POLYMER JOURNAL
·
2015
·Vol. 48
·期 2
·169-175
·
IF 1.653
Wu Qi,Pan Lili,Wang Haijiang,Deng Wenxiu,Yang Guangjie,Liu Xikui
Polymeric aerogels have great potential in numerous fields because of their unique combination of thermal and electrical properties, and lightweight porous structures. However, the laborious supercritical CO 2 drying method required for making these aerogels limits their commercial availability. Here we demonstrate a green and scalable method for preparing high-performance polyimide (PI) aerogels using a low-boiling-point solvent mixture of tetrahydrofuran/methanol, and especially using sublimation drying instead of laborious supercritical CO 2 drying. The monolithic and powder polyamic acid aerogels can be prepared easily; after thermal imidization, PI aerogels with nanofibrous morphology, low density and high thermal stability can be obtained. This green, scalable and cost-effective process will facilitate the application of high-performance PI aerogel materials in many fields, in particular those in which high-temperature resistance is important.
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
CHEMISTRY OF MATERIALS
·
2018
·
IF 9.89
Xin Ye,Yang Liu,Quanxiang Han,Chao Ge,Shuangyue Cui,Leilei Zhang,Xiaoxin Zheng,Guangfeng Liu,Jie Liu,Duo Liu,Xutang Tao
Organic single crystals manifest the intrinsic physical properties of materials. However, traditional growth of organic single crystals is limited by low solubility from solutions or complexity from physical vapor deposition. Here we report a new method to grow organic single crystals by microspacing in-air sublimation, which avoids costly vacuum system and time-consuming procedures and is practical for a wide range of organic crystals. In situ crystal growth observation revealed an unprecedented vapor-to-melt-to-crystal mechanism, resulting from the micrometer scale spacing distance between the source and the growth position. FET devices based on the rubrene crystals directly grown on Si/SiO2 substrate exhibited higher mobility than the best record using SiO2 as the gate dielectric. This effective organic crystal growth technique can be affordable and handled for almost every lab, which may be beneficial for future research and application of organic crystals.
研究领域:
材料科学
·
有机电子学
✓ 已验证
产品关联
DOI
高影响因子
Catalysts
·
2020
·Vol. 10
·期 3
·306
·
IF 3.52
Chunling Wu,Yang Luo,Kai Zhao,Xiaobing Yu,Xian Zhang,Xuqiang Guo
In this paper, direct coal liquefaction residue was prepared from Shen-dong coal, and the solubility of the residue in five organic solvents was studied. Then, an experimental device was set up to recover molybdenum (Mo) compounds from the direct coal liquefaction residue after extraction, and the influences of sublimation temperature and duration on recycling efficiency were examined. The recycled Mo-based products were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and a thermal analyzer. The results reveal that the optimum extraction conditions were obtained through ultrasonic extraction with a quinoline solvent and the highest recycling efficiency occurred for sublimation at 900 °C for 30 min. The recycled products are identified to be α-MoO3crystals. Moreover, the α-MoO3crystal is thermally stable before the temperature reaches its melting point.
研究领域:
化学工程
·
材料科学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Yuwei Wang,Xiaoyan Yuan,Zhuoying Ping,Dan Wei
One-dimensional materials are broadly applied in electromagnetic wave (EMW) absorption due to their fast electron transport paths. Herein, SiC/C nanofibers (SiC/C NFs) with rough surface and fluffy structure were prepared by electrospinning, using zinc acetylacetone as a structural modifier. The morphology and microstructure of the as-prepared fibers were changed by Zn sublimation during heat treatment process, leading to significantly improve their dielectric parameters and EMW absorption performance. The minimum reflection loss (RL, dB) of the SiC/C NFs/paraffin with a filling ratio of 15 wt% was −46.77 dB, and effective absorption bandwidth (EAB, RL < −10 dB) reached 5.84 GHz at 1.96 mm. The delightful performance was mainly attributed to the fluffy microstructure caused by the Zn sublimation, the fast electron transport paths established by the fibers, and the enhanced polarization loss brought by effective heterogeneous interfaces. Therefore, a referable strategy was put forward structural engineering for the absorber of SiC/C NFs.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
高影响因子
DYES AND PIGMENTS
·
2019
·
IF 4.018
Huanhuan Li,Hong-Fei Qian,Gaofeng Feng
A novel approach has been established for accessing structurally diverse azo disperse dyes with improved fastness properties by employing an Ugi four-component reaction (Ugi-4CR). The process includes three steps: (1) Ugi-4CR of aniline, cyclohexyl isocyanide, formic acid , and an aromatic aldehyde; (2) selective hydrolysis of amide functionality in the Ugi product; and (3) coupling the hydrolysis product with an aryl diazonium salt. Employing Ugi-4CR herein had advantages over easily controlling the molecular weight/size of the dye. Six new azo disperse dyes were synthesized and their structures were fully characterized by 1 H NMR, 13 C NMR, MS, and FT-IR. It was found that the washing and sublimation fastness properties of the obtained azo disperse dyes on both poly (ethylene terephthalate) (PET) and nylon fibers were remarkably improved as compared with conventional C.I. Disperse Orange 3. The improved fastness properties should be attributed to the moderately increased molecular weight/size and the amide functionality introduced in Ugi-4CR.
研究领域:
化学
·
染料合成
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Dedong Guo,Shuheng Dong,Qingzhou Wang,Huixin Yu,Eun-Seong Kim,Qing Xu,Ho-Kun Sung,Zhao Yao,Yuanyue Li,Nam-Young Kim
The development of a highly sensitive and wide-range flexible pressure sensor is great significant to realize the practical applications in human–computer interaction, health monitoring, and motion detection. Here, a dielectric layer of nano-cracked polyvinyl pyrrolidone (PVP) hierarchical nanofiber membrane (HNM) was fabricated by sublimating BiI 3 from an electrospun BiI 3 /PVP composite nanofiber membrane (NM) via one-step annealing process. The upper and lower electrodes of porous laser-induced graphene (LIG) were produced through the engraving process on polyimide (PI) substrates. Subsequently, a flexible capacitive pressure sensor was constructed by assembling the middle PVP HNM dielectric layer with upper and lower LIG electrodes, which demonstrates enhanced sensitivity and detection range for motion posture recognition. Experimental results indicate that compared with traditional PVP NM-based pressure sensor, the assembled sensor in this work exhibits 22 times higher sensitivity (at 2–100 kPa) and 4 times wider detection range (0–200 kPa). Additionally, the sensor boasts a fast response/recovery time of 29/41 ms, an exceptionally low detection limit of 2.7 Pa, and an outstanding stability of 3000 cycles. With the aid of a convolutional neural network (CNN) algorithm, a shooting posture recognition system was developed by multiple sensors to accurately identify (accuracy: 93.89 %) and guide the shooting postures of basketball players.
研究领域:
材料科学
·
电子工程
·
人工智能
✓ 已验证
产品关联
DOI
高影响因子
Journal of the American Chemical Society
·
2023
·
IF 15
Shasha Liu,Haoran Li,Susu Fang,Weigao Xu,Wenbing Hu,Wei Wang
The Leidenfrost effect describes a fascinating phenomenon in which a liquid droplet, when deposited onto a very hot substrate, will levitate on its own vapor layer and undergo frictionless movements. Driven by the significant implications for heat transfer engineering and drag reduction, intensive efforts have been made to understand, manipulate, and utilize the Leidenfrost effect on macrosized objects with a typical size of millimeters. The Leidenfrost effect of nanosized objects, however, remains unexplored. Herein, we report on an unprecedented Leidenfrost effect of single nanosized sulfur particles at room temperature. It was discovered when advanced dark-field optical microscopy was employed to monitor the dynamic sublimation process of single sulfur nanoparticles sitting on a flat substrate. Despite the phenomenological similarity, including the vapor-cushion-induced levitation and the extended lifetime, the Leidenfrost effect at the nanoscale exhibited two extraordinary features that were obviously distinct from its macroscopic counterpart. First, there was a critical size below which single sulfur nanoparticles began to levitate. Second, levitation occurred in the absence of the temperature difference between the nanoparticle and the substrate, which was barely possible for macroscopic objects and underscored the value of bridging the gap connecting the Leidenfrost effect and nanoscience. The sublimation-triggered spontaneous takeoff of single sulfur nanoparticles shed new light on its further applications, such as nanoflight.
研究领域:
材料科学
·
纳米技术
·
物理学
✓ 已验证
DOI
高影响因子
Materials Research Express
·
2017
·Vol. 4
·期 7
·075020
·
IF 1.068
Bingying Gao,Shaoxiang Lu,Mulenga Kalulu,Olayinka Oderinde,Lili Ren
To replace traditional preparation methods of silica aerogels, a small-molecule 1,2-epoxypropane (PO) has been introduced into the preparation process instead of using ammonia as the cross-linking agent, thus generating a lightweight, high porosity, and large surface area silica aerogel monolithic. We put forward a simple solution route for the chemical synthesis of silica aerogels, which was characterized by scanning electron microscopy (SEM), TEM, XRD, FTIR, thermogravimetric analysis (TGA) and the Brunauer–Emmett–Teller (BET) method In this paper, the effect of the amount of PO on the microstructure of silica aerogels is discussed. The BET surface areas and pore sizes of the resulting silica aerogels can be freely adjusted by changing the amount of PO, which will be helpful in promoting the development of silica aerogels to fabricate other porous materials with similar requirements. We also adopted a new organic solvent sublimation drying (OSSD) method to replace traditional expensive and dangerous drying methods such as critical point drying and freeze drying. This simple approach is easy to operate and has good repeatability, which will further facilitate actual applications of silica 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
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
·
2014
·Vol. 53
·期 38
·10147-10149
·
IF 11.336
Lili Ren,Sumin Cui,Fengchao Cao,Qinghui Guo
Inorganic oxide aerogels have unique thermal, optical, electrical, magnetic, and chemical properties, which result in them potentially having a broad range of applications. However, their preparation is commonly based on a supercritical drying method, which greatly limits real applications of aerogels and their commercialization. Here we demonstrate a general method for drying wet gels to form aerogels that is based on the sublimation of organic solvent. The organic solvent must have a low surface tension, undergo sublimation easily, and have a high freezing point to allow the rapid synthesis of monolithic inorganic oxide aerogels under vacuum conditions. This cost-effective process will facilitate application of aerogel materials. This approach may also be used for the preparation of other porous materials, whose theoretical and practical applications should be investigated. Graphical Not cracking up : A drying method based on the sublimation of organic solvent allows the rapid synthesis of the monolithic inorganic oxide aerogels without cracks from wet gels. The method proceeds by endothermic evaporation of organic solvent at the outer surface followed by sublimation of solidified solvent (see picture).
研究领域:
材料科学
·
纳米科技
·
化学工程
·
功能材料
✓ 已验证
DOI
高影响因子
CRYSTAL GROWTH & DESIGN
·
2024
·
IF 3.2
Fei Wang,Jianhong Liu,Yuxin Xie,Xiaohua Chen,Lianchao Liu,Xin He,Xinghua Zhao
Tetramethylpyrazine (TMP) is used clinically to treat cardiovascular disease and ischemic cerebrocardial vascular disease. However, the high sublimation tendency of TMP leads to its physical instability. In this study, we successfully synthesized and comprehensively characterized four cocrystals formed by TMP with cinnamic acid and its derivatives. These cocrystals effectively mitigated the sublimation tendency of TMP, demonstrating their potential for stabilizing the active pharmaceutical ingredient. Through detailed density functional theory calculations, we systematically investigated the stability mechanisms of these cocrystals, revealing that both the number and distribution of polar groups, governing the formation of strong hydrogen bonds, and the presence and distribution of weak hydrogen bonds jointly contribute to their stability. Furthermore, we explored the intricate relationships among cocrystal stability, hydrogen bonding patterns, and crystal growth mechanisms, offering novel avenues for the rational design and optimization of cocrystals in drug development. This study not only enhances our understanding of cocrystal stability and crystal growth mechanisms but also provides valuable insights for drug innovation, paving the way for future theoretical guidance and practical references in drug design and optimization.
研究领域:
药学
·
材料科学
·
理论化学
·
药物开发
✓ 已验证
产品关联
DOI
高影响因子
DYES AND PIGMENTS
·
2016
·
IF 4.055
Gaofeng Feng,Hong-Fei Qian,Gang Bai,Yan-Chun Liu,Ling-Ling Hu
A series of new kinds of diester/diurethane tethered azo disperse dyes were synthesized through the reaction between the hydroxyl group in disperse dyes, such as C. I. Disperse Red 1 ( 1a ), C. I. Disperse Red 13 ( 1b ), and C. I. Disperse Blue 106 ( 1c ), and terephthaloyl chloride or p -phenylene diisocyanate . Structures of these new dyes were fully characterized with NMR, MS, and FT-IR. Visible absorption measurement in DMF indicated that all new diester/diurethane tethered dyes exhibited a little shorter maximum absorption wavelength and much higher molar extinction coefficient than their prototypes. Moreover, the fastnesses to wash and sublimation of dyeing on polyurethane fibre were dramatically improved due to the dye's moderately increased molecular size. It is an attractive new strategy to synthesize a library of tethered dyes with improved fastness properties using various different tethering agents or disperse dyes.
研究领域:
化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2024
·
IF 5.8
Hui Li,Rui Da,Li-Quan Yao,Hu Li,Peng Tang,Jin-Rui Cai,Li-Mei Lin,Shui-Yuan Chen,Dong Wei,Li-Ping Cai,Gui-Lin Chen
Sulfoselenide Sb 2 (S,Se) 3 , as a potential light-harvester, possesses a flexibly tunable bandgap of 1.1–1.7 eV to match solar radiation spectrum. However, the preparation of a homogenous Sb 2 (S,Se) 3 film is still challenging due to the different growth kinetics in sulfide and selenide compound, which consequentially leads to phase separation, lattice disorder and unfavored band level. This dilemma also occurs in the simple and well-established close space sublimation (CSS) method, and poses a devastating carrier recombination in Sb 2 (S,Se) 3 solar cells. Herein, alloyed powders of Sb 2 (S,Se) 3 are exquisitely synthesized by a thorough gas-solid reaction, delivering a uniform and single phase composition distribution as well as finely-tunable S/Se ratio. Compared with a physically mixed powder source (Sb 2 S 3 /Sb 2 Se 3 ), this alloyed Sb 2 (S,Se) 3 source allows for the fabrication of a homogeneous Sb 2 (S,Se) 3 thin film by CSS, rendering improved ( hk1 ) orientation, dense morphology, a more consistent longitudinal S/Se ratio, and enhanced energy level arrangement. These advancements contribute to enhance carrier transport and reduce carrier recombination. As a result, the efficiency of the solar cell is remarkably boosted from 2.59% to 5.46%, which is among of the highest PCE of full-inorganic Sb 2 (S,Se) 3 devices fabricated through the CSS method.
研究领域:
材料科学
·
能源技术
·
半导体物理
✓ 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）