Small
·
2018
·Vol. 14
·期 45
·1802479
·
IF 9.598
Ji Liu,Hao-Bin Zhang,Xi Xie,Rui Yang,Zhangshuo Liu,Yafeng Liu,Zhong-Zhen Yu
2D transition metal carbides and nitrides (MXenes) have gained extensive attention recently due to their versatile surface chemistry, layered structure, and intriguing properties. The assembly of MXene sheets into macroscopic architectures is an important approach to harness their extraordinary properties. However, it is difficult to construct a freestanding, mechanically flexible, and 3D framework of MXene sheets owing to their weak intersheet interactions. Herein, an interfacial enhancement strategy to construct multifunctional, superelastic, and lightweight 3D MXene architectures by bridging individual MXene sheets with polyimide macromolecules is developed. The resulting lightweight aerogel exhibits superelasticity with large reversible compressibility, excellent fatigue resistance (1000 cycles at 50% strain), 20% reversible stretchability, and high electrical conductivity of ≈4.0 S m −1 . The outstanding mechanical flexibility and electrical conductivity make the aerogel promising for damping, microwave absorption coating, and flexible strain sensor. More interestingly, an exceptional microwave absorption performance with a maximum reflection loss of −45.4 dB at 9.59 GHz and a wide effective absorption bandwidth of 5.1 GHz are achieved.
研究领域:
材料科学
·
物理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
EUROPEAN POLYMER JOURNAL
·
2023
·
IF 6
Jia-xin Ma,Li-li Yuan,Sheng-nan Fan,Li-zhe Wang,Bin Jia,Hai-xia Yang,Shi-yong Yang
Negative-tone photosensitive polyimides (n-PSPI) with high transparency at visible wavelength region (400–700 nm) were prepared by dissolving photosensitive polyimide precursor -poly(amide ester)(PAE) resins, photoinitiator, photocrosslinker and other additives in organic solvents. The PAE resins were synthesized by polycondensation of a fluorinated aromatic diamine with an aromatic diester dichloride or its mixture. The n-PSPI coating solutions showed good photolithographic performance with resolution of 8 µm (via) and 7 µm (line) at 5 µm of the thermally cured film thickness. After thermally cured at 350 °C/1h, the typical PSPI film exhibited excellent thermal properties with T g of 344 °C and T d5 of 525 °C, respectively. The mechanical properties with elongation at breakage of as high as 42.2% and tensile strength of 133.7 MPa were also measured. Additionally, the thermally cured PSPI films exhibited excellent transparency with UV cuttoff wavelength of 362 nm, transmittance of 90.5% at 450 nm, and 95.5% at 550 nm, as well as yellowness indices of less than 6.55. Furthermore, theoretical simulations were used to prove that trifluoromethyl group in the backbone structure of PSPI precursor resin can effectively improve the transparency of PSPI films.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Polymer Materials
·
2023
·
IF 5
Yanyan Wang,Shuaishuai Liu,Chao Xiao,Miao Jiang,Xin Ding,Hui Zhang,Kang Zheng,Lin Chen,Xingyou Tian,Xian Zhang
Polyimide (PI) films with high out-of-plane thermal conductivity are highly desirable for effectively alleviating thermal failure in advanced flexible electronics. However, it is still a great challenge to achieve high out-of-plane thermal conductivity with a low filler content by a simple method. Herein, an Ag-coated PI microsphere (PIM@Ag) as a thermally conductive filler with a considerable heat-transfer path in the out-of-plane direction is prepared to improve the out-of-plane thermal conductivity of the PI film. Because of the introduction of thermal welding between Ag nanoparticles during thermal imidization further eliminating the interface thermal resistance, the resultant PI/PIM@Ag composite film exhibits a high out-of-plane thermal conductivity of 1.2 Wm–1K–1 with an ultralow Ag content of 6.08 wt % and a superior tensile strength of 124.0 MPa compared to 78.9 MPa of a pure PI film. Practical application and comsol simulation results verify that the PI/PIM@Ag composite film has excellent heat dissipation ability for a chip. This work provides an idea for improving the out-of-plane thermal conductivity of polymers with low filler contents.
研究领域:
材料科学
·
电子工程
·
热传导
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2016
·
IF 7.145
Junzong Feng,Xin Wang,Yonggang Jiang,Dongxuan Du,Jian Feng
Polyimide aerogels for low density thermal insulation materials were produced by 4,4′-diaminodiphenyl ether and 3,3′,4,4′-biphenyltetracarboxylic dianhydride, cross-linked with 1,3,5-triaminophenoxybenzene. The densities of obtained polyimide aerogels are between 0.081 and 0.141 g cm–3, and the specific surface areas are between 288 and 322 m2 g–1. The thermal conductivities were measured by a Hot Disk thermal constant analyzer. The value of the measured thermal conductivity under carbon dioxide atmosphere is lower than that under nitrogen atmosphere. Under pressure of 5 Pa at −130 °C, the thermal conductivity is the lowest, which is 8.42 mW (m K)−1. The polyimide aerogels have lower conductivity [30.80 mW (m K)−1], compared to the value for other organic foams (polyurethane foam, phenolic foam, and polystyrene foam) with similar apparent densities under ambient pressure at 25 °C. The results indicate that polyimide aerogel is an ideal insulation material for aerospace and other applications.
研究领域:
材料科学
·
航空航天工程
✓ 已验证
DOI
高影响因子
LANGMUIR
·
2025
·
IF 3.9
Anhui Yu,Zhiguang Guo
Droplet manipulation on functional surfaces is an urgent problem to be solved. Fast and precise droplet manipulation plays an important role in many applications, such as microreactors and microfluidics. Although numerous techniques have been developed to manipulate droplets by injecting external stimuli, it remains a challenge to achieve high-precision, high-sensitivity, and fast droplet manipulation on smart, slippery response surfaces. Here, we report an intelligent slippery photopyroelectric response near-infrared-induced MXene-barium titanate/polyimide (SFMBPI) membrane. By using local near-infrared radiation (NIR), we can precisely control the droplet transport on the SFMBPI membrane, and SFMBPI uses electrospinning technology to better lock the dimethylsilicone oil, reducing the loss during the control process. Moreover, due to the presence of the pyroelectric layer, double external stimuli can be achieved. The thermal stimulation of the photothermal layer and the charge action of the pyroelectric layer make the manipulation of droplets on the SFMBPI surface more efficient and faster. Moreover, the experiment of negative gravity transport at an inclination angle of 6° demonstrates that the existence of the pyroelectric layer results in a greater driving force on the droplets, which can be more widely used. In addition, by inducing the direction of the NIR, programmable droplet transport and droplet merging can be achieved. Also, the SFMBPI membrane can be used for underwater bubble manipulation. This precise manipulation of droplets on the surface of SFMBPI membranes can be widely used in other fields, such as microfluidics.
研究领域:
材料科学
·
微流控技术
·
表面科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2025
·
IF 6.2
Zhi Li,Kai Shen,Min Hu,Miao Liu,Fang Zhou,Ming Li,Qiong Liu,Xiaoxu Wu,Weiwang Chen
Polyimide aerogels (PIAs) have extensive application prospects in numerous fields for their appealing characteristics, including low density, superior thermal stability, high flexibility, and remarkable mechanical properties. However, the thermal safety of polyimide aerogels in practical applications has been neglected, the pyrolysis behaviors and reaction kinetics need to be clarified. In this work, PIAs with different repeat units from 10 to 60 were prepared using the sol-gel method, and the effect of repeat unit on the basic properties, microstructure, and thermal stability of polyimide aerogel was studied. The PIAs with a repeat unit of 40 have the lowest density, thermal conductivity, radial shrinkage, the highest porosity, the largest specific areas, and so on. Furthermore, the pyrolysis process and products of PIA were analyzed by TG-FTIR-MS. The pyrolysis kinetic parameters were calculated by model-free method and the predicted reaction model was chosen by CR and Malek method. The calculated kinetic parameters are in good agreement with the experimental data at different heating rates, which can guide the pyrolysis behavior and thermal safety of polyimide aerogels.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
ELECTROCHEMISTRY COMMUNICATIONS
·
2015
·
IF 4.847
Fei Xu,Jintao Xia,Wei Shi
Two polyimides using redox-active anthraquinone group as the connection unit are synthesized and characterized as cathodes for sodium secondary batteries. Sodium cells based on these two polyimide cathodes provide reversible capacities as high as 165 and 192 mAh g − 1 , respectively, with excellent cyclabilities. A reversible four-electron transfer can occur for both of these two polyimides in the voltage range of 1.2–3.2 V with cyclic voltammetry measurements. These results suggest that anthraquinone is a promising connection unit for designing polyimide-based cathodes with high capacities for sodium secondary batteries.
研究领域:
储能
·
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
CHINESE JOURNAL OF POLYMER SCIENCE
·
2020
·Vol. 38
·期 8
·867-876
·
IF 3.154
Chen Qi,Wang Shun,Qin Feng,Liu Kuan,Liu Qian,Zhao Qing,Wang Xing-Yi,Hu Yan-Hong
Polyimide (PI) synthesized from aromatic diamine and dianhydrides via two-step poly-condensation method was highly soluble in TGDDM (MY-720) and DGEBA (E-51) at desirable temperature. TGDDM-PI (M-PI) and DGEBA-PI (E-PI) composites within 0.5%-3% PI loading could be prepared without organic solvent. On the cryogenically fractured surfaces of M-PI and E-PI composites, no obvious heterogeneous phase was observed by SEM. The mechanical properties were promoted significantly by PI, especially for impact strength. Adding 2% PI-2W into MY-720 and E-51 composites, the impact strength increased to 21 and 51 kJ/m 2 , the tensile strength increased by 62% and 19%, and the flexural strength by 18% and 13%, respectively, with slight increases in tensile modulus. These results were related to the promotion in plasticity of composites and changes in fragile→ductile fracture mode. Moreover, T g and thermal stability of M-PI and E-PI were increased effectively.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ELECTROCERAMICS
·
2019
·Vol. 43
·期 1
·117-122
·
IF 1.966
Cheng Yatong,Niu Yujuan,Xiang Feng,Chang Panpan,Wang Hong
Ba 3 Co 2 Fe 24 O 41 (Co 2 Z)/polyimide(PI) composites were synthesized via in-situ polymerization process, using the micron-sized Co 2 Z particles prepared by the solid-state reaction. X-ray diffractometer (XRD) pattern shows the existence and purity of the aimed phase. Scanning electron microscope (SEM) images show that the Co 2 Z particles are uniformly dispersed in the composites. The testing results of dielectric properties of composites reveal that the dielectric constants of the composites increase with the Co 2 Z content increasing. The frequency-dependent dielectric loss shows that the dielectric loss of samples has the same trend, and that a peak can be observed at about 10 MHz. The saturation magnetization (Ms) of composites depends on the ferrite content, and the Ms. value can reach 8.9 emu/g when the ferrite content is 40 wt% in Co 2 Z/PI composites. Additionally, the coercivity (Hc) of composites show almost no change as the ferrite content increasing, about 100 Oe. The results indicate that the obtained magnetic dielectric composites are new candidates for antenna applications.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2017
·
IF 7.504
Jiulin Shen,Fu Li,Zhonghuan Cao,David Barat,Guoli Tu
Here we demonstrate a simple and effective method of fabricating polymeric scattering substrate for flexible organic light-emitting diodes (OLEDs) that require no costly patterning, etching, or molding processes, aspects that are desirable for the commercialization of large-scale lighting panels. Systematic study of the influences of relative index of refraction, particle size, and doping concentration on transmittance and haze of transparent colorless polyimide (cPI) films was carried out. It was found that the reduction of transmittance and haze of the doped films decreases along with the decrease of the difference of refractive index between the particles and polymer matrix, and it could be compensated by the increase of particle size or doping concentration.
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Applied Materials & Interfaces
·
2013
·
IF 5.008
Ting Huang,Yuanshi Xin,Tongsheng Li,Steven Nutt,Chao Su,Haiming Chen,Pei Liu,Zuliang Lai
By taking advantage of design and construction of strong graphene–matrix interfaces, we have prepared modified graphene/polyimide (MG/PI) nanocomposites via a two-stage process consisting of (a) surface modification of graphene and (b) in situ polymerization. The 2 wt % MG/PI nanocomposites exhibited a 20-fold increase in wear resistance and a 12% reduction in friction coefficient, constituting a potential breakthrough for future tribological application. Simultaneously, MG also enhanced thermal stability, electrical conductivity, and mechanical properties, including tensile strength, Young’s modulus, storage modulus, and microhardness. Excellent thermal stability and compatibility of interface, strong covalent adhesion interaction and mechanical interlocking at the interface, as well as homogeneous and oriented dispersion of MG were achieved here, contributing to the enhanced properties observed here. The superior wear resistance is ascribed to (a) tribological effect of MG, including suppression effect of MG in the generation of wear debris and protective effect of MG against the friction force, and (b) the increase in mechanical properties. In light of the relatively low cost and the unique properties of graphene, the results of this study highlight a pathway to expand the engineering applications of graphene and solve wear-related mechanical failures of polymer parts.
研究领域:
材料科学
·
表面工程
·
高分子化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MACROMOLECULAR CHEMISTRY AND PHYSICS
·
2021
·Vol. 222
·期 19
·2100197
·
IF 2.527
Yinfu Luo,Long Ni,Cheng Zhang,Liwei Yan,Huawei Zou,Shengtai Zhou,Mei Liang
Lightweight and excellent thermal stability hollow polyimide (PI) microspheres play an important role in high-end engineering applications such as aerospace, marine use among others. Herein, a simple approach is proposed to scalable fabrication of hollow PI microspheres with controllable sizes by powder foaming method combined with gradient heating strategy. The diameter of PI microspheres ranges from 295.5 to 1479.6 µm with a wall thickness of ≈7.78 µm. Interestingly, the diameter of PI microspheres exhibits a good correlation with the size of polyester ammonium salt (PEAS) particles. The hollow PI microspheres demonstrate excellent heat resistance with a bulk density ranging from 56.9 to 132.2 kg m –3 . Furthermore, PI microspheres could be readily converted into carbon microspheres without destroying their original integrity, which shows potential applications in preparing multifunctional composites. The proposed method is easily scalable which can be adopted to fabricate hollow PI microspheres at large quantities for industrial applications.
研究领域:
材料科学
·
航空航天工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）