scholarly journals New insight into the adsorption behaviour of effluent organic matter on organic–inorganic ultrafiltration membranes: a combined QCM-D and AFM study

2018 ◽  
Vol 5 (8) ◽  
pp. 180586 ◽  
Author(s):  
Xudong Wang ◽  
Danxi Huang ◽  
Botao Cheng ◽  
Lei Wang
Keyword(s):  
Organic Matter ◽  
Vinylidene Fluoride ◽  
Adsorption Behaviour ◽  
Effluent Organic Matter ◽  
Hydrophobic Membrane ◽  
Force Microscopy ◽  
Membrane Surfaces ◽  
Initial Stage ◽  
Poly Vinylidene Fluoride ◽  
Repulsive Forces

Adsorption of organic matter on membranes plays a major role in determining the fouling behaviour of membranes. This study investigated effluent organic matter (EfOM) adsorption behaviour onto poly(vinylidene fluoride) (PVDF) membrane blended with SiO 2 nanoparticles using quartz crystal microbalance with dissipation monitoring (QCM-D) and atomic force microscopy (AFM). The QCM-D results suggested that low adsorption of EfOM and an EfOM layer with a non-rigid and open structure was formed on SiO 2 -terminated membrane surfaces. Conformational assessment showed that EfOM undergoes adsorption via two steps: (i) in the initial stage, a rapid adsorption of EfOM accumulated onto the membrane; (ii) the change in dissipation was still occurring when the adsorption frequency reached balance, and the layer tended towards a more rearranged or organized secondary structure upon adsorption onto the more hydrophilic surface. For the AFM force test, when a self-made EfOM-coated probe approached the membrane, a ‘jump-in’ was observed for the hydrophobic membrane after repulsion at a small distance, while only repulsive forces were observed for PVDF/SiO 2 membranes. This study demonstrated that the PVDF/SiO 2 membrane changed the entire filtration process, forming a ‘soft’ open conformation in the foulant layer.

scholarly journals Piezoelectric Response in Hybrid Micropillar Arrays of Poly(Vinylidene Fluoride) and Reduced Graphene Oxide

Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1065 ◽  
Author(s):  
Igor O. Pariy ◽  
Anna A. Ivanova ◽  
Vladimir V. Shvartsman ◽  
Doru C. Lupascu ◽  
Gleb B. Sukhorukov ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Low Temperature ◽  
Reduced Graphene Oxide ◽  
Vinylidene Fluoride ◽  
Piezoelectric Response ◽  
Response Force ◽  
Force Microscopy ◽  
Reduced Graphene ◽  
Poly Vinylidene Fluoride ◽  
Micropillar Arrays

This study was dedicated to the investigation of poly(vinylidene fluoride) (PVDF) micropillar arrays obtained by soft lithography followed by phase inversion at a low temperature. Reduced graphene oxide (rGO) was incorporated into the PVDF as a nucleating filler. The piezoelectric properties of the PVDF-rGO composite micropillars were explored via piezo-response force microscopy (PFM). Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) showed that α, β, and γ phases co-existed in all studied samples, with a predominance of the γ phase. The piezoresponse force microscopy (PFM) data provided the local piezoelectric response of the PVDF micropillars, which exhibited a temperature-induced downward dipole orientation in the pristine PVDF micropillars. The addition of rGO into the PVDF matrix resulted in a change in the preferred polarization direction, and the piezo-response phase angle changed from −120° to 20°–40°. The pristine PVDF and PVDF loaded with 0.1 wt % of rGO after low-temperature quenching were found to possess a piezoelectric response of 86 and 87 pm/V respectively, which are significantly higher than the |d33eff| in the case of imprinted PVDF 64 pm/V. Thus, the addition of rGO significantly affected the domain orientation (polarization) while quenching increased the piezoelectric response.

scholarly journals Morphological, Electrical, and Chemical Characteristics of Poly(sodium 4-styrenesulfonate) Coated PVDF Ultrafiltration Membranes after Plasma Treatment

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1689 ◽  
Author(s):  
Sandoval-Olvera ◽  
González-Muñoz ◽  
Díaz ◽  
Maroto-Valiente ◽  
Ochoa ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Photoelectron Spectroscopy ◽  
Vinylidene Fluoride ◽  
Electrical Impedance Spectroscopy ◽  
Morphological Properties ◽  
X Ray ◽  
Force Microscopy ◽  
Poly Vinylidene Fluoride ◽  
Liquid Displacement ◽  
Positively Charged

A commercial ultrafiltration (UF) membrane (HFM-183 de Koch Membrane Systems) made of poly(vinylidene fluoride) (PVDF), was recovered with a negatively-charged polyelectrolyte (poly(sodium 4-styrenesulfonate)) (PSS), and the effects on its electric, chemical, and morphological properties were analyzed. Atomic force microscopy (AFM), liquid–liquid displacement porometry, Electrical Impedance Spectroscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy were used to investigate the modifications induced by the deposition of PSS on the PVDF positively-charged membrane and after its treatment by a radio frequency Ar-plasma. These techniques confirmed a real deposition and posterior compaction of PSS with increasing roughness and decreasing pore sizes. The evolution of the electric resistances of the membranes confirmed crosslinking and compaction with shielding of the sulfonated groups from PSS. In this way, a membrane with a negatively-charged active layer and a pore size which was 60% lower than the original membrane was obtained. The composition of the additive used by manufacturers to modify PVDF to make it positively charged was obtained by different procedures, all of which depended upon the results of X-ray photoelectron spectroscopy, leading to fairly consistent results. This polymer, carrying positive charges, contains quaternary nitrogen, as confirmed by XPS. Moreover, Raman spectroscopy confirmed that PVDF changes from mostly the to the α phase, which is more stable as a substrate for the deposited PSS. The aim of the tested modifications was to increase the retention of divalent anions without reducing permeability.

scholarly journals Interfacial piezoelectric polarization locking in printable Ti3C2Tx MXene-fluoropolymer composites

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Nick A. Shepelin ◽  
Peter C. Sherrell ◽  
Emmanuel N. Skountzos ◽  
Eirini Goudeli ◽  
Jizhen Zhang ◽  
...  
Keyword(s):  
Electrostatic Interactions ◽  
Vinylidene Fluoride ◽  
Mechanical Energy ◽  
Piezoresponse Force Microscopy ◽  
Low Energy ◽  
Force Microscopy ◽  
Energy Harvesters ◽  
Poly Vinylidene Fluoride ◽  
Dynamics Simulations ◽  
Locking Phenomena

AbstractPiezoelectric fluoropolymers convert mechanical energy to electricity and are ideal for sustainably providing power to electronic devices. To convert mechanical energy, a net polarization must be induced in the fluoropolymer, which is currently achieved via an energy-intensive electrical poling process. Eliminating this process will enable the low-energy production of efficient energy harvesters. Here, by combining molecular dynamics simulations, piezoresponse force microscopy, and electrodynamic measurements, we reveal a hitherto unseen polarization locking phenomena of poly(vinylidene fluoride–co–trifluoroethylene) (PVDF-TrFE) perpendicular to the basal plane of two-dimensional (2D) Ti3C2Tx MXene nanosheets. This polarization locking, driven by strong electrostatic interactions enabled exceptional energy harvesting performance, with a measured piezoelectric charge coefficient, d33, of −52.0 picocoulombs per newton, significantly higher than electrically poled PVDF-TrFE (approximately −38 picocoulombs per newton). This study provides a new fundamental and low-energy input mechanism of poling fluoropolymers, which enables new levels of performance in electromechanical technologies.

scholarly journals Effect of Annealing Temperature on the Morphology and Piezoresponse Characterisation of Poly(vinylidene fluoride-trifluoroethylene) Films via Scanning Probe Microscopy

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
K. Lau ◽  
Y. Liu ◽  
H. Chen ◽  
R. L. Withers
Keyword(s):  
Melting Point ◽  
Annealing Temperature ◽  
Vinylidene Fluoride ◽  
Hysteresis Loops ◽  
Piezoresponse Force Microscopy ◽  
Scanning Probe ◽  
Force Microscopy ◽  
Poly Vinylidene Fluoride ◽  
Probe Microscope ◽  
Small Grains

Poly(vinylidene fluoride-trifluoroethylene) (PVDF-TrFE (70/30)) films were synthesized on a gold/glass substrate via spin coating. The films were annealed at a temperature between125∘Cand180∘C. Nanoscale characterisation of the morphology, polarization switching, and local piezoresponse hysteresis loops of PVDF-TrFE film was studied using a scanning probe microscope (SPM). Ferroelectric switchable domains were identified by piezoresponse force microscopy (PFM) for all films. Small grains, with weak piezoresponse character, were observed for films annealed just above the Curie temperature. Acicular grains were obtained when the annealing temperature approached the melting point and the piezoresponse increased. Annealing above the melting point decreased the piezoresponse and the morphology changed dramatically into plate-like structures.

An approach to durable poly(vinylidene fluoride) thin film loudspeaker

2003 ◽  
Vol 18 (12) ◽  
pp. 2904-2911 ◽  
Author(s):  
C.S. Lee ◽  
J.Y. Kim ◽  
D.E. Lee ◽  
J. Joo ◽  
S. Han ◽  
...  
Keyword(s):  
Thin Film ◽  
Indium Tin Oxide ◽  
Photoelectron Spectroscopy ◽  
Vinylidene Fluoride ◽  
X Ray ◽  
Force Microscopy ◽  
Low Surface Energy ◽  
Oxide Electrodes ◽  
Atomic Force ◽  
Poly Vinylidene Fluoride

The piezoelectric poly(vinylidene fluoride) (PVDF) surface possessing low surface energy was modified by the ion-assisted-reaction (IAR) method for the application of thin film speaker. The IAR-treated hydrophilic PVDF surface was investigated using atomic force microscopy and x-ray photoelectron spectroscopy. The adhesion strength between various types of electrodes and the film was dramatically improved due to the hydrophilic functional groups, such as –C–O–, –(C=O)–, –(C=O)–O–, and so forth. A durable loudspeaker film was fabricated by enhancing the adhesion between the screen-printed poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (PEDOT/PSS) and the modified PVDF films. The PVDF speaker film with the PEDOT/PSS electrode showed higher durability, flatter sound pressure level characteristics, and easier processability compared to metals or indium tin oxide electrodes.

Sign in / Sign up

Export Citation Format

Share Document