JOURNAL OF MATERIALS SCIENCE
·
2022
·Vol. 57
·期 2
·1019-1035
·
IF 4.682
Wang Zhen,Tao Jie,Shen Yizhou,Liu Senyun
Composite film heater is becoming the focus of research in the deicing field, owing to its advantages of high electro-thermal efficiency and lightweight. In this work, a new composite film heater with ultralow conductive filler was designed and prepared by mixing insoluble ethyl vinyl acetate (EVA) and soluble polyvinylidene fluoride (PVDF) in dimethylformamide (DMF). It is common sense that many insoluble EVA fillers degrade mechanical properties due to the macro-interface defect. The molecular dynamic simulation indicated that interfacial blending regions were formed more easily between molten EVA and soluble PVDF on account of the similar solubility parameter and stronger adsorption energy between Vinyl acetate segmer and PVDF segmer. The semi-compatible system was favorable to eliminate the macro-interface defect between EVA and PVDF partially. The film heater showed better tensile strength, flexibility, and bending durability after heat treatment of 80 °C. Moreover, the film heater had an outstanding heating effect, fast electro-thermal response time, low-energy consumption, and excellent thermal cycling stability. It achieved the steady-state temperature of 117.4 °C and the heating rate of 1.348 °C/s when the ratio of PVDF to EVA was 1:1 and the amount of CNT was only 10% at 28 V. The optimal ratio of CNT and EVA could construct a double reticular structure, consists macroscopic and microscopic conductive network at the same time, thereby reducing the content of conductive filler significantly. Furthermore, the deicing experiment manifested that the icicle fell after 29 s at 28 V, much shorter than without loading current. The integrated CNT@EVA/PVDF composite film heater contributes to a better understanding of the low percolation effect and the distribution mechanism between molten EVA and soluble PVDF, which could conduce to the development of novel electro-thermal deicing film in future.
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PROGRESS IN ORGANIC COATINGS
·
2023
·
IF 6.6
Guoxu He,Menghui Wan,Zhihua Wang,Xi Zhou,Yanbao Zhao,Lei Sun
The discharge of oily effluents from industrial production and crude oil spills at sea result in significant water pollution, posing a major danger to the environment and human health. Due to the tiny droplet size, emulsion separation is a difficult task in the separation and purification of oily wastewater. Polydopamine (PDA) and TiO 2 nanoparticles were coated on the surface of polyvinylidene fluoride (PVDF) electrospun nanofibrous to increase surface roughness, and then the low surface energy substance octadecylamine (ODA) was grafted. As a result, a superhydrophobic PVDF@PDA/TiO 2 @ODA nanofibrous felts with a water contact angle of 168.1° has been developed. Because of their three-dimensional porous structure, the nanofibrous felts have a porosity of up to 72.9 %. The tensile strength of a series of reinforced PVDF@PDA/TiO 2 @ODA nanofibrous felts reaches 30.06 MPa, which is useful for maintaining the stability of the nanofibrous felts during the pressure separation. The oil and water in the emulsion are entirely separated due to the selective permeability induced by the strong superhydrophobic and superlipophilic properties. The separation efficiency of over 99 % and flow flux of above 1100 L·m −2 ·h −1 are achieved. The performance of the nanofibrous felts in inhibiting bacterial growth was then investigated, and it is found that a significant inhibition circle appeared in the flat dish diffusion method, with a bacteriostasis rate exceeding 99 %. This result demonstrates that PVDF@PDA/TiO 2 @ODA nanofibrous felts have excellent antimicrobial properties. Finally, UV–vis absorption spectroscopy was employed to demonstrate the good catalytic degradation of organic dyes by PVDF@PDA/TiO 2 @ODA nanofibrous felts. PVDF@PDA/TiO 2 @ODA nanofibrous felts have a variety of applications in the deep separation and purification of oily wastewater due to these characteristics.
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JOURNAL OF ELECTRONIC MATERIALS
·
2023
·Vol. 52
·期 11
·7193-7207
·
IF 2.1
Yuan ChongXiao,Zhang Chao,Yang Cheng,Wu Fuling,Xiao Shibing,Sun Huajun
Flexible wearable sensing devices are in great demand for self-powered systems. In this study, we fabricated fiber films of poly(vinylidene fluoride) (PVDF) matrix embedded with modified lead zirconate titanate nanoparticles (PZT NPs) using the electrospinning process. Each fiber film was cut into small pieces of 2 × 2 cm 2 , and pairs of pieces were pressed with a hot-pressing method. Modified PZT NPs with a high piezoelectric coefficient were embedded in PVDF fibers as a piezoelectric-reinforcing phase, which promoted the formation of the polar β phase in PVDF. The embedded PZT NPs affected the distribution of the polarized electric field and formed a local electric field between two PZT NPs, which promoted the polarization of PVDF, thereby enhancing the piezoelectric properties of PVDF/PZT NPs fiber films. The piezoelectric coefficient ( d 33 ) of the PVDF/PZT NPs fiber films embedding 4 wt.% PZT NPs showed the most significant enhancement, from 12 pC/N for neat PVDF to 21 pC/N, which is an approximately 75% improvement. The results of this work demonstrate the great potential application of piezoelectric composite fiber films in flexible wearable sensing devices.
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Science China-Technological Sciences
·
2023
·Vol. 66
·期 5
·1461-1470
·
IF 4.6
Xiang Xin,Chen DongYun,Li NaJun,Xu QingFeng,Li Hua,He JingHui,Lu JianMei
Although many superwetting materials have been designed for the treatment of oil-containing wastewater, separation strategies for oil-in-water systems containing bacteria have rarely been reported. Herein, poly(vinylidene difluoride)- and poly(lactic acid)-blended fibrous membranes loaded with silver and copper oxide nanoparticles were successfully prepared by a two-step method of electrostatic spinning and liquid-phase synthesis. The product membrane showed excellent super-oleophilic properties in air and hydrophobicity under oil. It could separate water-in-oil emulsion systems containing surfactants with an efficiency above 90%. More importantly, the nanoparticle-loaded fibers were characterized by material degradability and slowly released ions. The fibers exhibited excellent antibacterial activities against both gram-positive and -negative bacteria. This work provides a feasible strategy for water-in-oil emulsion separation and bacterial treatment of wastewater.
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高影响因子
COMBUSTION AND FLAME
·
2023
·
IF 4.4
Jie Ji,Heng Xu,Haozhe Li,Xiandie Zhang,Xiang Ke,Xinwen Ma,Xiaode Guo,Xiang Zhou
With the development of traditional aluminum(Al)-based nanothermites, some problems on account of the metal Al powder gradually emerged. Therefore, extensive research is devoted to exploring novel metal fuels to achieve better energy release effects. Titanium (Ti) powder is a potential metal fuel theoretically considering of reducibility and calorific value , but it has rarely been reported in the field of nanothermites. This paper put forward the design strategy by selecting as the metal fuel and polyvinylidene fluoride (PVDF) as oxidant. According to the hydrophilicity of Ti powders, the PVDF film encapsulation can effectively improve hydrophobicity and storage stability. Another advantage of PVDF film state is that it imparts excellent mechanical properties (yield strength of 30.5 MPa and elongation at break of 202.8 %). According to the results of thermal analysis, Ti increased the thermal stability of PVDF while accelerated its thermal decomposition rate. In ignition properties, Ti-PVDF films have the shortest ignition delay time (217 ms) lower than results reported in the literature of other nanothermites under the same conditions. In addition, the energy release process of ignition combustion is analyzed and verified in this paper. Therefore, Ti-PVDF energetic ignition material with diverse properties is expected to be applied in more fields not limited to nanothermites.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Junwei Chen,Qianwen Yu,Mingxia Wang,Dan Liu,Linfang Dong,Zhenyu Cui,Benqiao He,Jianxin Li,Feng Yan
The treatment of various oily wastewaters generated in human production and life has been a huge challenge in recent years. Responsive materials for controlled wettability surface have a great potential for oil-water separation. Inspired by the superior pH-responsive of poly (2-( N, N′ -dimethylamino) ethyl methacrylate) (PDMAEMA), a pH-responsive self-cleaning PVDF ultrafiltration membrane containing both carboxyl and tertiary amine groups were prepared by a simple grafting and co-blending method. The membrane fabrication process consisted of introducing 3-Dimethylaminopropylamine (DMPA) into the SMA side chain, resulting in the creation of the amphiphilic polymer DMPA@SMA. This polymer was then mixed with PVDF to produce DMPA@SMA/PVDF membranes. The optimized DMPA@SMA/PVDF membranes showed excellent superhydrophilicity/underwater superhydrophobicity, with a water contact angle of 0° and an underwater oil contact angle higher than 150° for crude oil. These endowed the as prepared membrane with a high pure water flux of 852 L·m −2 ·h −1 and anti-crude-oil-adhesion property. The separation efficiency exceeded 98% for various surfactant-stabilized oil-in-water emulsions, whether it’s positively charged emulsion or negatively charged emulsion. More interestingly, the carboxyl and tertiary amine groups presented the membrane with pH responsivity, and the membrane surface can be triggered by acid or alkali with self-cleaning performance. Strategy proposed in the present work offers a convenient and effective way to prepare membranes treating oil-in-water emulsions with either negative or positive charges.
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DIAMOND AND RELATED MATERIALS
·
2023
·
IF 4.1
Qin Wang,Huizi Li,Xiaojie Liu,Tingyao Du,Jianyu Guo,Siyong Zhang,Yan Lu
In this work, a carbon-based monolith with macroporous-mesoporous structure derived from polyvinylidene fluoride (PVDF) hollow fiber membranes is reported. The Co 2+ soaked PVDF hollow fiber membranes are treated with vinyltrimethoxysilane (VTMS) and calcined at relatively low temperatures (600 °C) to obtain a carbon-based material with a distinctive honeycomb porous structure . The VTMS treatment is the committed step, which provides a hard SiO 2 protective layer for the PVDF hollow fiber membrane during the calcination process to support the skeleton structure and prevent the macrostructure collapse and also plays a role in expanding mesopores. The obtained hierarchically porous structure can improve the electrochemical activity of the carbon-based material. In a three-electrode system, the specific capacitance of 701.0 F g −1 can be achieved at a current density of 1 A g −1 , and the retention rate is 112.1 % after 10,000 cycles at 10 A g −1 . The assembled quasi-solid-state symmetric supercapacitor can be operated in a 0–1.4 V voltage window, and it demonstrates an energy density of 26.3 Wh kg −1 at the power density of 349.9 W kg −1 .
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高影响因子
LANGMUIR
·
2023
·
IF 3.9
Yujia Tong,Changing Miao,Wenlong Ding,Fiona Hammond Quarcoo,Xiao Xiao,Hongjun Ji,Weixing Li,Xiaohui Ju
The current methods of constructing modification strategies for hydrophilic membranes are time-consuming, complex in operation, and poor in universality, which limit their application on membranes. In this work, inspired by the adhesion properties and versatility of caffeic acid (CA) and p-phenylenediamine (PPDA), a simple, rapid, and universal method was designed for the separation of oil-in-water emulsion by preparing a stable hydrophilic coating separation membrane. The preparation time of the membrane was shortened to 40 min. The developed PVDF–PCA/PPDA membrane showed superhydrophilic and underwater superoleophobic properties. When applied to petroleum ether-in-water emulsion, isooctane-in-water emulsion, and dodecane-in-water emulsion separation, the oil rejection was more than 99.0%. In the circulating separation of 10 g/L soybean oil-in-water emulsion, the oil rejection was more than 99.3%, and the highest flux was 1036 L·m–2·h–1. The prepared PVDF–PCA/PPDA membrane performed well in the separation test of oily wastewater. The proposed strategy is simple and rapid; it may become a universal method for preparing membranes with super strong antifouling properties against viscous oil and accelerate the research progress of membrane separation of oil-in-water emulsions.
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高影响因子
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
·
2021
·Vol. 168
·期 2
·022504
·
IF 4.316
Shahid Khan,Chaoyan Fang,Yecheng Ma,Mahmood ul Haq,Mohammad Nisar,Gang Xu,Yong Liu,Gaorong Han
The aim of the study was to determine the effect of inorganic core-shell SiO2 nanoparticles modified with polymethyl methacrylate (PMMA) layer, on the optical and electrochemical properties of poly vinylidenefluoride-co-hexafluoropropylene (PVDF-HFP) gel polymer electrolyte (GPE). The core-shell SiO2 nanoparticles were first modified with PMMA to improve its dispersibility and compatibility in the polymer matrix. The morphology and structural properties of the core-shell SiO2 nanoparticles before and after modification were characterized by XRD, FTIR and SEM analysis. Then the modified SiO2 nanoparticles were used to prepare the composite GPE, composed of chemically modified core-shell structured SiO2-PMMA and PVDF-HFP polymer matrix. The transformation of nano-silica to SiO2-PMMA nanoparticles shows the better compatibility of PMMA and PVDF-HFP that favours the silica to be well dispersed in the organic matrix and significantly improve the doping effect. Various concentrations of modified SiO2-PMMA were used to dope PVDF-HFP GPEs. The results indicate that the 10% doping shows the highest ionic conductivity i.e. 2.22 × 10−3 s cm−1. In addition, the composite GPEs show the high transmittance and good thermal stability; therefore it can add important insight into developing high-performance materials for electrochromic devices.
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Membranes
·
2021
·Vol. 11
·期 11
·803
·
IF 4.106
Qianqian Xu,Yuchao Chen,Tonghu Xiao,Xing Yang
The use of poly(vinylidene fluoride) (PVDF) microfiltration (MF) membranes to purify oily water has received much attention. However, it is challenging to obtain high-performance PVDF microfiltration membranes due to severe surface fouling and rapid decline of permeability. This study explored a new approach to fabricate high-performance PVDF/silica (SiO2) composite membrane via the use of a polymer solution featuring lower critical solution temperature (LCST) characteristics and the non-solvent thermally induced phase separation method (NTIPS). Coupling with morphological observations, the membrane formation kinetics were analyzed in depth to understand the synergistic effect between the LCST solution properties and fabrication conditions in NTIPS. Utilizing such a synergistic effect, the transition from finger-like macrovoid pores to bi-continuous highly connected pores could be flexibly tuned by increasing the PVDF concentration and the weight ratio of SiO2/PVDF in the dope solution and by raising the coagulation temperature to above the LCST of the solution. The filtration experiments with surfactant-stabilized oil-water emulsion showed that the permeation flux of the PVDF/SiO2composite membranes was higher than 318 L·m−2·h−1·bar−1and the rejection above 99.2%. It was also shown that the PVDF/SiO2composite membranes, especially those fabricated above the LCST, demonstrated better hydrophilicity, which resulted in significant enhancement in the anti-fouling properties for oil/water emulsion separation. Compared to the benchmark pure PVDF membrane in oily water purification, the optimal composite membrane T70 was demonstrated via the 3-cycle filtration experiments with a significantly improved flux recovery ratio (Frr) and minimal reduced irreversible fouling (Rir). Overall, with the developed method in this work, facile procedure to tune the membrane morphology and pore structure was demonstrated, resulting in high performance composite membranes suitable for oil/water emulsion separation.Keywords:PVDF/SiO2composite membrane;lower critical solution temperature (LCST);nonsolvent thermally induced phase separation (NTIPS);structural control;oil-in-water emulsion
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ACS Applied Energy Materials
·
2021
·
IF 6.024
Yange Yu,Wenzhu Shao,Jing Zhong,Huijian Ye,Li Yang,Liang Zhen
Ferroelectric poly(vinylidene fluoride) (PVDF)-based polymer nanocomposites have garnered considerable attention for film capacitor applications. However, the addition of highly polarized inorganic fillers with a large proportion into PVDF leads to poor processability and high energy loss, which significantly destroy the structural integrity of the film and restrain the practical application of film capacitors. Herein, we constructed core–shell BaTiO3 (BTO)@graphene oxide (GO) architectures via an aerosolization method and incorporated them into the PVDF matrix, which not only provided a highly insulating GO layer to improve the breakdown strength and suppress the dielectric loss but also improved the dispersion of fillers to realize a high interfacial interaction. The 0.4 wt % BTO@GO/PVDF film exhibited a high discharged energy density of 2.9 J cm–3 at 200 MV m–1, 70% higher than that of the PVDF film, a charge–discharge efficiency of 86%, and a depressed dielectric loss of 0.07 at 1 kHz. Moreover, the ultralow content of fillers can greatly improve the processability and reduce the defects with the structural integrity as well as the performance stability of the film during stretching. This work sheds light on the improvement of energy storage performance of polymer nanocomposites for film capacitors.
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Materials Research Express
·
2020
·Vol. 8
·期 1
·015303
·
IF 1.929
Dashuai Zhang,Xiaoxue Lin,Yan Zhang,Xiaopeng Zhang,Chen Li,Yang Lin,Tianyi Sun,Linhua Zhu,Qiang Lin,Zaifeng Shi
The PVDF/PVC superhydrophobic composite membrane was prepared by non-solvent induced phase separation method. When the concentration of PVDF/PVC(= 85/15) is 4%, DMF can be used as a solvent to prepare PVDF/PVC superhydrophobic composite membrane by using the simple and applicable NIPS method. Through static contact angle and rolling angle, it was found that the maximum contact angle of PVDF/PVC composite membrane with low concentration can reach 152°, rolling angle is 3 degrees, and the surface potential energy is also relatively low about 8°. It was found by DSC that the crystallinity of PVDF/PVC composite membrane with low concentration was higher, SEM shows that the surface of 4% PVDF/PVC composite membrane has nano scale protrusion, and AMF finds that the surface of 4% PVDF/PVC composite membrane was high Surface roughness. When the surface roughness was high, the surface hydrophobicity is improved, the wetting problem was alleviated, the self-cleaning ability of the membrane is improved, and the membrane pollution is reduced. It was found that the 4% PVDF/PVC composite membrane prepared by low concentration method has a long-lasting self-cleaning performance and can be used as an organic coating in the field of self-cleaning.
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危险品化学品经营许可证（带存储）