Structural Characterization and Physicochemical Properties of Functionally Porous Proton-Exchange Membrane Based on PVDF-SPA Graft Copolymers.

Fluorinated proton-exchange membranes (PEMs) based on graft copolymers of dehydrofluorinated polyvinylidene fluoride (D-PVDF), 3-sulfopropyl acrylate (SPA), and 1H, 1H, 2H-perfluoro-1-hexene (PFH) were prepared via free radical copolymerization and characterized for fuel cell application. The membrane morphology and physical properties were studied via small-(SAXS) and wide-angle X-ray scattering (WAXS), SEM, and DSC. It was found that the crystallinity degree is 17% for PEM-RCF (co-polymer with SPA) and 16% for PEM-RCF-2 (copolymer with SPA and PFH). The designed membranes possess crystallite grains of 5-6 nm in diameter. SEM images reveal a structure with open pores on the surface of diameters from 20 to 140 nm. Their transport and electrochemical characterization shows that the lowest membrane area resistance (0.9 Ωcm2) is comparable to perfluorosulfonic acid PEMs (such as Nafion®) and polyvinylidene fluoride (PVDF) based CJMC cation-exchange membranes (ChemJoy Polymer Materials, China). Key transport and physicochemical properties of new and commercial membranes were compared. The PEM-RCF permeability to NaCl diffusion is rather high, which is due to a relatively low concentration of fixed sulfonate groups. Voltammetry confers that the electrochemical behavior of new PEM correlates to that of commercial cation-exchange membranes, while the ionic conductivity reveals an impact of the extended pores, as in track-etched membranes.

Synthesis of Calamitic Fluorinated Mesogens with Complex Crystallization Behavior.

This work presents the synthesis and self-organization of the calamitic fluorinated mesogen, 1,1,2,2-tetrafluoro-2-(1,1,2,2-tetrafluoro-4-iodobutoxy)ethanesulfonic acid, a potential model for perfluorosulfonic acid membranes (PFSA). The compound is derived in three steps from 1,1,2,2-tetrafluoro-2-(1,1,2,2-tetrafluoro-2-iodoethoxy)ethanesulfonyl fluoride, achieving a 78% overall yield. The resulting compound exhibits intricate thermal behavior. At 150 °C, a crystal-to-crystal transition is observed due to the partial disordering of calamitic molecules, which is followed by isotropization at 218 °C. Upon cooling, sample ordering occurs through the formation of large smectic liquid crystalline phase domains. This thermotropic state transforms into a layered crystal phase at lower temperatures, characterized by alternating hydrophilic and hydrophobic layers. Using X-ray diffraction, crystalline unit cell models at both room temperature and 170 °C were proposed. Computer simulations of the molecule across varying temperatures support the idea that thermal transitions correlate with a loss of molecular orientation. Importantly, the study underscores the pivotal role of precursor self-organization in aligning channels during membrane fabrication, ensuring controlled and oriented positioning.

Fluoropolymers as Unique and Irreplaceable Materials: Challenges and Future Trends in These Specific Per or Poly-Fluoroalkyl Substances.

In contrast to some low-molar-mass per- and polyfluoroalkyl substances (PFASs), which are well established to be toxic, persistent, bioaccumulative, and mobile, fluoropolymers (FPs) are water-insoluble, safe, bioinert, and durable. These niche high-performance polymers fulfil the 13 polymer-of-low-concern (PLC) criteria in their recommended conditions of use. In addition, more recent innovations (e.g., the use of non-fluorinated surfactants in aqueous radical (co)polymerization of fluoroalkenes) from industrial manufacturers of FPs are highlighted. This review also aims to show how these specialty polymers endowed with outstanding properties are essential (even irreplaceable, since hydrocarbon polymer alternatives used in similar conditions fail) for our daily life (electronics, energy, optics, internet of things, transportation, etc.) and constitute a special family separate from other "conventional" C1-C10 PFASs found everywhere on Earth and its oceans. Furthermore, some information reports on their recycling (e.g., the unzipping depolymerization of polytetrafluoroethylene, PTFE, into TFE), end-of-life FPs, and their risk assessment, circular economy, and regulations. Various studies are devoted to environments involving FPs, though they present a niche volume (with a yearly production of 330,300 t) compared to all plastics (with 460 million t). Complementary to other reviews on PFASs, which lack of such above data, this review presents both fundamental and applied strategies as evidenced by major FP producers.

Fluoropolymer Nanoparticles Synthesized via Reversible-Deactivation Radical Polymerizations and Their Applications.

Fluorinated polymeric nanoparticles (FPNPs) combine unique properties of fluorocarbon and polymeric nanoparticles, which has stimulated massive interest for decades. However, fluoropolymers are not readily available from nature, resulting in synthetic developments to obtain FPNPs via free radical polymerizations. Recently, while increasing cutting-edge directions demand tailored FPNPs, such materials have been difficult to access via conventional approaches. Reversible-deactivation radical polymerizations (RDRPs) are powerful methods to afford well-defined polymers. Researchers have applied RDRPs to the fabrication of FPNPs, enabling the construction of particles with improved complexity in terms of structure, composition, morphology, and functionality. Related examples can be classified into three categories. First, well-defined fluoropolymers synthesized via RDRPs have been utilized as precursors to form FPNPs through self-folding and solution self-assembly. Second, thermally and photoinitiated RDRPs have been explored to realize in situ preparations of FPNPs with varied morphologies via polymerization-induced self-assembly and cross-linking copolymerization. Third, grafting from inorganic nanoparticles has been investigated based on RDRPs. Importantly, those advancements have promoted studies toward promising applications, including magnetic resonance imaging, biomedical delivery, energy storage, adsorption of perfluorinated alkyl substances, photosensitizers, and so on. This Review should present useful knowledge to researchers in polymer science and nanomaterials and inspire innovative ideas for the synthesis and applications of FPNPs.

Altering the bio-inert properties of surfaces by fluorinated copolymers of mPEGMA.

Hydrophilic materials display "bio-inert properties", meaning that they are less recognized as foreign substances by proteins and cells. Such materials are often water soluble; therefore, one general approach to enable the use of these materials in various applications deals with copolymerizing hydrophilic monomers with hydrophobic ones to facilitate such resulting copolymers water insoluble. However, reducing the hydrophilic monomer amount may reduce the bio-inert properties of the material. The decrease in bio-inert properties can be avoided when small amounts of fluorine are used in copolymers with hydrophilic monomers, as presented in this article. Even in small quantities (7.9 wt%), the fluorinated monomer, 1,1,1,3,3,3-hexafluoropropan-2-yl 2-fluoroacrylate (FAHFiP), contributed to the improved hydrophobicity of the polymers of the long side-chain poly(ethylene glycol) methyl ether methacrylate (mPEGMA) bearing nine ethylene glycol units turning them water insoluble. As evidenced by the AFM deformation image, a phase separation between the FAHFiP and mPEGMA domains was observed. The copolymer with the highest amount of the fluorinated monomer (66.2 wt%) displayed also high (82 %) FAHFiP amount at the polymer-water interface. In contrast, the hydrated sample with the lowest FAHFiP/highest mPEGMA amount was enriched of three times more hydrophilic domains at the polymer-water interface compared to that of the sample with the highest FAHFiP content. Thus, by adding a small FAHFiP amount to mPEGMA copolymers, water insoluble in the bulk too, could be turned highly hydrophilic at the water interface. The high content of intermediate water contributed to their excellent bio-inert properties. Platelet adhesion and fibrinogen adsorption on their surfaces were even more decreased as compared to those on poly(2-methoxyethyl acrylate), which is typically used in medical devices.

Synthesis and Characterization of Core-Double-Shell-Structured PVDF-grafted-BaTiO3/P(VDF-co-HFP) Nanocomposite Films.

Core-double-shell-structured nanocomposite films consisting of polyvinylidene fluoride-grafted-barium titanate (PVDF-g-BT) incorporated into a P(VDF-co-hexafluoropropylene (HFP)) copolymer matrix were produced via a solution mixing method for energy storage applications. The resulting films were thoroughly investigated via spectroscopic, thermal, and morphological analyses. Thermogravimetric data provided an enhancement of the thermal stability, while differential scanning calorimetry indicated an increase in the crystallinity of the films after the addition of PVDF-g-BT. Moreover, broadband dielectric spectroscopy revealed three dielectric processes, namely, glass-rubber relaxation (αa), relaxation associated with the polymer crystalline phase (αc), and slower relaxation in the nanocomposites resulting from the accumulation of charge on the interface between the PVDF-g-BT filler and the P(VDF-co-HFP) matrix. The dependence of the dielectric constant from the composition was analyzed, and we found that the highest permittivity enhancement was obtained by the highest concentration filler added to the largest concentration of P(VDF-co-HFP). Mechanical analysis revealed an improvement in Young's modulus for all nanocomposites versus pristine P(VDF-co-HFP), confirming the uniformity of the distribution of the PVDF-g-BT nanocomposite with a strong interaction with the copolymer matrix, as also evidenced via scanning electron microscopy. The suggested system is promising for use in high-energy-density storage devices as supercapacitors.

Recycling and the end of life assessment of fluoropolymers: recent developments, challenges and future trends.

Herein, we present the state of the art technology on the recycling, reuse, thermal decomposition (by thermolysis, thermal processing, flash pyrolysis, smoldering, open burning, open-air detonation, and incineration), and the life cycle assessment of fluoropolymers (FPs, ranging from poly(tetrafluoroethylene), PTFE, and poly(vinylidene fluoride), PVDF, to various fluorinated copolymers based on VDF and TFE). FPs are niche specialty polymers endowed with exceptional properties and have found many applications in high-tech industries. However, compared to other polymers, the reuse of FPs is still not well-established and is in its infancy. Accordingly, their recycling has attracted increasing interest, even reaching the pilot stage. In addition, recently, several studies have been reported on vitrimers, which are regarded as polymers ranking between thermosets and thermoplastics. In this case, although many articles have reported to date on the thermal degradation of these technical polymers, intensive efforts have been devoted to avoiding the release of low molar mass oligomers and per- and poly-fluoroalkyl substances (PFAS, and especially polymerisation aids such as perfluorooctanoic acid (PFOA) and its alternatives), while various reports demonstrated the complete decomposition of PTFE, leading to the formation of TFE (and hexafluoropropylene or octafluorocyclobutane to a lesser extent). Incineration is one of only a few technologies that can potentially degrade FPs and completely degrade PTFE and other PFAS from 850 °C. Recent studies on the mineralisation of FPs under subcritical water represent an interesting approach to close the loop of the fluorine chemistry cycle. Because of the high molar masses (several million for PTFE) and thermal, chemical, photochemical, and hydrolytic inertness and biological stability of FPs, it has been clearly evidenced that they satisfy the 13 accepted regulatory assessment criteria to be considered as polymers of low concern.

Are (Co)Polymers of 1,1,3,3,3-Pentafluoropropene Possible?

The copolymerization and terpolymerization of 1,1,3,3,3-pentafluoropropene (PFP) with various combinations of fluorinated and hydrogenated comonomers were investigated. The chosen fluoromonomers were vinylidene fluoride (VDF), 3,3,3-trifluoropropene (TFP), hexafluoropropene (HFP), perfluoromethylvinyl ether (PMVE), chlorotrifluoroethylene (CTFE) and tert-butyl-2-trifluoromethacrylate (MAF-TBE), while the hydrocarbon comonomers were vinylene carbonate (VCA), ethyl vinyl ether (EVE) and 3-isopropenyl-α,α-dimethylbenzyl isocyanate (m-TMI). Copolymers of PFP with non-homopolymerizable monomers (HFP, PMVE and MAF-TBE) led to quite low yields, while the introduction of VDF enabled the synthesis of poly(PFP-ter-VDF-ter-M3) terpolymers with improved yields. PFP does not homopolymerize and delays the copolymerizations. All polymers were either amorphous fluoroelastomers or fluorothermoplastics with glass transition temperatures ranging from -56 °C to +59 °C, and they exhibited good thermal stability in air.

One-Step Multifunctionalization of Flax Fabrics for Simultaneous Flame-Retardant and Hydro-Oleophobic Properties Using Radiation-Induced Graft Polymerization.

This study concerns the one-step radiografting of flax fabrics with phosphonated and fluorinated polymer chains using (meth)acrylic monomers: dimethyl(methacryloxy)methyl phosphonate (MAPC1), 2-(perfluorobutyl)ethyl methacrylate (M4), 1H,1H,2H,2H-perfluorooctyl acrylate (AC6) and 1H,1H,2H,2H-perfluorodecyl methacrylate (M8). The multifunctionalization of flax fabrics using a pre-irradiation procedure at 20 and 100 kGy allows simultaneously providing them with flame retardancy and hydro- and oleophobicity properties. The successful grafting of flax fibers is first confirmed by FTIR spectroscopy. The morphology of the treated fabrics, the regioselectivity of grafting and the distribution of the fluorine and phosphorus elements are assessed by scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (SEM-EDX). The flame retardancy is evaluated using pyrolysis combustion flow calorimetry (PCFC) and cone calorimetry. The hydro- and oleophobicity and water repellency of the treated fabrics is established by contact angle and sliding angle measurements, respectively. The grafting treatment of flax irradiated at 100 KGy, using M8 and MAPC1 monomers (50:50) for 24 h, allows achieving fluorine and phosphorus contents of 8.04 wt% and 0.77 wt%, respectively. The modified fabrics display excellent hydro-oleophobic and flame-retardant properties with water and diiodomethane contact angles of 151° and 131°, respectively, and a large decrease in peak of heat release rate (pHRR) compared to pristine flax (from 230 W/g to 53 W/g). Relevant results are also obtained for M4 and AC6 monomers in combination with MAPC1. For the flame retardancy feature, the presence of fluorinated groups does not disturb the effect of phosphorus.

Original Fluorinated Non-Isocyanate Polyhydroxyurethanes.

New fluorinated polyhydroxyurethanes (FPHUs) with various molar weights were synthesized via the polyaddition reaction of a fluorinated telechelic bis(cyclocarbonate) (bis-CC) with a diamine. The fluorinated bis-CC was initially synthesized by carbonylation of a fluorinated diepoxide, 1,4-bis(2',3'-epoxypropyl)perfluorobutane, in the presence of LiBr catalyst, in high yield. Then, several reaction conditions were optimized through the model reactions of the fluorinated bis-CC with hexylamine. Subsequently, fluorinated polymers bearing hydroxyurethane moieties (FPHUs) were prepared by reacting the bis-CC with different hexamethylenediamine amounts in bulk at 80 °C and the presence of a catalyst. The chemoselective polymerization reaction yielded three isomers bearing primary and secondary hydroxyl groups in 61-82% yield. The synthesized fluorinated CCs and the corresponding FPHUs were characterized by 1H, 19F, and 13C NMR spectroscopy. They were compared to their hydrogenated homologues synthesized in similar conditions. The gel permeation chromatography (GPC), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA) data of the FPHUs revealed a higher molar mass and a slight increase in glass transition and decomposition temperatures compared to those of the PHUs.

Dielectric Characterization of Core-Shell Structured Poly(vinylidene fluoride)-grafted-BaTiO3 Nanocomposites.

Dielectric properties of poly(vinylidene fluoride)-grafted-BaTiO3 (PVDF-g-BT) core-shell structured nanocomposites obtained from Reversible Addition Fragmentation chain Transfer (RAFT) polymerization of VDF were investigated by Broadband Dielectric Spectroscopy (BDS). The dielectric constant increased along with the BT content, about +50% by addition of 15 vol% of BT, which was around 40% more than expected from predictions using the usual dielectric modeling methods for composite materials, to be ascribed to the effect of the interfacial core-shell structure. The known dielectric relaxations for PVDF were observed for the neat polymer as well as for its nanocomposites, not affected by the presence of nanoparticles. A relaxation process at higher temperatures was found, due to interfacial polarization at the amorphous-crystalline interface, due to the high crystallinity of materials produced by RAFT. Isochronal BDS spectra were exploited to detect the primary relaxation of the amorphous fraction. Thermal analysis demonstrated a very broad endotherm at temperatures much lower than the usual melting peaks, possibly due to the ungrafted fraction of the polymer that is more easily removable by repeated washing of the pristine material with acetone.

Growth-Induced Wrinkles and Dotlike Patterns of a Swollen Fluoroalkylated Thin Film by the Reaction of Surface-Attached Polymethylhydrosiloxane.

The design of hydrophobic surfaces requires a material which has a low solid surface tension and a simple fabrication process for anchoring and controlling the surface morphology. A generic method for the spontaneous formation of robust instability patterns is proposed through the hydrosilylation of a fluoroalkene bearing dangling chains, Rf = C6F13(CH2)3-, with a soft polymethylhydrosiloxane (PMHS) spin-coated gel polymer (0.8 µm thick) using Karstedt catalyst. These patterns were easily formed by an irreversible swelling reaction due to the attachment of a layer to various substrates. The buckling instability was created by two different approaches for a gel layer bound to a rigid silicon wafer substrate (A) and to a soft nonswelling silicone elastomer foundation (B). The observations of grafted Rf-PMHS films in the swollen state by microscopy revealed two distinct permanent patterns on various substrates: dotlike of wavelength λ = 0.4-0.7 µm (A) or wrinkle of wavelength λ = 4-7 µm (B). The elastic moduli ratios of film/substrate were determined using PeakForce quantitative nanomechanical mapping. The characteristic wavelengths (λ) of the patterns for systems A and B were quantitatively estimated in relation to the thickness of the top layer. A diversity of wrinkle morphologies can be achieved by grafting different side chains on pristine PMHS films. The water contact angle (WCA) hysteresis of fluorinated chain (Rf) was enhanced upon roughening the surfaces, giving highly hydrophobic surface properties for water with static/hysteresis WCAs of 136°/74° in the resulting wrinkle (B) and 119°/41° in the dotlike of lower roughness (A). The hydrophobic properties of grafted films on A with various mixtures of hexyl/fluoroalkyl chains were characterized by static CA: WCA 104-119°, ethylene glycol CA 80-96°, and n-hexadecane CA 17-61°. A very low surface energy of 15 mN/m for Rf-PMHS was found on the smoother dotlike pattern.

Plant-environment microscopy tracks interactions of Bacillus subtilis with plant roots across the entire rhizosphere.

Our understanding of plant-microbe interactions in soil is limited by the difficulty of observing processes at the microscopic scale throughout plants' large volume of influence. Here, we present the development of three-dimensional live microscopy for resolving plant-microbe interactions across the environment of an entire seedling growing in a transparent soil in tailor-made mesocosms, maintaining physical conditions for the culture of both plants and microorganisms. A tailor-made, dual-illumination light sheet system acquired photons scattered from the plant while fluorescence emissions were simultaneously captured from transparent soil particles and labeled microorganisms, allowing the generation of quantitative data on samples ∼3,600 mm3 in size, with as good as 5 µm resolution at a rate of up to one scan every 30 min. The system tracked the movement of Bacillus subtilis populations in the rhizosphere of lettuce plants in real time, revealing previously unseen patterns of activity. Motile bacteria favored small pore spaces over the surface of soil particles, colonizing the root in a pulsatile manner. Migrations appeared to be directed toward the root cap, the point of "first contact," before the subsequent colonization of mature epidermis cells. Our findings show that microscopes dedicated to live environmental studies present an invaluable tool to understand plant-microbe interactions.

Trends in the Diels-Alder reaction in polymer chemistry.

The Diels-Alder (DA) reaction is regarded as quite a useful strategy in organic and macromolecular syntheses. The reversibility of this reaction and the advent of self-repair technology, as well as other applications in controlled macromolecular architectures and crosslinking, have strongly boosted the research activity, which is still attracting a huge interest in both academic and industrial research. The DA reaction is a simple and scalable toolbox. Though it is well-established that furan/maleimide is the most studied diene/dienophile couple, this perspective article reports strategies using other reversible systems with deeper features on other types of diene/dienophile pairs being either petro-sourced (cyclopentadiene, anthracene) or bio-sourced (muconic and sorbic acids, myrcene and farnesene derivatives, eugenol, cardanol). This review is composed of four sections. The first one briefly recalls the background on the DA reactions involving cyclodimerizations, dienes, and dienophiles, parameters affecting the reaction, while the second part deals with the furan/maleimide reaction. The third one deals with petro-sourced and bio-sourced (or products becoming bio-sourced) reactants involved in DA reactions are also listed and discussed. Finally, the authors' opinion is given on the potential future of the crosslinking-decrosslinking reaction, especially regarding the process (e.g., key temperatures of decrosslinking) or possibly monocomponents. It presents both fundamental and applied research on the DA reaction and its applications.

Cobalt-Mediated Radical Copolymerization of Vinylidene Fluoride and 2,3,3,3-Trifluoroprop-1-ene.

New copolymers based on vinylidene fluoride (VDF) and 2,3,3,3-tetrafluoroprop-1-ene (1234yf) were synthesized by organometallic-mediated radical copolymerization (OMRcP) using the combination of bis(tert-butylcyclohexyl) peroxydicarbonate initiator and bis(acetylacetonato)cobalt(II), (Co(acac)2) as a controlling agent. Kinetics studies of the copolymerization of the fluoroalkenes copolymers were monitored by GPC and 19F NMR with molar masses up to 12,200 g/mol and dispersities (D) ranging from 1.33 to 1.47. Such an OMRcP behaves as a controlled copolymerization, evidenced by the molar mass of the resulting copolymer-monomer conversion linear relationship. The reactivity ratios, ri, of both comonomers were determined by using the Fineman-Ross and Kelen-Tüdos fitting model leading to rVDF = 0.384 ± 0.013 and r1234yf = 2.147 ± 0.129 at 60 °C, showing that a lower reactivity of VDF integrated in the copolymer to a greater extent leads to the production of gradient or pseudo-diblock copolymers. In addition, the Q (0.03) and e (0.06 and 0.94) parameters were assessed, as well as the dyad statistic distributions and mean square sequence lengths of PVDF and P1234yf.

Unexpected Radical Telomerisation of Vinylidene Fluoride with 2-Mercaptoethanol.

The radical telomerisation of vinylidene fluoride (VDF) with 2-mercaptoethanol as chain transfer agent (CTA) was studied to synthesise fluorinated telomers which bear a hydroxy end-group, such as H(VDF)nS(CH2)2OH, under thermal (di-tert-butyl peroxide as the initiator) or photochemical initiations. A careful structural study of a typical H-VDF-S(CH2)2OH telomer was performed by 1H and 19F NMR spectroscopy. These analytical methods allowed us to explore the selective addition of the thiyl radical onto the hydrogenated side of VDF, and the telomer containing one VDF unit was obtained selectively. Surprisingly, for higher [VDF]o initial concentrations, a monoadduct telomer was produced as well as PVDF homopolymer. This feature was related to the fast consumption of the CTA. The kinetics of radical telomerisation led to a quite high transfer constant of the CTA (40 at 140 °C) that evidences the formation of a monoadduct as the only telomer formed.

Synthesis of size-controlled and highly monodispersed silica nanoparticles using a short alkyl-chain fluorinated surfactant.

Highly monodispersed silica nanoparticles (SiNPs) were synthesised using a fluorinated surfactant, HOCH2CH(CF3)CO2H, and its efficiency was compared with efficiencies of five other surfactants. The size of the SiNPs (∼50-200 nm) was controlled by controlling the surfactant amount. The short alkyl-chain fluoro surfactant was found to be more efficient at producing monodispersed SiNPs than its long alkyl-chain fluoro or non-fluorinated surfactant counterparts.

Solid-Liquid Europium Ion Extraction via Phosphonic Acid-Functionalized Polyvinylidene Fluoride Siloxanes.

Novel triethoxysilane and dimethyl phosphonate functional vinylidene fluoride (VDF)-containing terpolymers, for potential applications in Eu ion extraction from water, were produced by conventional radical terpolymerization of VDF with vinyltriethoxylsilane (VTEOS) and vinyldimethylphosphonate (VDMP). Although initial attempts for the copolymerization of VTEOS and VDMP failed, the successful terpolymerization was initiated by peroxide to lead to multiple poly(VDF-ter-VDMP-ter-VTEOS) terpolymers, that had different molar percentages of VDF (70-90 mol.%), VTEOS (5-20 mol.%) and VDMP (10 mol.%) in 50-80% yields. The obtained terpolymers were characterized by 1H, 19F, 29Si and 31P NMR spectroscopies. The crosslinking of such resulting poly(VDF-ter-VDMP-ter-VTEOS) terpolymers was achieved by hydrolysis and condensation (sol-gel process) of the triethoxysilane groups in acidic media, to obtain a 3D network, which was analyzed by solid state 29Si and 31P NMR spectroscopies, TGA and DSC. The thermal stability of the terpolymers was moderately high (up to 300 °C under air), whereas they display a slight increase in their crystallinity-rate from 9.7% to 12.1% after crosslinking. Finally, the dimethyl phosphonate functions were hydrolyzed into phosphonic acid successfully, and the europium ion extraction capacity of terpolymer was studied. The results demonstrated a very high removal capacity of Eu(III) ions from water, up to a total removal at low concentrations.

May Trifluoromethylation and Polymerization of Styrene Occur from a Perfluorinated Persistent Radical (PPFR)?

The radical polymerization of styrene (St) initiated by a trifluoromethyl radical generated from a perfluorinated highly branched persistent radical (PPFR) is presented with an isolated yield above 70 %. The release of . CF3 radical occurred from a temperature above 85 °C. Deeper 1 H and 19 F NMR spectroscopies of the resulting fluorinated polystyrenes (CF3 -PSts) evidenced the presence of both CF3 end-group of the PSt chain and the trifluoromethylation of the phenyl ring (in meta-position mainly). [PPFR]0 /[St]0 initial molar ratios of 3:1, 3:10 and 3:100 led to various molar masses ranging from 1750 to 5400 g mol-1 in 70-86 % yields. MALDI-TOF spectrometry of such CF3 -PSts highlighted polymeric distributions which evidenced differences between m/z fragments of 104 and 172 corresponding to styrene and trifluoromethyl styrene units, respectively. Such CF3 -PSt polymers were also compared to conventional PSts produced from the radical polymerization of St initiated by a peroxydicarbonate initiator. A mechanism of the polymerization is presented showing the formation of a trifluoromethyl styrene first, followed by its radical (co)polymerization with styrene. The thermal properties (thermal stability and glass transition temperature, Tg ) of these polymers were also compared and revealed a much better thermal stability of the CF3 -PSt (10 % weight loss at 356-376 °C) and a Tg of around 70 °C.

Molecular Aggregation Structure and Surface Properties of Biomimetic Catechol-Bearing Poly[2-(perfluorooctyl)ethyl acrylate] and Its Application to Superamphiphobic Coatings.

The molecular aggregation structure and surface properties of a catechol-bearing fluoropolymer, P(FAC8-co-DOPAm), which was synthesized by conventional radical copolymerization of 2-(perfluorooctyl)ethyl acrylate (FAC8) and N-(3,4-dihydroxyphenethyl)acrylamide (DOPAm), and its application to the superamphiphobic surfaces are presented. The crystallinity of P(FAC8-co-DOPAm) was lower than that of poly[2-(perfluorooctyl)ethyl acrylate] (PFAC8). The perfluoroalkyl (Rf) groups were ordered on the surface with CF3 terminals exposed to air, and the Rf ordering was influenced by thermal history: the thermally annealed film exhibited higher Rf ordering than the unannealed one. The surface free energy was estimated to be γ = 7.32 mJ m-2 for both the unannealed and annealed films. Based on contact angle measurement, various interfacial structures of water and oils in accordance with the surface aggregation structure of Rf groups were proposed. Dewetting of the PFAC8 film at elevated temperature was suppressed by the introduction of catechol groups in the backbone. The degradation temperature of PFAC8 was improved significantly, and the evaporation of the low molar mass-polymer was inhibited by the introduction of catechol groups under both nitrogen and air atmospheres. The hydrophobicity of the copolymer films could be healed after the surface was damaged by vacuum ultraviolet (VUV) irradiation. This copolymer was used to create superamphiphobic fabrics and halloysite nanotube (HNT)-based organic/inorganic hybrid coatings successfully. Wetting behaviors of the superamphiphobic fabrics and coatings both follow the Cassie-Baxter wetting model.