查找使用阿拉丁产品的科研文献

Microsphere-Fiber Interpenetrated Superhydrophobic PVDF Microporous Membranes with Improved Waterproof and Breathable Performance

Gaoshuo Jiang,Liqiang Luo,Lu Tan,Jinliang Wang,Shenxiang Zhang,Feng Zhang,Jian Jin

Superhydrophobic membranes with extreme liquid water repellency property are good candidates for waterproof and breathable application. Different from the mostly used strategies through either mixing or postmodifying base membranes with perfluorinated compounds, we report in this work a facile methodology to fabricate superhydrophobic microporous membranes made up of pure poly(vinylidene fluoride) (PVDF) via a high-humidity induced electrospinning process. The superhydrophobic property of the PVDF microporous membrane is contributed by its special microsphere-fiber interpenetrated rough structure. The effective pore size and porosity of the PVDF membranes could be well tuned by simply adjusting the PVDF concentrations in polymer solutions. The membrane with optimized superhydrophobicity and porous structure exhibits improved waterproof and breathable performance with hydrostatic pressure up to 62 kPa, water vapor transmission rate (WVT rate) of 10.6 kg m–2 d–1, and simultaneously outstanding windproof performance with air permeability up to 1.3 mm s–1. Our work represents a rather simple and perfluorinated-free strategy for fabricating superhydrophobic microporous membranes, which matches well with the environmentally friendly requirement from the viewpoint of practical application.

Hydrophilic modification of PVDF microfiltration membranes by adsorption of facial amphiphile cholic acid

Meng-Xin Hu,Ji-Nian Li,Shi-Lin Zhang,Liang Li,Zhi-Kang Xu

Amphiphilic molecules have been widely used in surface modification of polymeric materials. Bile acids are natural biological compounds and possess special facial amphiphilic structure with a unusual distribution of hydrophobic and hydrophilic regions. Based on the facial amphiphilicity, cholic acid (CA), one of the bile acids, was utilized for the hydrophilic modification of poly(vinylidene fluoride) (PVDF) microfiltration membranes via the hydrophobic interactions between the hydrophobic face of CA and the membrane surfaces. Ethanol, methanol, and water were respectively used as solvent during CA adsorption procedure. Their polarity affects the CA adsorption amount, as similar to CA concentration and adsorption time. There are no changes on the membrane surface morphology after CA adsorption. The hydrophilicity of PVDF membranes is greatly enhanced and the water drops permeates into the CA modified membranes quickly after modification. All these factors benefit to the permeation flux of membrane for water. When CA concentration is higher than 0.088   M, the water permeation flux is doubled as compared with the nascent PVDF membrane and shows a good stability during filtration procedure. These results reveal the promising potential of facial amphiphilic bile acids for the surface modification of polymeric materials.

Gradient CNT/PVDF piezoelectric composite with enhanced force-electric coupling for soccer training

Zeng Wanghong,Deng Weili,Yang Tao,Wang Shenglong,Sun Yue,Zhang Jieling,Ren Xiarong,Jin Long,Tang Lihua,Yang Weiqing

Real-time monitoring of ball–shoe interactions can provide essential information for high-quality instruction in personalized soccer training, yet existing monitoring systems struggle to reflect specific forces, loci, and durations of action. Here, we design a self-powered piezoelectric sensor constructed by the gradient carbon nanotube/polyvinylidene fluoride (CNT/PVDF) composite to monitor the interactions between the ball and the shoe. Two-dimensional Raman mapping demonstrates the gradient structure of CNT/PVDF prepared by programmable electrospinning combined with a hot pressing. Benefitting from the synergistic effect of local polarization caused by the enrichment of CNT and the reduced diffusion of silver patterns in gradient structure, the as-prepared composite exhibits enhanced force-electric coupling with an excellent sensitivity of 80 mV/N and durability over 15,000 cycles. On this basis, we conformally attach a 3 × 3 sensor array to a soccer shoe, enabling real-time acquisition of kick position and contact force, which could provide quantitative assessment and personalize guidance for the training of soccer players. This self-powered piezoelectric sensor network system offers a promising paradigm for wearable monitoring under strong impact forces.

A Broadband High-Output Acoustoelectric Transducer Based on Electrospun BTO/PVDF-HFP Nanofiber

Weixu Tian,Junyun Zhang,Yue Yu,Zhihua Wen,Jinjin Song,Di Pan,Dawei Li,Jing Li,Sunhee Lee,Jingye Jin,Chenhong Lang

The efficient conversion of ambient acoustic energy into electrical power has attracted considerable research interest for its potential to sustainably power microelectronics and self-powered sensors. Nevertheless, the development of an acoustoelectric transducer that simultaneously delivers broadband response, high conversion efficiency, and substantial power output remains a pressing challenge. Herein, we report a broadband high-output acoustoelectric transducer. The device architecture features an electrospun barium titanate (BTO)/poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) nanofiber membrane, sandwiched between two gold-coated poly(ethylene terephthalate) electrodes with a precisely engineered air spacer. Upon acoustic wave excitation, the membrane and electrode exhibit contact-separation motion, simultaneously exciting both piezoelectric and triboelectric effects. The optimized device, comprising a 0.5 mm air spacer and a 3% BTO-doped PVDF-HFP nanofiber membrane, achieves a peak output of 410.28 V and 50.24 μA under 115 dB acoustic excitation at 170 Hz. The instantaneous maximum power density reaches 11576.12 μW/cm3 (the peak surface power density is 845.06 μW/cm2). The electrical energy generated can directly power miniature electronic devices without additional energy supplying equipment. This structure effectively converts acoustic waves into an electric signal from 1 to 5000 Hz (including infrasound). Therefore, the device holds potential for detecting and warning against natural disasters associated with infrasound emissions. This acoustoelectric transducer thus exhibits promising application prospects in noise energy recovery, environmental monitoring, self-powered systems, speech recognition, and human-computer interaction.

Optimization of Energy Storage Performance in Sandwich-Structured PVDF-NBT/BN Composite Films

Haoran Chen,Jincong Zhang,Tingwei Mei,Tian Zhang,Yong Zhang

With the continuous advancement of modern electronics and power equipment, there is a growing demand for film capacitors with higher dielectric constants and discharge energy densities. In this study, we fabricated a sandwich-structured thin film using polyvinylidene fluoride (PVDF)-bismuth sodium titanate (NBT) as the outer layers and boron nitride (BN) nanosheets as the intermediate layer. The PVDF-NBT layers enhance the material's polarization strength and dielectric constant, while the BN layer ensures its breakdown strength and insulation properties. With an optimal composition of 6 wt % BN and 3 wt % NBT, the composite film achieves an energy storage density of 13.2 J cm−3 and a breakdown strength of 5000 kV/cm while maintaining a low dielectric loss of approximately 0.02 at 1000 Hz. These results indicate that the proposed composite structure holds great promise for applications in dielectric energy storage.

Construction of Superhydrophobic Surfaces Enhanced by Silanized-CNC-Assisted PVDF/PDMS Microsphere Coating

Coatings based on polyvinylidene fluoride (PVDF) and poly(dimethylsiloxane) (PDMS)-based polymeric microspheres can be easily fabricated via non-solvent-induced phase separation (NIPS) and electrostatic spraying (ES) techniques. Both techniques are promising strategies for constructing superhydrophobic surfaces on various substrates. However, PVDF and PDMS inherently suffer from severe aggregation, which generates oversized particles and inhomogeneous microstructures. Conventionally, costly and environmentally hazardous dispersants are required to alleviate this issue, severely restricting the industrial scalability and practical application of such coatings. In this work, methyltrimethoxysilane-modified cellulose nanocrystals (Si-CNCs) were introduced as a green multifunctional modifier to tackle these issues. The results revealed that as structural building blocks and dispersants, Si-CNCs inhibited polymer aggregation via electrostatic repulsion and steric hindrance, refined the particle size and formed uniform micro/nano hierarchical structures. Increasing Si-CNC loading further improved polymer dispersion and superhydrophobic performance. Coatings fabricated by ES showed better hydrophobicity than those fabricated by NIPS. ES achieved a water contact angle (WCA) of 160–166° and a sliding angle (SA) near 1° on cotton fabric, while NIPS had a WCA of 153.8–158° and an SA of around 2°. Wood and glass substrates also obtained favorable superhydrophobicity, with WCAs above 150° and SAs below 1°. Furthermore, all modified surfaces exhibited excellent abrasion resistance. This work provides a relatively eco-friendly, environmentally sustainable, scalable and substrate-flexible strategy for fabricating high-performance PVDF/PDMS-based superhydrophobic coatings.

Self-Cleaning PVDF ultrafiltration membranes via elctro-responsive g-C3N4/rGO composite incorporation

Mengru Wang,Biao Zhang,Wen-Sheng Zou,Jinhui Zhang,Yaqin Wang

A self-cleaning ultrafiltration membrane with electrically switchable antifouling and antibacterial functions was developed by incorporating a g‑C 3 N 4 /reduced graphene oxide (rGO) composite into a polyvinylidene fluoride (PVDF) matrix. At + 1.5  V, the optimized membrane (M3, 7.5  wt% g‑C 3 N 4 ) achieved a pure water flux of 115.97  L·m −2 ·h −1 , and a BSA flux retention 85.6 % (51.35  L·m −2 ·h −1 ) after 3  h, outperforming the control membrane (M0) with 76.57  L·m −2 ·h −1 , and 59.2 % retention (35.53  L·m −2 ·h −1 ). The M3 membrane achieved a BSA rejection of 99.70 %, a flux recovery ratio (FRR) of 93.86 %, and an antibacterial efficiency of ∼99.7 % against E. coli under dark conditions. The superior self-cleaning performance is attributed to the synergistic effects of enhanced electrostatic repulsion and electrocatalytic generation of reactive oxygen species (ROS). This work offers a practical strategy for designing smart separation membranes with on-demand antifouling and self-cleaning capabilities for advanced water purification.

Comparison analysis of combustion performance and mechanism of Al/PVDF and Al/PTFE

Xinyue Fei,Jiang Liu,Yunlan Sun,Minggao Xu,Baozhong Zhu

Although both aluminum/polyvinylidene fluoride (Al/PVDF) and aluminum/polytetrafluoroethylene (Al/PTFE) systems exhibit excellent combustion performance, the study on comparing their combustion behaviors and the underlying mechanisms responsible for their differences are still relatively limited. Therefore, the advantages and disadvantages of the Al/PVDF and Al/PTFE systems were compared through ignition experiments and molecular dynamics simulations. The Al/PTFE system exhibits higher combustion intensity, and the characteristic is attributed to the higher fluorine (F) content in PTFE, which triggers more Al-F reactions. In contrast, the Al/PVDF system exhibits a lower ignition delay time and higher combustion heat, which is attributed to the relatively lower initial decomposition temperature, the higher hydrogen (H) content, and the higher combustion heat in PVDF. Compared to oxygen (O) atoms, H atoms can penetrate the oxide film on the surface of Al particles more rapidly and react with the inner Al atoms, thereby reducing the temperature required for Al atoms to break through the oxide film and participate in reactions.

Highly reliable and decoupled temperature-pressure bimodal sensor based on PVDF-HFP ionogel

Yumei Lin,Ya-Hsin Pai,Shoubo Li,Chao Wang,Jincheng Liao,Fan Wu,Zhen Xu,Qingfeng Song,Yi Feng,Ziqi Liang,Lidong Chen,Shengqiang Bai

Existing bimodal sensors rely on complex multimaterial integration and system topologies, hindering healthcare diagnostics. This work presents a sensor using single-material PVDF-HFP ionogel with a sandwich structure, enabling simultaneous, accurate temperature, and pressure monitoring. Decoupled sensing is achieved via two distinct mechanisms within one material: the ionic thermodiffusion (Soret) effect for temperature and interfacial electrical double-layer (EDL) capacitance for pressure. The sensor exhibits high performance: a temperature sensitivity of 4.2 mV K −1 (limit of detection, LOD: 0.05 K) with < 10 s response time, and pressure sensitivity of 1.35 kPa −1 (LOD: 11 Pa) with < 60 ms response time. Optimized processing yields high-reliability ionogels; unencapsulated samples maintained 93% thermopower after three months of air storage. Finally, sensor arrays integrated into a glove successfully distinguished and mapped pressure and temperature stimuli, demonstrating feasibility for wearable electronics.

Ester Bond-Anchored TMP Moieties for Durable and Rechargeable Anti-biofouling PVDF Membranes

Yang Hao,Shi Feifan,Li Yihang,Shen Rujing,Wei Wei,Wei Ang

Global water scarcity and pollution have elevated membrane separation to an indispensable technology for sustainable water purification. Poly(vinylidene fluoride) (PVDF), prized for its exceptional chemical and mechanical stability, faces a long-standing performance trade-off, as its inherent hydrophobicity causes severe biofouling, while chlorine regeneration for biofilm removal degrades surface-grafted antibacterial functional layers. Herein, we report a high-performance chlorine-rechargeable N-halamine antibacterial membrane (denoted as PPVDF-O-TP-Cl, a PEG-blended PVDF grafted with chlorinated TMP moieties) fabricated via an integrated “passive defense-active attack” strategy, featuring covalent surface anchoring of sterically hindered 2,2,6,6-tetramethylpiperidine (TMP-OH) onto PVDF backbones through ester linkages. The membrane achieved robust broad-spectrum antibacterial efficacy, delivering a 6.1-log reduction against Gram-negative E. coli and a 5.5-log reduction against Gram-positive S. aureus within 30 min, a flux recovery ratio exceeding 90.0%, and retained over 99% antibacterial activity after 10 chlorination-regeneration cycles. Notably, TMP’s bulky methyl groups sterically shield vulnerable ester bonds from hydrolytic and oxidative degradation, while PEG hydration layers and N-halamine moieties synergistically mitigate the interfacial kinetic imbalance plaguing traditional membranes. This work provides a versatile strategy for designing durable rechargeable anti-biofouling membranes, with future investigations warranted into their long-term performance in complex real wastewater matrices and scalable fabrication.

Elastic PVDF-HFP-Based Aerogel for Efficient Passive Radiative Cooling and Thermal Insulation

Kong Yong,Lai Zhengbo,Dai Xiaolei,Xu Fuhao,Shen Xiaodong

Polymer-based aerogels exhibit high thermal management performance including insulation and passive radiative cooling. However, the lack of elasticity limits their application. Herein, we developed an elastic poly(vinylidene fluoride- co -hexafluoropropylene) (PVDF-HFP)-based aerogel (PFHS) for efficient thermal management. PFHS achieves a low thermal conductivity of 0.035 W/(m·K), a high solar reflectance of 98.18%, and a mid-infrared emissivity of 96.85%, as well as high hydrophobicity with a water contact angle of 140 ° . PFHS exhibits a high temperature reduction of 9.8 ° C and an outdoor daytime cooling power of 116.68 W/m 2 under an average solar irradiance of 821.14 W/m 2 . It also has superior thermal insulation performance under cold (−20 ° C) and hot (60 ° C) conditions. Moreover, PFHS has excellent weather resistance and thermal stability. These attributes establish PFHS as a promising prospect for the efficient thermal and environmental management of buildings and outdoor facilities, offering a new strategy for the development of multifunctional polymer aerogels.

Electrospun PVDF microfiltration membrane with enhanced piezoelectric demulsification for efficient oil-water separation

Jingyu Yu,Yingchao Du,Baoliang Chen,Juanjuan Chen,Xiaoying Zhu

Underwater superhydrophilic-oleophobic membranes have been widely regarded as an effective solution for oil-water separation, but their passive antifouling strategies relying on surface modification have long been limited by insufficient interfacial stability and frequent cleaning interruptions during continuous operation. In this study, we developed a piezoelectric composite membrane that integrated demulsification and active antifouling functions. The β -phase content of PVDF nanofibers was regulated by MXene nanosheets, and the highest β -phase content corresponded to the maximum yield of ·OH radicals. Subsequently, FeOOH nanorods were further grown on the fiber surface to construct and stabilize the underwater superhydrophilic-oleophobic interface. During pulsed filtration, piezoelectric activation induced reactive radical generation, which promoted emulsion destabilization and helped mitigate membrane fouling. This design synergistically coupled demulsification with piezoelectric self-cleaning, thereby effectively mitigating irreversible oil fouling. The resulting membrane achieved an oil removal efficiency of 99.5% and maintained a stable permeance of 1057 L·m −2 ·h −1 ·bar −1 during oil-water separation. This work provides a feasible route to mitigate irreversible organic fouling in oil–water separation membranes by integrating demulsification functionality, offering a scalable strategy for the development of piezoelectric active antifouling membranes.