO 2 film was 3.58 times that of conventional polyimide films. The surface modification of nanoparticles was achieved by adding the coupling agent KH550, which enhanced the structure, morphology, and overall properties of the composite films, significantly improving their thermal stability. Our research framework adopts a multi-scale approach, starting with insights at the microscopic level obtained from Density Functional Theory (DFT) calculations and MD simulations, followed by experimental validation, and ultimately classifying the breakdown strength through machine learning. We systematically analyzed the breakdown performance of polyimide films across multiple scales, from molecular simulations and experimental analysis to machine learning, providing theoretical support and practical reference for the design of nanocomposite films, and demonstrating the potential of this material for high-performance dielectric applications.
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JOURNAL OF APPLIED POLYMER SCIENCE
·
2025
·
IF 2.8
Shihao Fu,Chang Sun,Lixin Han,Zhiqiang Li,Shuai Guo,Guangbin Li,Zhu Long
High-performance thermal insulation is critically needed in applications where heat transfer must be substantially minimized. Traditional insulating materials, whether organic or inorganic, often suffer from thermal instability or mechanical fragility. Herein, we introduce a series of lightweight, highly porous polyimide/aluminum oxide cluster (PI/AlOC) composite aerogels that exhibit superior thermal insulation properties, achieved through freeze-drying and thermal imidization processes. The aluminum oxide clusters serve as cross-linking agents, enhancing the interaction between polyimide molecular chains and endowing the composite with improved structural integrity and mechanical robustness, as evidenced by a compression modulus of 8.7 MPa, six-fold greater than that of pure PI aerogels. Moreover, the high porosity, reduced pore size, and three-dimensional network structure of the PI/AlOC composite aerogel confer exceptional thermal insulation performance, particularly at elevated temperatures, surpassing that of commercial thermal insulation materials. Thus, the PI/AlOC composite aerogels, with their high mechanical strength and outstanding thermal insulation, are promising for practical applications in thermal insulation.
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Materials
·
2024
·Vol. 17
·期 16
·4135
·
IF 3.1
Zijia Wang,Yawen Chang,Siyang Jia,Fujuan Liu
In this study, polyimide (PI) and polysulfonamide (PSA) were used as base materials, and polyethylene glycol (PEG) was added to successfully prepare PI/PSA/PEG nanofiber membranes through electrospinning technology. Subsequently, water etching was performed on the membranes, utilizing the water solubility of PEG to form the rough wrinkled structure, further enhancing the surface hydrophobicity. The experimental results showed that under the conditions of a spinning voltage of 10 kV, PI/PSA mass fraction of 15 wt.%, and PEG-to-PI/PSA mass ratio of 1/3, the obtained fiber membranes exhibit a uniform morphology (an average diameter of 0.73 µm) and excellent hydrophobicity (the initial water contact angle (WCA) reaching 130.4°). After PEG water etching, the surface of the PI/PSA/PEG hydrophobic membranes formed the rough wrinkled structure, which not only improved their mechanical properties but also further enhanced their hydrophobicity (the initial WCA increasing to 137.9°). Hence, fiber membranes are expected to have broad application prospects in fields such as waterproofing and moisture permeability.
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PubMed
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2024
·
IF 5.8
Lujie Dong,Ping Zhang,Chao Xiao,Xingyou Tian,HuiChao Du,Xian Zhang,Hui Zhang
Electromagnetic interference (EMI) shielding films were widely utilized in various electronic devices, but they were prone to damage and performance degradation in harsh environments. Therefore, it was urgent to maintain stable performance of EMI shielding films. In this work, we adopt the reactions between aldehyde-modified diamine monomers and dianhydride monomers with dynamic imine bond to successfully prepare a self-healing PI (SHPI) film. Benefit from dynamic imine and imide bond, the SHPI film possessed excellent thermal stability (T 5 % =527.7°C), tensile strength (72 MPa) and self-healing efficiency (94.4 %). As protecting coating layer, the SHPI film was able to maintain the commercial aluminized polyimide (PI/Al) film with good EMI shielding performance in acid environment. The electromagnetic shielding film with self-healing coating still had average EMI shielding effectiveness value of 44.5 dB after exposed to 10 % concentration nitric acid solution for 30 min. It is noteworthy that when damaged by external forces, the electromagnetic shielding film with self-healing coating could achieve rapid healing, while the tensile strength was up to 87 MPa and the self-healing efficiency reached 92.5 %. This work provided an effective self-healing protective layer for EMI shielding material against corrosion in acidic environments and damage from external pressures.
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高影响因子
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
·
2025
·
IF 14.3
Yugen Wang,Jianwei Li,Yuanyuan Zhong,Jiahao Kang,Bilin Zhang,Zhonglei Ma,Qiangli Zhao
The rapid development of modern 5G technology has significantly increased the demand for multifunctional electromagnetic interference (EMI) shielding and wave-absorbing materials. Hence, a densification strategy was proposed to fabricate multifunctional rigid polyimide (PI) composite foam. As a result, the composite PI foam exhibits excellent mechanical properties, with tensile and bending strengths of 4.7 and 21.1 MPa, respectively. Moreover, the composite PI foam achieves a promising EMI shielding performance with a high absorption coefficient ( A ) of 0.71, coupled with an X-band (8.2–12.4 GHz) EMI rating of 44 dB (2 mm) due to its high conductivity (20.29 ms/mm). Satisfyingly, the composite PI foam also has an optimal reflection loss (RL) of up to −46.4 dB and an effective absorption bandwidth (EAB) (RL < −10 dB) that covers the entire X-band. Meanwhile, the fabricated foam demonstrates a Joule heating performance of 89.2°C under supply voltages (3–9 V) and rapid response time (within 20 s) for stable and reproducible performance in long-term cycling. This work provides a versatile strategy for the development of lightweight and high-strength materials for EMI shielding and microwave absorption, demonstrating great potential for aerospace, microelectronics, and energy conversion applications.
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JOURNAL OF POWER SOURCES
·
2024
·
IF 8.1
Kangjie Zhou,Yongkang Fang,Minxian Bao,Wei Fan,Jianguo Ren,Peng He,Longsheng Zhang,Tianxi Liu
Developing fast-charging lithium metal battery (LMB) with high specific capacity arouses enormous attentions. Unfortunately, during the operation of fast-charging LMB, substantial amount of Joule heat generated within battery often induces inhomogeneous heat accumulation that concomitantly deteriorates the lithium dendrite growth issues, resulting in rapid capacity fading and potentially fatal thermal runaway. It is critically essential to develop advanced separator that possesses high ionic conductivity , effective dendrite inhibition and self-extinguishing property for fast-charging LMB with high-safety. Here, we report a facile approach to fabricate polyimide composite separator (denoted as PIFAP), where the polyimide fiber (PIF) membrane is sandwiched by aerogel layers of polyimide/ammonium polyphosphate composite. Notably, compared with PIF, the PIFAP features significant enhancement in flame retardance, electrolyte affinity, electrolyte adsorption and ionic conductivity . Moreover, beneficiating from the aerogel layers with uniform nanopores of ∼100 nm, the optimized PIFAP separator can enable homogeneous lithium deposition, achieving a dendrite-free lithium deposition on the surface of anode for over 1600 h, superior to the PIF and Celgard separators. The resulting “LiFePO 4 /PIFAP/Li” cell can exhibit a remarkably high cycling stability with 99.1 % of capacity retention after long-term cycling at a current density of 10 C.
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Journal of Energy Storage
·
2024
·
IF 8.9
Shengjun Peng,Ruizhi Wang,Zhongshuai Liang,Xianfeng Du
Polymer-based composites with multilayer structure were emerging as an effective way to solve the contradiction between high breakdown strength and large permittivity in past decades. However, the incorporating layers in conventional multilayer composite films are usually inorganic thick films, which is not beneficial for the retention of excellent mechanical properties of the polymer matrix. In this work, the multilayer films consisting of micrometer polyimide (PI) and nanoscale TiO 2 layer were prepared by spin-coating and atomic layer deposition (ALD), respectively. Carrier migration in PI-TiO 2 multilayer films was hindered effectively by the interfacial barrier, as indicated by the results of the Pulsed Electro-Acoustic (PEA) tests. Compared to pure PI, both the permittivity, dielectric loss and breakdown strength were optimized in the PI-TiO 2 multilayer films. A satisfactory discharge energy density of 6.77 J cm −3 (efficiency >90 %) was obtained in the multilayer films, which is about 5 times higher than that of pure PI. The strategy of constructing heterogeneous interfaces by incorporated nanoscale TiO 2 layers is promising for designing high performance capacitors in practical application.
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高影响因子
NANOTECHNOLOGY
·
2024
·Vol. 35
·期 47
·475706
·
IF 2.9
Wenrui Li,Xiong Yang,Changchun Qi,Yucheng Zhang,Yibo Dong,Xin Zhao,Zhiliang Gao,Na Feng,Baipeng Song,Guan-Jun Zhang
The exploration of deep space significantly increases the probability of spacecraft failures due to surface electrostatic discharge, which imposes higher vacuum insulation protection requirements on polyimide (PI), the external insulation material of spacecrafts. To address this challenge, this study proposes using silane coupling agent KH550 for organic grafting treatment of Cr2O3 nanoparticles, which are then used to dope and modify PI to enhance the vacuum surface insulation of PI films. The KH550 grafting improves the interface strength between the fillers and the matrix, allowing the fillers to be uniformly dispersed in the matrix. Compared to pure PI films, the prepared PI-Cr2O3@KH550 composite films exhibit significantly enhanced vacuum surface flashover voltage, improved surface/volume resistivity, and dielectric properties. The results demonstrate that PI composite films with 0.8% by mass of Cr2O3@KH550 show the most notable performance improvement, with the DC flashover voltage and impulse flashover voltage in vacuum increasing by 20.7% and 27.8%, respectively. The doping of chromium oxide nanoparticles introduces more deep traps into the PI films and reduce the surface resistivity. The higher deep trap density inhibits charge migration, thereby alleviating secondary electron emission and surface electric field distortion. Simultaneously, the lower surface resistivity facilitates dissipating surface charges and improves the surface insulation. These findings are of significant reference value for promoting the enhancement of aerospace insulation performance.
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高影响因子
ACS Applied Polymer Materials
·
2024
·
IF 4.4
Yanan Liu,Ming Hao,Xiaodong Hu,Zhijun Chen,Bo Yang,Yanbo Liu,Xiaoxiao Wang,Yen Wei
Interfacial solar steam generation has been regarded as a promising method to produce freshwater from seawater. Nevertheless, achieving simultaneous optimization of high evaporation efficiency along with stability and durability remains a substantial obstacle for polyimide (PI)-based solar evaporators. Herein, a hierarchically structured PI/MXene composite aerogel was prepared by electrostatic spinning, freeze-drying, and thermal imidization. The combination of PI nanofibers and MXene endows the hybrid aerogels with three-dimensional porous structures, intriguing hydrophilicity, and high light absorption, resulting in augmented light-to-heat conversion efficiency. Furthermore, the PI/MXene composite aerogel exhibits an excellent water evaporation rate of 1.459 kg m–2 h–1 under 1 sun with a high photothermal conversion efficiency of 95.6%. The PI/MXene composite aerogel possesses distinct salt resistance, eminent structural stability, and remarkable cycling stability with an evaporation rate of 1.24 kg m–2 h–1 over 10 cycles. This work provides a prospective strategy for constructing highly efficient solar-powered generator with stable performance for practical application in seawater desalination.
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JOURNAL OF ELECTRONIC MATERIALS
·
2024
·Vol. 53
·期 7
·3490-3502
·
IF 2.2
Shao Zhongjie,Liu Yaning,Yang Da,Li Longfei,Xia Yang,Zhang Lihui,Tong Bo,Wang Bingjia,Zhao Yong,Xiao Zhen
Carbon-based conductive polymer composites (CPCs) have significant potential for fabricating low-cost and high-performance flexible electric heating films in deicing applications. However, the inferior high-temperature resistance and low heating power density seriously restrict their large-scale commercial application. Herein, a series of polyimide (PI)/carbon black (CB) composite electrothermal films with excellent high-temperature stability and high-power density are prepared by a simple slurry coating method. With successfully introducing the high-temperature resistance and high mechanical strength PI as polymer matrix, the PI/CB composite electrothermal films with a low percolation threshold of 10.8% have a broad operating temperature ranging from 40°C to 270°C under low applied voltages (< 60 V) at room temperature. Impressively, these PI/CB composite electrothermal films with a uniform thin thickness of 45 μm exhibit high operating temperature (> 200°C), rapid heating response speed (< 10 s), remarkable long-term working stability, and superior low-temperature operating reliability even at −30°C. The simulated deicing experiment indicates that the PI/CB composite electrothermal film dislodges an ice cube (thickness = 10 mm) within 280 s. This work not only provides a universal strategy for the design and fabrication of high-operating-temperature CPCs, but also verifies the great potential for use in deicing applications. Graphical Abstract
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危险品化学品经营许可证（带存储）