Tunable acoustic metasurface based on PVDF/PI unimorph sheets

2021 ◽  
Author(s):  
Xin Li ◽  
Yang Zhou ◽  
Zhang-Zhao Yang ◽  
Xin-Ye Zou ◽  
Jian-chun Cheng
Keyword(s):  
Acoustic Waves ◽  
Polyvinylidene Fluoride ◽  
Composite Sheet ◽  
Pvdf Membrane

Abstract We propose a tunable metasurface unit based on a composite sheet of polyvinylidene fluoride (PVDF) membrane and polyimide tape. The deformation of the sheet can be adjusted by applying a voltage to the PVDF membrane, and the phase of reflected acoustic waves can be continuously tuned and spans the full 2π range. Various acoustic functions can be achieved by applying different voltages on the units. The experiment is also given to prove the unit’s ability to control acoustic waves. Our design shows the possibility of dynamically manipulating acoustic waves and designing integrated acoustic devices by piezo-membrane micromechanical system.

Hydrocarbon degradation and separation of bilge water via a novel TiO2-HNTs/PVDF-based photocatalytic membrane reactor (PMR)

RSC Advances ◽  
2015 ◽  
Vol 5 (19) ◽  
pp. 14147-14155 ◽  
Author(s):  
A. Moslehyani ◽  
A. F. Ismail ◽  
M. H. D. Othman ◽  
T. Matsuura
Keyword(s):  
Titanium Dioxide ◽  
Polyvinylidene Fluoride ◽  
Membrane Reactor ◽  
Halloysite Nanotubes ◽  
Hydrocarbon Degradation ◽  
Pvdf Membrane ◽  
Bilge Water ◽  
Flat Sheet ◽  
Photocatalytic Membrane Reactor

This paper focuses on the potential of a novel flat sheet nanocomposite titanium dioxide (TiO2)-halloysite nanotubes (HNTs)/polyvinylidene fluoride (PVDF) membrane as a photocatalytic separator in the photocatalytic membrane reactor (PMR).

scholarly journals Characterization of the Initial Fouling Layer on the Membrane Surface in a Membrane Bioreactor: Effects of Permeation Drag

Membranes ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 121
Author(s):  
Shengli Wang ◽  
Xin Lu ◽  
Lanhe Zhang ◽  
Jingbo Guo ◽  
Haifeng Zhang
Keyword(s):  
Zeta Potential ◽  
Electron Donor ◽  
Energy Barrier ◽  
Polyvinylidene Fluoride ◽  
Membrane Bioreactor ◽  
Membrane Surface ◽  
Permeate Flux ◽  
Pvdf Membrane ◽  
Operating Modes

In this study, the properties of the initial fouling layer on the membrane surface of a bioreactor were investigated under different operating modes (with or without permeate flux) to improve the understanding of the effect of permeation drag on the formation of the initial fouling layer. It was found that protein was the major component in the two types of initial fouling layers, and that the permeation drag enhanced the tryptophan protein-like substances. The attraction of the initial foulants to the polyvinylidene fluoride (PVDF) membrane was ascribed to the high zeta potential and electron donor component (γ−) of the membrane. Thermodynamic analyses showed that the permeation drag-induced fouling layer possessed high hydrophobicity and low γ−. Due to permeation drag, a portion of the foulants overcame an energy barrier before they contacted the membrane surface, which itself possessed a higher fouling propensity. A declining trend of the cohesive strength among the foulants was found with the increasing development of both fouling layers.

Preparation and Characterization of Hydrophilic PVDF Membrane via Graft Modification by Maleic Anhydride

2011 ◽  
Vol 295-297 ◽  
pp. 286-291
Author(s):  
Li Guo Wang ◽  
Xiao Guang Zhang ◽  
Shu Fang Hou ◽  
Xiu Ju Wang ◽  
Ai Min Wang ◽  
...  
Keyword(s):  
Maleic Anhydride ◽  
Polyvinylidene Fluoride ◽  
Pure Water ◽  
Water Flux ◽  
Pvdf Membrane ◽  
Technical Parameters ◽  
Pure Water Flux ◽  
Flat Membranes ◽  
Better Than

Hydrophilic polyvinylidene fluoride (PVDF) flat ultrafiltration membranes were prepared by wet-spinning method. The effects of technical parameters of maleic anhydride grafted onto PVDF on the performance of hydrophilic PVDF membranes were investigated, the preparation technical parameters were determined, and the hydrophilic PVDF flat membranes were prepared. Then, hydrophilic PVDF membranes were characterized in terms of pure water flux, contact angle, infrared spectroscopic analysis and scanning electron microscope(SEM). The results showed that maleic anhydride had been grafted onto PVDF, and the hydrophilic performance of the modified membrane was better than the traditional one.

Influence of the physicochemical environment on membrane-protein binding: investigation using a fabricated PVDF membrane

2015 ◽  
Vol 35 (4) ◽  
pp. 339-347
Author(s):  
Abdul L. Ahmad ◽  
Norhidayah Ideris ◽  
Ooi Boon Seng ◽  
Low Siew Chun ◽  
Asma Ismail
Keyword(s):  
Membrane Protein ◽  
Protein Binding ◽  
Polyvinylidene Fluoride ◽  
Pvdf Membrane ◽  
Ph Values ◽  
Symmetric Structure ◽  
Binding Mechanisms

Abstract The correlation between the behavior of a polyvinylidene fluoride (PVDF) membrane toward protein binding at different physicochemical environments was investigated. The PVDF membrane was first fabricated and characterized to understand its morphological, polymorph and intrinsic characteristics. The results confirmed that the membrane had a microporous, symmetric structure and high hydrophobicity and electronegativity. The membrane was further tested under different physicochemical environments by modifying the type of protein and pH medium used. The results showed that different proteins and pH values contribute to different membrane-protein binding mechanisms. Overall, the results of PVDF membrane-protein binding were satisfactory and demonstrated the ability of the membrane to capture various proteins or reagents.

Micelle-enhanced Ultrafiltration of Chemical Pretreated Crude Canola Oil Miscella

2012 ◽  
Vol 8 (2) ◽  
Author(s):  
Razieh Niazmand ◽  
Reza Farhoosh ◽  
Seyed Mohammad Ali Razavi ◽  
Seyed Mahmoud Mousavi
Keyword(s):  
Canola Oil ◽  
Carbonyl Compounds ◽  
Polyvinylidene Fluoride ◽  
Oil Oxidation ◽  
Chemical Pretreatment ◽  
Pvdf Membrane ◽  
Chemical Agents ◽  
Micellar Enhanced Ultrafiltration ◽  
Flat Membrane ◽  
Membrane Cell

In the present work, the chemical pretreatment as well as micellar-enhanced ultrafiltration for refining canola oil miscella was investigated. The research has been conducted on adding chemical agents (CaCl2, EDTA and SDS aqueous solutions) to canola oil miscella before ultrafiltration through polyvinylidene fluoride (PVDF) membrane with molecular weight cut-offs (MWCO) 100kDa and 50kDa in a magnetically stirred flat membrane cell. Results showed that SDS solution lowered phospholipids content almost completely. The reduction of phenolic compounds in SDS- and EDTA-pretreated filtered oil was more noticeable than in the processed miscella. On the contrary, the reduction of FFAs was more in the miscella filtered without any chemical agents. The membrane exhibited no appreciable affinity towards tocopherols and carbonyl compounds in the oil samples. SDS and EDTA played an important role in oil oxidation, so that they led to increase in peroxide value.

scholarly journals The influences of polydopamine immersion time on characteristics and performance of polyvinylidene fluoride ultrafiltration membrane

2018 ◽  
Vol 197 ◽  
pp. 09007
Author(s):  
Syawaliah Syawaliah ◽  
Nasrul Arahman ◽  
Medyan Riza ◽  
Sri Mulyati
Keyword(s):  
Polyvinylidene Fluoride ◽  
Water Flux ◽  
Sem Analysis ◽  
Inversion Method ◽  
Asymmetric Structure ◽  
Pvdf Membrane ◽  
Before And After ◽  
Poly Ethylene ◽  
And Performance ◽  
Phase Inversion Method

The Polyvinylidene Fluoride (PVDF) membrane has been prepared by phase inversion method using N,N-dimethylacetamide (DMAc) as solvent and Poly Ethylene Glycol (PEG) as additive. The fabricated membrane was modified by Polydopamine (PDA) coating in concentration of 0.5 mg/ml and immersion times of 2 hours, 6 hours, and 24 hours. The characteristics and performance of the PVDF membranes before and after the modification are studied in this paper. The result of the water flux experiment showed that the PDA-coated PVDF membranes showcased a higher flux than that of pure PVDF membrane. Scanning Electron Microscopy (SEM) analysis confirmed that the membrane had an asymmetric structure consisting of two layers. There was no significant influence on the addition of PDA to the morphology of the pore matrix because the modification was done by surface coating. Fourier Transform Infrared Spectroscopy (FTIR) analysis showed that PDA was successfully introduced on the surface of PVDF membrane with the appearance of O-H from cathecol and N-H peaks at wavenumber range of 3300-3600 cm-1. Modification with PDA increased the mechanical strength of the membrane which affirmed by the results of the tensile and elongation at break evaluation.

scholarly journals Synthesis, characterization and filtration performance of the polyvinylidene fluoride membrane modified by poly(methyl ethacrylate-co-2-acrylamido-2-methylpropane sulfonic acid)

2018 ◽  
Vol 19 (4) ◽  
pp. 1279-1285
Author(s):  
Q. Y. Zhang ◽  
Q. An ◽  
Y. G. Guo ◽  
J. Zhang ◽  
K. Y. Zhao
Keyword(s):  
Sulfonic Acid ◽  
Polyvinylidene Fluoride ◽  
Phase Inversion ◽  
Pure Water ◽  
Water Flux ◽  
Contact Angles ◽  
Fouling Resistance ◽  
Inversion Process ◽  
Pvdf Membrane ◽  
Pure Water Flux

Abstract To enhance the anti-fouling and separating properties of polyvinylidene fluoride (PVDF) membranes, an amphiphilic copolymer of methyl methacrylate and 2-acrylamido-2-methylpropane sulfonic acid, poly(MMA-co-AMPS), was designed and synthesized. Through a phase-inversion process, the poly(MMA-co-AMPS) were fully dispersed in the PVDF membrane. The properties of membrane including the surface and cross-section morphology, surface wettability and fouling resistance under different pH solutions were investigated. Compared to the unmodified PVDF membranes, the contact angles of modified PVDF membranes decreased from 80.6° to 71.6°, and the pure water flux increased from 54 to 71 L·m−2·h−1. In addition, the hybrid PVDF membrane containing 0.5 wt% copolymers demonstrated an larger permeability, better fouling resistance and higher recovery ratio via pure water backlashing, when it was compared with the other blend membranes, and the virgin one in the cyclic test of anti-fouling. The modified membranes with the copolymers possessed an outstanding performance and may be used for further water treatment applications.

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