Structural organization of ionic liquids embedded in fluorinated polymers

Ionic liquid based Fluoropolymer solid electrolytes for Lithium-ion batteries

Lightweight polymer composites have drawn a lot of interest because of their improved mechanical, electrical, and thermal properties, which make them perfect for cutting-edge engineering applications. This work reports the synthesis of hybrid polymer composites by integrating multi-walled carbon nanotubes (MWCNTs) into a polyvinylidene fluoride (PVDF) matrix. The synergistic effect of MWCNTs and graphite nanoparticles was explored to achieve improved structural and functional performance. The composites were synthesised using a solution casting method to ensure dispersion of the fillers within the polymer matrix. The fabricated composite was characterized using XRD, FTIR, EDS and FESEM to evaluate its structural, compositional, morphological and elemental properties. XRD confirmed the nanofillers' crystalline phases and structural integrity within the polymer matrix. FTIR spectroscopy identified the characteristic functional groups, verifying interactions between PVDF and the incorporated nanofillers. FESEM images revealed a fibrous CNT network blended within the PVDF polymer matrix and distinct graphite flakes, ensuring uniform dispersion and adhesion. EDS confirmed the elemental composition, highlighting the presence of carbon and fluorine as primary constituents. These combined techniques provide comprehensive insight into the composite's composition, structure and potential functional properties for advanced applications.

PVDF/BaTiO3 films with nanocellulose impregnation: Investigation of structural, morphological and mechanical properties

전자 기기의 빠른 발전에 따른 무선 기기들의 사용은 급격히 늘어나고 있다. 그래서 이런 제품에 자가 발전이 가능한 재료를 적용시키는 사례가 점차 늘고 있다. 여기에 사용되는 재료로서 poly(vinylidene fluoride)(PVDF)가 있는데 PVDF는 piezoelectricity를 낼 수 있는 특별한 결정구조인 β-phase를 가지고 있다. 이 논문에서는 piezoelectricity에 결정적인 영향인 β-phase 함량을 증가시키기 위해 다층 PVDF 필름을 제조하였다. 이 PVDF 필름은 용매인 DMAc에 10%로 용해시킨 것으로 spin rate는 850 rpm, spin time은 60초이며 건조온도는 60 ℃이다. 비교적으로 다층 필름은 단일 층보다 더 높은 β-phase함량을 나타내었다. 이 β-phase함량은 4-layer 필름이 되기까지 점차 증가되었으며 최대 함량은 7.72이다.

This study explores the dielectric properties and conductivity of nanocomposite membranes fabricated using polyvinylidene fluoride (PVDF), multi-walled carbon nanotubes (MWCNTs), and poly (styrene sulfonic acid) (PSSA). PVDF works as a polymer, while PSSA behaves as a polyelectrolyte. With such materials incorporated together, the total dielectric content of the membrane will be added, and it will be suitable for use in the storage of energy and sensors. PVDF is selected as the polymer matrix because of the mechanical strength, flexibility, and inherent dielectric properties of the PVDF material. Developing conductive pathways within the matrix will improve the nanocomposite's electrical conductivity, dielectric constant, and dielectric loss behavior. Due to better system compatibility, MWCNTs are treated with PSSA to enhance the dispersion state and the PVDF matrix's dielectric stability. Characterization based on dielectric measurements was performed with the sample using an impedance analyzer.

The similar molecular structure but different geometries of the carbon nanotube (CNT) and graphene nanoribbon (GNR) create a genuine opportunity to assess the impact of nanofiller geometry (tube vs. ribbon) on the electromagnetic interference (EMI) shielding of polymer nanocomposites. In this regard, GNR and its parent CNT were melt mixed with a polyvinylidene fluoride (PVDF) matrix using a miniature melt mixer at various nanofiller loadings, i.e., 0.3, 0.5, 1.0 and 2.0 wt%, and then compression molded. Molecular simulations showed that CNT would have a better interaction with the PVDF matrix in any configuration. Rheological results validated that CNTs feature a far stronger network (mechanical interlocking) than GNRs. Despite lower powder conductivity and a comparable dispersion state, it was interestingly observed that CNT nanocomposites indicated a highly superior electrical conductivity and EMI shielding at higher nanofiller loadings. For instance, at 2.0 wt%, CNT/PVDF nanocomposites showed an electrical conductivity of 0.77 S·m−1 and an EMI shielding effectiveness of 11.60 dB, which are eight orders of magnitude and twofold higher than their GNR counterparts, respectively. This observation was attributed to their superior conductive network formation and the interlocking ability of the tubular nanostructure to the ribbon-like nanostructure, verified by molecular simulations and rheological assays.

Synchronous removal and separation of multiple contaminants by poly (vinylidene fluoride)/polyaniline ultrafiltration membrane

Functionalized BaTiO3 enhances piezoelectric effect towards cell response of bone scaffold

ABSTRACTTo optimize the proton transport performance of polyvinylidene fluoride (PVdF), a proton exchange membrane (PEM) material, carbon nanotube (CNT), and zirconium hydrogen phosphate (ZrP) have been blended into the PVdF matrix. Adopting a hydrothermal synthesis route, the acidic ZrP can be better conjugated with the positively charged CNT functionalized by cetyltrimethylammonium bromide (CTAB). As visualized using electroscopes, ZrP nanocrystallines are intimately dotted and homogeneously distributed on CNT. The ZrP–PVdF interaction can be attributed to hydrogen bonding between hydroxyl and F‐terminal groups. By incorporating well CNT/ZrP into PVdF via solution casting, the pore architecture can be regulated; namely, the macro‐voids in PVdF are greatly reduced. The composite membranes exhibit tensile stress of 48–52 MPa while sustaining the thermal stability of PVdF. The incorporated CNT/ZrP can suppress void porosity and enhance film hydrophilicity. With improved wettability, the methanol permeability can be reduced to less than 2 × 10−9 cm2∙s−1, ca. one‐sixth that of pure PVdF. The proton conductivity for PVdF‐CNT0.03‐ZrP0.06, with CNT and ZrP mass content respectively 3 and 6 wt% that of PVdF, attains 0.089 S·cm−1 at 100°C, showing upgraded conducting capability. The membrane selectivity can be remarkably enhanced, verifying that CNT/ZrP blending is a facile and profitable approach for PEM optimization.

The Chemical vapor deposition (CVD) graphene/ BaTiO 3 (BT)/polyvinylidene fluoride (PVDF) nanocomposites were prepared by powder metallurgy. SEM results show that CVD GS and BT are well dispersed within the PVDF matrix. Compared with binary CVD graphene sheets (GS)/PVDF and BT/PVDF nanocomposites, the dielectric properties of the CVD GS/BT/PVDF nanocomposites exhibit a better dielectric performance. The powder metallurgic method is an effective way to fabricate multiple components composites and avoid serious inhomogeneity and aggregation of fillers in the polymer matrix.

The main electrophysical properties of polyvinylidene fluoride (PVDF) films produced by two technologies: the solution casting method and the method of hot pressing from the melt are investigated. To analyze the PVDF films, methods of dielectric spectroscopy (DS), IR spectroscopy, TGA/DSC analysis, and x-ray diffraction (XRD) are used. It is demonstrated that the IR spectra of both PVDF films change weakly in comparison with the virgin PVDF film. The absorption bands characteristic for α-, β-, and γ-phases are observed for the virgin and both types of PVDF films. This testifies to the fact that the molecular structure of film samples is practically independent of their processing method. The only difference is that the new absorption band at 1723 cm–1 arises in the IR spectra of the films produced by the method of hot pressing from the melt. The TGA/DSC analysis demonstrates that the beginning melting temperature, melting temperature, beginning decomposition temperature, and decomposition temperature for the film samples produced by the method of hot pressing from the melt decrease by 8, 2, 10, and 12°C, respectively, compared to the film samples produced by the solution casting method.

Soft actuators are increasingly being required for a variety of application ranging from robotics to biomedicine. This work reports on the development of printable materials for soft actuator applications based on ionic liquids (ILs) and a fluorinated polymer, poly(vinylidene fluoride) (PVDF). ILs sharing the same cation 1‑butyl‑3-methylimidazolium, [Bmim]+ and different anions (tricyanomethanide, [C(CN3)]−, dicyanamide, [N(CN2)]− and thiocyanate, [SCN]−) were incorporated into the PVDF polymer matrix at 40% wt. and processed by direct writing printing technique.Rheological measurements of the IL/PVDF solutions allowed to stablish a correlation between shear stress and viscosity, being observed a shear thinning behavior. Independently of the IL anion, the inclusion ILs leads to variations in the sample morphology related to the formation of significantly smaller spherulites than in PVDF with well-defined borders and an increase of the electroactive β phase content and crystallinity degree of the polymer. The incorporation of the ILs into the PVDF matrix induces a mechanical plasticizing effect. A maximum ionic conductivity of 5.2 × 10−5 S/cm has been achieved for the [Bmim][N(CN2)]/PVDF composite. The potential of the developed printable materials as soft actuators has been experimentally demonstrated and theoretically evaluated, the highest displacement of 1.0 mm at an applied voltage of 4 Vpp being obtained for [Bmim][SCN]/PVDF. Finally, the implementation of an all printed micro gripper shows the potential of the materials for applications.

An increasing trend in creating materials with a greater extent of sustainability from an ecological and financial perspective involves usage of bio resources and industrial residues. In this paper, leftover bamboo micro particles (BMP) from bamboo factories were collected and used as fillers with polyvinylidene fluoride (PVDF) matrix in varying concentrations (1, 3, 5, 7, and 9 wt.%) to fabricate low‐cost composite films using solvent casting route for mechanical energy harvesting purpose. Out of the prepared samples, PVDF with 5 wt.% BMP showed maximum electroactive phase content (82%), tensile strength (34.23 MPa), and piezoelectric voltage (6.5 V) among the untreated samples. PVDF with 5 wt.% BMP is then subjected to NaOH treatment for further enhancement in overall performance. PVDF with 5 wt.% treated BMP also showed 467% increment in output voltage and 235% increment in output current as compared to pure PVDF. The piezoelectric output voltage of PVDF with 5 wt.% treated BMP is then measured under impact loading conditions to determine its suitability as an impact sensor. A bamboo‐based piezoelectric impact sensor that is highly sensitive and cost‐effective opens enormous possibilities for sustainability and circular economies.

이 연구에서는 터널 시공 시 터널 배수관으로 유입되는 미세입자의 흐름과 이에 의한 물리/화학적 폐색현상에 따른 터널배수재의 성능저하를 PVDF film의 진동을 이용하여 성능을 향상시키는 방법의 적용 가능성에 대해 실내실험을 통하여 고찰하였다. 연구에서 터널로 유입되는 미세입자 슬러리 유입의 터널 환경을 모사하여 진행하였고 PVDF film을 이용한 기초 실험과 배수재를 모사한 모형실험으로 나누어 수행하였다. 기초 실험에서는 PVDF film에 50% 함수비(민물과 바닷물)의 점토를 흘려 주파수별 점토 슬러리의 흐름특성에 대한 효율성을 고찰하였으며 배수재 모사 실험에서는 배수관에 부직포를 부착시켜 슬러리의 흐름과 막힘 현상 해소에 대한 진동 효과를 고찰하였다. 실험결과는 진동에 의한 배수재의 배수성능, 즉 슬러리의 흐름과 막힘 해소현상이 아주 높게 나타났다. 이상의 실험결과를 종합하여 배수관을 기존 배수재와 융합, 응용, 활용할 수 있는 하이브리드 배수시스템을 개발할 수 있는 기초 자료를 확립하였다. 【This study investigated the possible use of vibration from polyvinylidene fluoride(PVDF) film to enhance the performance of the deteriorated tunnel drainage due to physical/chemical clogging of the fine particles through a series of laboratory experiments. The test program was consisted of two different experiments, fundamental investigation and drainage model test. In the fundamental investigation, flow of clay slurry mixed with 50% water (freshwater and brine) on PVDF film with various frequencies was examined. In the model tests, slurry clogging to the woven fiber attached to drainage pipe and its reduction by vibration was investigated. Results of the experiment show that vibration from PVDF film enhances the drain performance significantly. Based upon the investigation, it gives an essential data that are needed for a potential use of hybrid drainage system with PVDF.】

In order to enhance the hydrophobicity of polyvinylidene fluoride (PVDF) porous membranes, the blending of PVDF with a hydrophobic ionic liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim][PF6]) was carried out. The modified PVDF membranes with [Bmim][PF6] were fabricated through a non-solvent induced phase inversion using lithium chloride as a porogen in the PVDF casting solution. The effects of [Bmim][PF6] on the membrane characteristics were investigated. FT-IR analysis indicates that the IL is successfully retained by the PVDF membrane. Thermogravimetric analysis reveals that the optimum temperature of the modified membrane is below 300°C. Scanning electron microscopy pictures show that modified membranes have more homogeneous and larger diameter pores with a mean pore size of 0.521 µm and porosity of 78 %. By measuring the IL leaching during the membrane fabrication, it was found that the modified membrane does not lose IL. Atomic force microscopy shows that the roughness of the modified membrane surface increases slightly, but the contact angle of the modified membrane increases significantly from 88.1° to 110.1°. The reason for this is that the fluorine-containing IL has a low surface energy, which can enhance the hydrophobicity of the membrane. Finally, by comparing modified membranes with different IL concentrations, we draw a conclusion that the modified membrane with an IL concentration of 3 wt-% has the best properties of pore size, porosity, and hydrophobicity.