Wikipedia:WikiProject Chemicals/Chembox validation/VerifiedDataSandbox and Polyvinylidene fluoride: Difference between pages

{{Short description|Non-reactive thermoplastic fluoropolymer}}

{{Use dmy dates|date=August 2023}}

| Verifiedfields = changed

| Watchedfields = changed

| verifiedrevid = 476994017

| ImageSize = 150px

| IUPACName = Poly(1,1-difluoroethylene) <ref>{{cite web | url=http://www.ebi.ac.uk/chebi/searchId.do;A89DFCA7829681968B0AF2A1DD6CC9E5?chebiId=CHEBI:53250 | title=poly(vinylene fluoride) (CHEBI:53250) | access-date=14 July 2012}}</ref>

| OtherNames = Polyvinylidene difluoride; poly(vinylene fluoride); Kynar; Hylar; Solef; Sygef; poly(1,1-difluoroethane)

| SystematicName =

| PubChem = 6369

| MeSHName = polyvinylidene+fluoride

| ChEBI_Ref = {{ebicite|changed|EBI}}

| ChEBI = 53250

| ChemSpiderID_Ref = {{chemspidercite|changed|chemspider}}

| ChemSpiderID = None

}}

| Formula = −(C₂H₂F₂)_''n''−

| Appearance = Whitish or translucent solid

| Solubility = Insoluble

| MeltingPt = {{convert|177|C|F}}

}}

}}

| OtherCompounds = [[Polyvinyl fluoride|PVF]], [[Polyvinyl chloride|PVC]], [[PTFE]]}}

'''Polyvinylidene fluoride''' or '''polyvinylidene difluoride''' ('''PVDF''') is a highly non-reactive [[thermoplastic]] [[fluoropolymer]] produced by the polymerization of [[1,1-Difluoroethylene|vinylidene difluoride]]. Its chemical formula is (C₂H₂F₂)_''n''.

PVDF is a specialty [[plastic]] used in applications requiring the highest purity, as well as resistance to solvents, acids and hydrocarbons. PVDF has low density 1.78&nbsp;g/cm³ in comparison to other fluoropolymers, like [[polytetrafluoroethylene]].

It is available in the form of piping products, sheet, tubing, films, plate and an insulator for premium wire. It can be injected, molded or welded and is commonly used in the chemical, semiconductor, medical and defense industries, as well as in [[lithium-ion battery|lithium-ion batteries]]. It is also available as a [[cross-link]]ed [[closed-cell foam]], used increasingly in aviation and aerospace applications, and as an exotic 3D printer filament. It can also be used in repeated contact with food products, as it is FDA-compliant and non-toxic below its degradation temperature.<ref>{{Cite web|url=https://www.plasticsintl.com/shop-by-material/pvdf|title = PVDF (Polyvinylidene fluoride, Tecaflon ®, Solef®, Kynar®) &#124; Plastics International}}</ref>

As a fine powder grade, it is an ingredient in high-end paints for metals. These PVDF paints have extremely good [[Gloss paint|gloss]] and color retention. They are in use on many prominent buildings around the world, such as the [[Petronas Towers]] in Malaysia and [[Taipei 101]] in Taiwan, as well as on commercial and residential metal roofing.

PVDF membranes are used in [[western blot]]s for the immobilization of proteins, due to its non-specific affinity for amino acids.

PVDF is also used as a binder component for the carbon electrode in [[supercapacitors]] and for other electrochemical applications.

==Names==

PVDF is sold under a variety of brand names including KF ([[Kureha Chemical Industries|Kureha]]), Hylar ([[Solvay S.A.|Solvay]]), Kynar ([[Arkema]]) and Solef (Solvay).

===Synthesis===

The easiest way of synthesizing PVDF is the [[radical polymerization]] of vinylidene fluoride (VF₂), however, the polymerization is not completely regiospecific. The asymmetric structure of VF₂ leads to the orientation isomers during the polymerization. The configuration of the monomer in the chain can be either "head to head" or "head to tail".

[[image:Ferroelectric-wiki-w1.png|thumb|200px|center|Figure 4: Three orientation isomers of polyvinylidene fluoride]]

To get more control on the regiospecific polymer synthesis, [[copolymerization]] was proposed. One of these methods is introducing the precursor polymer made from copolymerization of VF₂ with either 1-chloro-2,2-difluoroethylene (CVF₂) or 1-bromo-2,2-difluoroethylene( BVF₂). The chlorinated or brominated monomers are attacked at their CF₂ carbon by growing –CH₂CF₂'''∙''' radical. After reductive dechlorination or debromination with tri-n-butyltin hydride they become a reversed VF₂ unit in the final polymer. Therefore, a [[regioisomer]] of PVDF is formed.<ref>{{cite journal | author1 =Cais, R.E.|author2 =Kometani, J.M. | title =Synthesis and two-dimensional NMR of highly aregic poly(vinylidene fluoride) |journal=Macromolecules | year=1985 | volume=18 | pages=1354–1357 | doi=10.1021/ma00148a057 | issue =6|bibcode = 1985MaMol..18.1354C}}</ref>

[[image:Ferroelectric-wiki-w2.png|thumb|200px|center|Figure 5: Scheme of regiospecific polymer synthesis]]

[[image:Ferroelectric-wiki-w3.png|thumb|200px|right|Figure 6: Schematic description of two most common conformations of PVDF, the left one is tg⁺tg⁻ and the right one is all trans, the yellow sphere represents fluorine atom, the white sphere represents hydrogen atom and the grey sphere represents the carbon atom.]]

==Properties==

In 1969, strong [[piezoelectricity]] was observed in PVDF, with the piezoelectric coefficient of [[Piezoelectricity#Mechanism|poled]] (placed under a strong electric field to induce a net dipole moment) thin films as large as 6–7 [[picocoulomb|pC]]/[[Newton (units)|N]]: 10 times larger than that observed in any other [[polymer]].<ref>{{cite journal |doi=10.1143/JJAP.8.975 |title=The Piezoelectricity of Poly (vinylidene Fluoride) |year=1969 |last1=Kawai |first1=Heiji |journal=Japanese Journal of Applied Physics |volume=8 |issue=7 |pages=975–976|bibcode=1969JaJAP...8..975K |s2cid=122316276 }}</ref>

PVDF has a [[glass transition temperature]] (''T''_g) of about −35&nbsp;°[[Celsius|C]] and is typically 50–60% crystalline. To give the material its piezoelectric properties, it is mechanically stretched to orient the molecular chains and then poled under tension. PVDF exists in several phases depending on the chain conformations as trans (T) or gauche (G) linkages: TGTG' for α and δ phase, TTTT for β phases, and TTTGTTTG' for γ and ε phases. The α and ε conformations lack piezoelectric properties because of the antiparallel alignment of dipoles within its unit cell. The β, γ, and δ phases feature a parallel arrangement of dipoles, rendering them polar crystals with a non-zero dipole moment. Among these phases, the β phase stands out due to its remarkable remnant polarization and the highest dipolar moment per unit cell, garnering more interest compared to the others.<ref>{{Cite journal |last=Martins |first=P. |last2=Lopes |first2=A.C. |last3=Lanceros-Mendez |first3=S. |date=April 2014 |title=Electroactive phases of poly(vinylidene fluoride): Determination, processing and applications |url=https://doi.org/10.1016/j.progpolymsci.2013.07.006 |journal=Progress in Polymer Science |volume=39 |issue=4 |pages=683–706 |doi=10.1016/j.progpolymsci.2013.07.006 |issn=0079-6700}}</ref> When poled, PVDF is a [[ferroelectric]] polymer, exhibiting efficient [[piezoelectric]] and [[pyroelectric]] properties.<ref>{{Cite journal |last1=Lolla |first1=Dinesh |last2=Gorse |first2=Joseph |last3=Kisielowski |first3=Christian |last4=Miao |first4=Jiayuan |last5=Taylor |first5=Philip L. |last6=Chase |first6=George G. |last7=Reneker |first7=Darrell H. |date=17 December 2015 |title=Polyvinylidene fluoride molecules in nanofibers, imaged at atomic scale by aberration corrected electron microscopy |journal=Nanoscale |volume=8 |issue=1 |pages=120–128 |doi=10.1039/c5nr01619c |issn=2040-3372 |pmid=26369731|bibcode=2015Nanos...8..120L |s2cid=205976678 |url=http://www.escholarship.org/uc/item/1fp5d847 }}</ref> These characteristics make it useful in [[sensor]] and [[battery (electricity)|battery]] applications. Thin films of PVDF are used in some newer [[thermal camera]] sensors.

Unlike other popular piezoelectric materials, such as [[lead zirconate titanate]] (PZT), PVDF has a negative [[piezoelectric coefficient|d₃₃]] value. Physically, this means that PVDF will compress instead of expand or vice versa when exposed to the same electric field.<ref>{{Cite journal |last1=Lolla |first1=Dinesh |last2=Lolla |first2=Manideep |last3=Abutaleb |first3=Ahmed |last4=Shin |first4=Hyeon U. |last5=Reneker |first5=Darrell H. |last6=Chase |first6=George G. |date=9 August 2016 |title=Fabrication, Polarization of Electrospun Polyvinylidene Fluoride Electret Fibers and Effect on Capturing Nanoscale Solid Aerosols |journal=Materials |volume=9 |issue=8 |page=671 |doi=10.3390/ma9080671|pmid=28773798 |pmc=5510728 |bibcode=2016Mate....9..671L |doi-access=free }}</ref>

=== Thermal ===

PVDF resin has been subjected to high-heat experiments to test its thermal stability. PVDF was held for 10&nbsp;years at 302&nbsp;°F (150&nbsp;°C), and following measurements indicated no thermal or oxidative breakdown occurred {{Citation needed|date=February 2020}}. PVDF resin has been recorded stable up to 707&nbsp;°F (375&nbsp;°C).<ref>{{Cite web |url=https://www.extremematerials-arkema.com/en/product-families/kynar-pvdf-family/physical-and-mechanical-properties/ |title=Physical and Mechanical Properties |website=Arkema, Inc. Innovative Chemistry }}</ref>

=== Chemical compatibility ===

PVDF exhibits an increased chemical resistance and compatibility among thermoplastic materials. PVDF is considered to have excellent / inert resistance to:{{citation needed|date=March 2019}}

* strong acids, weak acids,

* ionic, salt solutions,

* halogenated compounds,

* hydrocarbons,

* aromatic solvents,

* aliphatic solvents,

* oxidants,

* weak bases.

=== Chemical sensitivity ===

PVDF, similar to other [[fluoropolymer]]s, exhibits chemical sensitivity, in general, with the following chemical families:

* strong bases, caustics,

* esters,

* ketones.<ref name=":0">{{Cite web |url=https://pvcpipesupplies.com/media/documents/kynar_specs.pdf |title=PVDF Performance & Characteristics Data |website=Plastic Pipe Solutions }}</ref>

=== Intrinsic properties and resistance ===

Polyvinylidene fluoride expresses inherent resistance characteristics in certain high-focus applications. Namely these are: ozone oxidation reactions, nuclear radiation, UV damage, and microbiological, fungus growth.{{citation needed|date=March 2019}} PVDF's resistance to these conditions is fairly distinctive among [[thermoplastic]] materials. PVDF's carbon and fluoride elemental stability contributes to this resistance, as well as the polymeric integration of PVDF during its processing.{{citation needed|date=March 2019}}

==Processing==

PVDF may be synthesized from the gaseous [[vinylidene fluoride]] (VDF) monomer by a free-radical (or controlled-radical) polymerization process. This may be followed by processes such as melt casting, or processing from a solution (e.g. solution casting, [[spin coating]], and film casting). [[Langmuir–Blodgett film]]s have also been made. In the case of solution-based processing, typical solvents used include [[dimethylformamide]] and the more volatile [[butanone]]. In aqueous [[emulsion polymerization]], the [[fluorosurfactant]] [[perfluorononanoic acid]] is used in [[anion]] form as a processing aid by solubilizing monomers.<ref name=Prevedouros2006>{{cite journal |author=Prevedouros K. |author2=Cousins I. T. |author3=Buck R. C. |author4=Korzeniowski S. H. |title=Sources, fate and transport of perfluorocarboxylates |journal=Environ. Sci. Technol. |volume=40 |issue=1 |pages=32–44 |date=January 2006 |pmid=16433330 |doi=10.1021/es0512475|bibcode=2006EnST...40...32P }}</ref> Compared to other fluoropolymers, it has an easier [[Polymer melt|melt]] process because of its relatively low melting point of around 177&nbsp;°C.

Processed materials are typically in the non-piezoelectric alpha phase. The material must either be stretched or annealed to obtain the piezoelectric beta phase. The exception to this is for PVDF [[thin films]] (thickness in the order of micrometres). Residual stresses between thin films and the substrates on which they are processed are great enough to cause the beta phase to form.

In order to obtain a piezoelectric response, the material must first be poled in a large electric field. Poling of the material typically requires an external field of above 30 megavolts per metre (MV/m). Thick films (typically >100&nbsp;[[micrometre|μm]]) must be heated during the poling process in order to achieve a large piezoelectric response. Thick films are usually heated to 70–100&nbsp;°C during the poling process.

A quantitative defluorination process was described by [[mechanochemistry]],<ref>{{cite journal |doi=10.1002/app.1663 |title=Mechanochemical solid-phase reaction between polyvinylidene fluoride and sodium hydroxide |year=2001 |last1=Zhang |first1=Qiwu |last2=Lu |first2=Jinfeng |last3=Saito |first3=Fumio |last4=Baron |first4=Michel |journal=Journal of Applied Polymer Science |volume=81 |issue=9 |page=2249|url=https://hal.archives-ouvertes.fr/hal-01845792/file/Mechanochemical-Solid-Phase-Reaction-between-Polyvinylidene-Fluoride-and-Sodium-Hydroxide.pdf }}</ref> for safe eco-friendly PVDF waste processing.

==Applications==

[[File:A UPW Installation using PVDF Piping.png|thumb|right|PVDF piping used to carry [[ultrapure water]]]]

PVDF is a thermoplastic that expresses versatility for applications similar to other thermoplastics, particularly fluoropolymers. PVDF resin is heated and handled for use in extrusion and injection molding to produce [[Plastic pipework#PVDF (polyvinylidene difluoride)|PVDF pipes]], sheets, coatings, films, and molded PVDF products, such as bulk containers. Common industry applications for PVDF thermoplastics include:<ref name=":0" />

* chemical processing,

* electricity, batteries and electronic components,

* construction and architecture,

* healthcare and pharmaceutics,

* biomedical research,

* ultra-pure applications,

* nuclear waste handling,

* petrochemical, oil and gas,

* food, beverage processing,

* water, wastewater management.

=== In electronics / electricity ===

PVDF is commonly used as insulation on electrical wires, because of its combination of flexibility, low weight, low thermal conductivity, high chemical corrosion resistance, and heat resistance. Most of the narrow 30-gauge wire used in [[wire wrap]] circuit assembly and [[printed circuit board]] rework is PVDF-insulated. In this use the wire is generally referred to as "Kynar wire", from the trade name.

The piezoelectric properties of PVDF are exploited in the manufacture of [[tactile sensor#Tactile sensor arrays|tactile sensor arrays]], inexpensive [[strain gauges]], and lightweight audio [[transducer]]s. Piezoelectric panels made of PVDF are used on the Venetia Burney Student Dust Counter, a scientific instrument of the [[New Horizons]] space probe that measures dust density in the [[outer Solar System]].<ref>{{cite journal |last1=Horanyi |first1=Mihaly |title=First results from the Venetia Burney Student Dust Counter on the New Horizons mission |url=https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2010GL043300 |journal=Geophysical Research Letters |date=2010 |volume=37 |issue=11 |doi=10.1029/2010GL043300 |s2cid=129795884 |access-date=17 August 2023|doi-access=free }}</ref>

PVDF is the standard binder material used in the production of composite electrodes for lithium-ion batteries.<ref>{{Cite journal|last1=Ordoñez|first1=J.|last2=Gago|first2=E. J.|last3=Girard|first3=A.|date=1 July 2016|title=Processes and technologies for the recycling and recovery of spent lithium-ion batteries|journal=Renewable and Sustainable Energy Reviews|volume=60|pages=195–205|doi=10.1016/j.rser.2015.12.363|issn=1364-0321|url=https://hal.archives-ouvertes.fr/hal-02557122/file/Ordonez2016.pdf }}</ref> Solution of PVDF {{nobr|1−2%}} by mass in [[Methylpyrrolidone|''N''-methyl-2-pyrrolidone]] (NMP) is mixed with an active lithium storage material such as graphite, silicon, tin, LiCoO₂, LiMn₂O₄, or LiFePO₄ and a conductive additive such as [[carbon black]] or [[carbon nanofiber]]s. This slurry is cast onto a metallic current collector, and the NMP is evaporated to form a composite or [[paste electrode]]. PVDF is used because it is chemically inert over the potential range used and does not react with the electrolyte or lithium.

=== In biomedical science ===

In the biomedical sciences, PVDF is used in [[immunoblotting]] as an [[artificial membrane]] (usually with 0.22 or 0.45-micrometre pore sizes), on which proteins are transferred using electricity (see [[western blotting]]). PVDF is resistant to solvents and, therefore, these membranes can be easily stripped and reused to look at other proteins. PVDF membranes may be used in other biomedical applications as part of a membrane filtration device, often in the form of a syringe filter or wheel filter. The various properties of this material, such as heat resistance, resistance to chemical corrosion, and low protein binding properties, make this material valuable in the biomedical sciences for preparation of medications as a sterilizing filter, and as a filter to prepare samples for analytical techniques such as [[high-performance liquid chromatography]] (HPLC), where small amounts of particulate matter can damage sensitive and expensive equipment.

PVDF transducers have the advantage of being dynamically more suitable for [[modal testing]] than semiconductor [[piezoresistive transducer]]s and more compliant for structural integration than [[piezoceramic transducer]]s. For those reasons, the use of PVDF active sensors is a keystone for the development of future structural-health monitoring methods, due to their low cost and compliance.<ref name=Guzman>{{cite journal |doi=10.1088/0964-1726/22/6/065020 |title=Survivability of integrated PVDF film sensors to accelerated ageing conditions in aeronautical/aerospace structures |year=2013 |last1=Guzman |first1=E. |last2=Cugnoni |first2=J. |last3=Gmür |first3=T. |journal=Smart Mater. Struct. |volume=22 |issue=6 |page=065020|bibcode=2013SMaS...22f5020G |s2cid=136758382 }}</ref>

=== In high-temperature processes ===

PVDF is used as piping, sheet, and internal coatings in high-temperature, hot acid, radiation environment applications due to PVDF's resistance characteristics and upper temperature thresholds. As piping, PVDF is rated up to 248&nbsp;°F (120&nbsp;°C). Examples of PVDF uses include nuclear reactor waste handling, chemical synthesis and production, ([[sulfuric acid]], common), air plenums, and boiler service pipe.

=== Other uses ===

PVDF is used for specialty [[monofilament fishing line]]s, sold as fluorocarbon replacements for nylon monofilament. The surface is harder, so it is more resistant to abrasion and sharp fish teeth. Its [[refractive index]] is lower than nylon, which makes the line less discernible to sharp fish eyes. It is also denser than nylon, making it sink faster towards fish.<ref>[http://www.seaguar.com/about-seaguar/seaguar-history-01.htm Seaguar history]&nbsp;— Kureha America, Inc. manufacturer's site. {{webarchive|url=https://web.archive.org/web/20100620214019/http://www.seaguar.com/about-seaguar/seaguar-history-01.htm |date=20 June 2010 }}</ref>

==Other forms==

===Copolymers===

The copolymer Poly(vinylidene fluoride-co-hexafluoropropylene) or PVDF-HFP is used as a co-polymer in the blades of [[artificial turf]].<ref>{{cite news |last1=McMenemy |first1=Jeff |title=Portsmouth to test for PFAS in new turf field. Is it dangerous? City says no. Others disagree. |url=https://www.seacoastonline.com/story/news/local/2021/12/10/portsmouth-nh-test-pfas-turf-field-amid-disagreement-danger/6447547001/ |access-date=30 December 2021 |work=Portsmouth Herald |date=10 December 2021}}</ref>

Copolymers of PVDF are also used in piezoelectric and [[electrostriction|electrostrictive]] applications. One of the most commonly used copolymers is P(VDF-[[trifluoroethylene]]), usually available in ratios of about 50:50 and 65:35 by mass (equivalent to about 56:44 and 70:30 molar fractions). Another one is P(VDF-[[tetrafluoroethylene]]). They improve the piezoelectric response by improving the crystallinity of the material.

While the copolymers' unit structures are less polar than that of pure PVDF, the copolymers typically have a much higher crystallinity. This results in a larger piezoelectric response: d₃₃ values for P(VDF-TFE) have been recorded to be as high as −38 [[pico-|p]] [[Coulomb|C]]/N<ref>{{cite journal |doi=10.1063/1.364300 |title=Temperature dependence of elastic, dielectric, and piezoelectric properties of "single crystalline" films of vinylidene fluoride trifluoroethylene copolymer |year=1997 |last1=Omote |first1=Kenji |last2=Ohigashi |first2=Hiroji |last3=Koga |first3=Keiko |journal=Journal of Applied Physics |volume=81 |issue=6 |page=2760|bibcode=1997JAP....81.2760O }}</ref> compared to −33 pC/N in pure PVDF.<ref>{{cite journal |doi=10.1080/00150198608245016 |title=The measurement of the shear piezoelectric coefficients of polyvinylidene fluoride |year=1986 |last1=Nix |first1=E. L. |last2=Ward |first2=I. M. |journal=Ferroelectrics |volume=67 |issue=1 |pages=137–141|bibcode=1986Fer....67..137N }}</ref>

===Terpolymers===

[[Terpolymer]]s of PVDF are the most promising one in terms of electromechanically induced strain. The most commonly used PVDF-based terpolymers are P(VDF-TrFE-CTFE) and P(VDF-TrFE-CFE).<ref>{{cite journal | title = Ferroelectric and electromechanical properties of poly(vinylidene-fluoride–trifluoroethylene–chlorotrifluoroethylene) terpolymer | first1 = Haisheng | last1 = Xu | first2 = Z.-Y. | last2 = Cheng | first3 = Dana | last3 = Olson | first4 = T. | last4 = Mai | first5 = Q. M. | last5 = Zhang | first6 = G. | last6 = Kavarnos | pages = 2360–2362 | journal = Applied Physics Letters | volume = 78 | issue = 16 | date = 16 April 2001 | doi = 10.1063/1.1358847 | publisher = AIP Publishing LLC, American Institute of Physics| bibcode = 2001ApPhL..78.2360X }}</ref><ref>{{cite journal | title = Phase Transitions and Ferroelectric Relaxor Behavior in P(VDF−TrFE−CFE) Terpolymers | first1 = Hui-Min | last1 = Bao | first2 = Jiao-Fan | last2 = Song | first3 = Juan | last3 = Zhang | first4 = Qun-Dong | last4 = Shen | first5 = Chang-Zheng | last5 = Yang | first6 = Q. M. | last6 = Zhang | journal = Macromolecules | date = 3 April 2007 | volume = 40 | issue = 7 | pages = 2371–2379 | doi = 10.1021/ma062800l | publisher = ACS Publications| bibcode = 2007MaMol..40.2371B }}</ref> This [[relaxor]]-based [[ferroelectric]] terpolymer is produced by random incorporation of the bulky third monomer ([[chlorotrifluoroethylene]], CTFE) into the polymer chain of P(VDF-TrFE) copolymer (which is ferroelectric in nature). This random incorporation of CTFE in P(VDF-TrFE) copolymer disrupts the long-range ordering of the ferroelectric polar phase, resulting in the formation of nano-polar domains. When an electric field is applied, the disordered nano-polar domains change their conformation to all-[[Cis-trans isomerism|trans]] conformation, which leads to large electrostrictive strain and a high room-temperature [[dielectric constant]] of ~50.<ref>{{cite book | first1 = Saad | last1 = Ahmed | first2 = Erika | last2 = Arrojado | first3 = Nirmal | last3 = Sigamani | first4 = Zoubeida | last4 = Ounaies | title = Behavior and Mechanics of Multifunctional Materials and Composites 2015 | chapter = Electric field responsive origami structures using electrostriction-based active materials | author4-link=Zoubeida Ounaies | editor-first = Nakhiah C. | editor-last = Goulbourne | date = 14 May 2015 | isbn = 978-1-62841-535-3 | volume = 9432 |page = 943206| publisher = Society of Photographic Instrumentation Engineers (SPIE) | doi = 10.1117/12.2084785 | bibcode = 2015SPIE.9432E..06A | s2cid = 120322803}}</ref>

== Safety and regulations ==

PVDF is widely considered safe and ubiquitous used for water treatment,<ref name="WDR2023">{{cite journal | last=Pankratz | first=Tom | title=All PFAS are not created Equal | journal=Water Desalination Report | volume=59 | issue=14 | date=2023-04-17 | issn= | doi=| page=1}}</ref> the food industry, and biocompatible devices like hernia meshes or internal devices. PVDF differs from PFAS in that alternating groups are hydrogen, making it less resilient to high temperatures, but also meaning that byproducts don't degrade into known hazardous PFAS.<ref name="b829">{{cite journal | last=Rabuni | first=Mohamad Fairus | title=The contrastive study of chemical treatment on the properties of hydrophobic PVDF membrane | journal=Journal of Applied Science & Process Engineering | volume=2 | issue=1 | date=1970-01-01 | issn=2289-7771 | doi=10.33736/jaspe.163.2015 | page=}}</ref> However, studies examining ecotoxity have shown that very high concentrations (up to 100 mg/L) may alter jellyfish behavior, while not being toxic to them.<ref name="k121">{{cite journal | last=Di Giannantonio | first=Michela | last2=Gambardella | first2=Chiara | last3=Miroglio | first3=Roberta | last4=Costa | first4=Elisa | last5=Sbrana | first5=Francesca | last6=Smerieri | first6=Marco | last7=Carraro | first7=Giovanni | last8=Utzeri | first8=Roberto | last9=Faimali | first9=Marco | last10=Garaventa | first10=Francesca | title=Ecotoxicity of Polyvinylidene Difluoride (PVDF) and Polylactic Acid (PLA) Microplastics in Marine Zooplankton | journal=Toxics | publisher=MDPI AG | volume=10 | issue=8 | date=2022-08-17 | issn=2305-6304 | doi=10.3390/toxics10080479 | doi-access=free | page=479| pmc=9416274 }}</ref> In the US, FDA regulations consider PVDF to be food safe,<ref name="q803">{{cite web | title=Code of Federal Regulations Title 21 | website=accessdata.fda.gov | date=2023-12-22 | url=https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=177.2510 | access-date=2024-06-22}}</ref> while US EPA water treatment regulations on PFAS have avoided placing limits on PVDF, while strictly limit concentrations of PFAS.<ref name="l421">{{cite web | title=Interim Guidance on the Destruction and Disposal of Perfluoroalkyl and Polyfluoroalkyl Substances and Materials Containing Perfluoroalkyl and Polyfluoroalkyl Substances—Version 2 (2024) | website=EPA | url=https://www.epa.gov/system/files/documents/2024-04/2024-interim-guidance-on-pfas-destruction-and-disposal.pdf | access-date=2024-06-22}}</ref> However, proposed regulations in the EU aim to ban "any substance that contains at least one fully fluorinated methyl (CF3) or methylene (CF2-) carbon atom (without any H/Cl/Br/I attached to it)”.<ref name="EPAPFAS">{{cite web | title=Registry of restriction intentions until outcome | website=ECHA | url=https://echa.europa.eu/registry-of-restriction-intentions/-/dislist/details/0b0236e18663449b#:~:text=Per%2D%20and%20polyfluoroalkyl%20substances%20(PFAS)&text=Per%2D%20and%20polyfluoroalkyl%20substances%20(PFASs,%2FI%20attached%20to%20it). | access-date=2024-06-22}}</ref> Unless exemptions are made, the application of inconsistent and severe regulations may propose an existential risk to the industry.<ref name="WDR2024">{{cite journal | last=Pankratz | first=Tom | title=PVDF membranes’ uncertain future | journal=Water Desalination Report | volume=60 | issue=23 | date=2024-06-17 | issn= | doi=| page=1}}</ref>

==See also==

* [[Ferroelectric polymers]]

* [[Ferroelectricity]]

* [[Pyroelectricity]]

==References==

{{reflist}}

[[Category:Biomaterials]]

[[Category:Ferroelectric materials]]

[[Category:Fluoropolymers]]

[[Category:Piezoelectric materials]]

[[Category:Thermoplastics]]