نتایج جستجو برای: pvdf

تعداد نتایج: 2314  

2017
Stephen Ducharme Chun-gang Duan Wai-Ning Mei Jaewu Choi Peter A. Dowben W. N. Mei J. R. Hardy S. Ducharme P. A. Dowben

– The electronic structure and band symmetries of the ferroelectric phase of poly (vinylidene fluoride) (PVDF) are studied by using the first-principles density-functional method. Our calculated results agree well with the angle-resolved photoemission experiments. We find that the PVDF crystal has an energy gap of about 6 eV at the Γ-point. Large dispersion of the valence band is found only alo...

Journal: :Journal of Molecular Liquids 2022

Hybrid materials based on ionic liquids (ILs) and polymers are increasingly being used for the development of smart multifunctional materials, allowing to tune polymer properties or introduce new ones. Nonetheless, structural organization ILs within matrix is not properly understood. This work reports different incorporated into polyvinylidene fluoride (PVDF) films. The effect IL type ([Pmim][T...

Journal: :Advanced Functional Materials 2023

Additively manufactured flexible and high-performance piezoelectric devices are highly desirable for sensing energy harvesting of 3D conformal structures. Herein, the study reports a significantly enhanced piezoelectricity in polyvinylidene fluoride (PVDF) achieved through situ dipole alignment PVDF within PVDF-2D molybdenum disulfide (2D MoS2) composite by printing. The shear stress-induced po...

Journal: :Materials Science Poland 2022

Abstract In this work, a synthesis to improve surface wetting resistance composites via infusion of graphene (G) structure into the polyvinylidene fluoride (PVDF) matrices is introduced. Graphene incorporated PVDF matrix with percentage 1.0 wt.% up 2.5 using simple solvent blending and dry-casting methods. The morphological structural properties infused are investigated variety characterization...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه فردوسی مشهد - دانشکده مهندسی 1393

هدف این مطالعه ساخت و تعیین مشخصات غشا اولترافیلتراسیون نانوکامپوزیت pvdf/pvc/f-mwcntsمی باشد. غشاهای خالص pvdf و pvc و غشاهای ترکیبی pvdf/pvc ساخته شدند و باروش های مرسوم مانند sem، زاویهی تماس، تخلخل، متوسط اندازه ی حفرات وآزمون کشش تعیین مشخصات شدند. عملکرد غشاهای ساخته شده با انجام تست شار آب خالص، شار محلول دکستران و درصد دفع دکستران در یک واحد آزمایشگاهی جداسازی غشایی مورد ارزیابی قرارگرف...

2004
Haibin Su William A. Goddard

We used first principles methods to study static and dynamical mechanical properties of the ferroelectric polymer poly(vinylidene fluoride) (PVDF) and its copolymer with trifluoro ethylene (TrFE). We use density functional theory [within the generalized gradient approximation (DFT-GGA)] to calculate structure and energetics for various crystalline phases for PVDF and P(VDF-TrFE). We find that t...

2012
Steven J. Hinder Chris Lowe John F. Watts

The outermost nanometres of a poly(vinylidene difluoride) (PVdF) based coil coating have been investigated using X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). A reference PVdF based coating formulation and three variations of this formulation were characterised by XPS. The addition of flow agent and/or acrylic co-polymers induced significa...

پایان نامه :دانشگاه بین المللی امام خمینی (ره) - قزوین - دانشکده فنی 1392

با توجه به اینکه کامپوزیت های زمینه پلیمری با الگوی اتصال 3-0 قابلیت ارتجاع دارند و برای ساخت نمونه های پیچیده مطلوب هستند، این الگو موضوع بسیاری از پژوهش ها در زمینه مواد پیزوالکتریک قرار گرفته است. هدف از انجام این پژوهش ساخت فیلم کامپوزیت های pzt-pvdf با الکوی اتصال 3-0 و بررسی تاثیر نسبت حجمی و اندازه دانه pzt و همچنین بررسی تاثیر پارامترهای فرایند ساخت بر خواص آن ها بوده است. بدین منظور ا...

Journal: :journal of nanostructures 2012
a. akbari a. yunessnia lehi

poly(vinylidene fluoride) (pvdf) fibers with two molecular weights were prepared via electrospinning process. in this process, the concentration of spinning depended drastically on the gelation process. also, it was experimentally smaller than obtained concentration in the solution entanglement number approach (sena). proof of this incompatibility was explained by the properties of pvdf and its...

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