Fluorinated vinyl ether homopolymers and copolymers: Living cationic polymerization and temperature‐induced solubility transitions in various organic solvents including perfluoro solvents

Partially fluorinated poly(vinyl ether)s with C₄F₉ and C₆F₁₂H groups in the side chain were synthesized via living cationic polymerization in the presence of an added base in a fluorine‐containing solvent, dichloropentafluoropropanes. For comparison, the polymerization of vinyl ether monomers with C₂F₅ and C₆F₁₃ groups and nonfluorinated monomers were also carried out. The characterization of the product polymers using size exclusion chromatography with a fluorinated solvent as an eluent indicated that all polymers had narrow molecular weight distributions (M_w/M_n ～ 1.1). Interestingly, the moderately fluorinated polymers with C₄F₉ exhibited upper critical solution temperature‐type phase separation in various organic solvents with wide‐ranging polarities, whereas highly fluorinated polymers with C₆F₁₃ are insoluble in nonfluorinated solvents. Polymers with C₄F₉ groups exhibited temperature dependent solubility transitions not only in common organic solvents (e.g., toluene, chloroform, tetrahydrofuran, and acetone) but also in perfluoro solvents [e.g., perfluoro(methylcyclohexane) and perfluorodecalin]. On the other hand, the solubility of polymers with C₆F₁₂H showed completely different from that of polymers with C₆F₁₃, despite their similar fluorine content. In addition, various types of fluorinated block copolymers were prepared in a living manner. The block copolymers with a thermosensitive fluorinated segment underwent temperature‐induced micellization and sol–gel transition in various organic solvents. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Mechanical property tuning of semicrystalline network polymers by controlling rates of crystallization and crosslinking

Semicrystalline network polymers were obtained by the Diels–Alder (DA) reaction of furyl‐telechelic poly(ε‐caprolactone) and tris(2‐maleimide ethyl)amine. Controlling the rates of crystallization and crosslinking reaction gave materials with various properties. Curing at a temperature much below T_m of poly(ε‐caprolactone), at which crystallization proceeded first followed by DA reaction, gave a hard and stiff material, whereas curing above T_m gave a soft and stretchable one. When crystallization and crosslinking were promoted simultaneously, tough and ductile materials were obtained. Structural analysis of the network polymers showed that the variation in the properties was derived from the difference in the crystallinity, crystallite size, and network structure. Therefore, materials with various mechanical properties, from soft to hard, could be obtained by simple thermal treatment. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Fluorinated vinyl ethers as new surface agents in the photocationic polymerization of vinyl ether resins

The syntheses of fluorinated vinyl ethers (H₂C?CHOCH₂CH₂C_nF_2n+1, n = 6 or 8) and their copolymerizations with bis(4‐vinyloxybutyl) isophthalate are reported. The fluorinated monomers were prepared by the transetherification of ethyl vinyl ether and fluorinated alcohols in a 75% yield. Added in low concentrations (0.1–3.0 wt %) to formulations containing bis(4‐vinyloxybutyl) isophthalate, they did not affect the kinetics of the cationic photopolymerization. The cured films were transparent and showed interesting properties in terms of wettability, hardness, cross‐cut adhesion, and chemical inertness. The fluoromonomers increased the hydrophobicity of the film surface, whereas the adhesion on various substrates such as glass and wood was unchanged. An increase in the methyl ethyl ketone resistance was also observed. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2890–2897, 2003     

New fluorinated acrylic monomers for the surface modification of UV‐curable systems

New fluorinated acrylates were synthesized and used as modifying additives for acrylic UV‐curable systems. Their chemical structure is: C_nF_2n+1 R—OCO—CHCH₂, where the linear perfluorinated chain contains from 4 to 10 carbon atoms, while R is a linear alkyl group containing or not a thioether group. Notwithstanding their very low concentration, the fluorinated monomers caused a dramatic change of the surface properties of the films, without changing their curing conditions and their bulk properties. X‐ray photoelectron spectroscopy measurements showed that the monomers were able to concentrate selectively on the surfaces of the films, depending on their chemical structure and on the kind of substrate employed. The synthesis of the fluorinated monomers and the relationship between their chemical structure and the final surface properties of the UV‐cured films will be discussed. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 77–87, 1999     

Dispersion of silica nanoparticles bearing perfluorohexyl units into fluorinated copolymers

This study aims at determining the compatibility behavior of nanoparticles surface with fluorinated matrices to obtain a homogenous dispersion and better composites properties. First, modified silica nanoparticles by C₆F₁₃I and C₆F₁₃‐C₂H₄‐SH led to various fluorinated silica of different massic concentrations and grafting rates. The dispersion of these nanoparticles (in 5 wt %) into molten poly(VDF‐co‐HFP) and poly(TFE‐co‐HFP) matrices were studied as well as the hydrophobic, mechanical, and thermal properties of both fluorinated copolymers and resulting composites. In both series, the storage modulus of nanocomposites increased while the melting (T_m) and decomposition (T_10%) temperatures varied with the polymer matrix. They increased for poly(VDF‐co‐HFP) composites (T_m= 134 to 144 °C and T_10%= 441 to 464 °C) but decreased for poly(TFE‐co‐HFP) nanocomposites (T_m= 276 to 268 °C and T_10%= 488 to 477 °C). © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1512–1522     

Novel synthesis of polyimide–polyhybridsiloxane block copolymers via polyhydrosilylation: Characterization and physical properties

The insertion of soft polysiloxane segments into a polyimide backbone introduces changes in its properties (processability, low surface tension, gas permeability, and lower dielectric constant). Generally, these polyimide–polysiloxane copolymers are synthesized by the condensation of a dianhydride with an aromatic diamine and an amine telechelic polysiloxane, or by transimidization between an aminopyridine‐terminated oligoimide and an amine end‐capped oligosiloxane. This study investigated another route to obtain perfectly alternating polyimide–polyhybridsiloxane (PI–PHSX) block copolymers. The hydrosilylation, widely studied previously, was performed to elaborate copolymers from an allyl telechelic polyimide and a hydrosilane telechelic polyhybridsiloxane. The use of a telechelic polyhybridsiloxane as a soft segment brought better thermostability and better chemical resistance in comparison with an oligosiloxane based on ? Si(CH₃)₂? O? units. Using the same allyl telechelic polyimide moiety but varying the size of the hybrid siloxane part, we obtained different PI–PHSX block copolymers, leading to thermoplastic elastomers (TPE). We investigated the effect of the soft‐segment length on the thermal resistance, activation energy of thermal degradation, mechanical behavior, and surface properties of a series three PI–PHSX block copolymers containing 36, 54, and 75 wt % polyimide. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2414–2425, 2001     

Fluorinated polymerizable phosphonium salts from PH3: Surface properties of photopolymerized films

An array of highly fluorinated polymerizable phosphonium salts (HFPPS) were synthesized from PH₃ and utilized in UV‐curable formulations. Inclusion of these salts at very low loading (0.1–1 wt %) into hexanediol diacrylate (HDDA) resulted in hydrophobic surfaces. The water repellency was achieved with short C₄F₉ fluorocarbon appendages in the monomer as opposed to the bioaccumulative C₈F₁₇ appended polymers. The physical properties of these new monomers were also characterized. The molecular architecture of the monomers had a pronounced effect on both their physical properties along with the degree of hydrophobicity imparted in the polymer. Salts utilizing the bis(trifluoromethylsulfonyl)imide anion displayed excellent compatibility with HDDA, while the chloride salts were insoluble. Time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS) confirmed the presence of the HFPPS at the surface of the polymer coating. For the first time this demonstrates how these salts may be used to functionalize the surface of a UV‐cured film with ionic species. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2782–2792     

Synthesis of fluorine‐containing star‐shaped poly(vinyl ether)s via arm‐linking reactions in living cationic polymerization

Various types of fluorine‐containing star‐shaped poly(vinyl ether)s were successfully synthesized by crosslinking reactions of living polymers based on living cationic polymerization. Star polymers with fluorinated arm chains were prepared by the reaction between a divinyl ether and living poly(vinyl ether)s with fluorine groups (C₄F₉, C₆F₁₃, and C₈F₁₇) at the side chain using cationogen/Et_1.5AlCl_1.5 in a fluorinated solvent (dichloropentafluoropropanes), giving star‐shaped fluorinated polymers in high yields with a relatively narrow molecular weight distribution. The concentration of living polymers for the crosslinking reaction and the molar feed ratio of a bifunctional vinyl ether to living polymers affected the yield and molecular weight of the star polymers. Star polymers with block arms were prepared by a linking reaction of living block copolymers of a fluorinated segment and a nonfluorinated segment. Heteroarm star‐shaped polymers containing two‐ or three‐arm species were synthesized using a mixture of different living polymer species for the reaction with a bifunctional vinyl ether. The obtained polymers underwent temperature‐induced solubility transitions in various organic solvents, and their concentrated solutions underwent sol–gel transitions, based on the solubility transition of a thermoresponsive fluorinated segment. Furthermore, a slight amount of fluorine groups were shown to be effective for physical gelation when those were located at the arm ends of a star polymer. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Synthesis of hybrid fluorinated silicones. I. Influence of the spacer between the silicon atom and the fluorinated chain in the preparation and the thermal properties of hybrid homopolymers

The synthesis of fluorinated hybrid silicones prepared in three steps from H₂C CH—C₆F₁₂ CH CH₂(I) and H₂C CHCH₂—C₆F₁₂—CH₂CH CH₂(II) is presented. First, both hydrosilylations of chlorodimethylsilane with these nonconjugated dienes were carried out in the presence of the Speier's catalyst leading to the expected bis-chlorosilane in excellent yield from (II) but giving a rearranged by-product from (I). However, a similar reaction from (I) initiated by a peroxide produced the expected bis-chlorosilane selectively. Second, these chlorosilanes were quantitatively hydrolyzed into the corresponding α,ω-bis silanols, whatever the spacer between the fluorinated group and the silicon atom. Finally, the polycondensations of these bis silanols were performed in the presence of an amine/acid adduct catalyst. Interestingly, the dihydroxysilane produced from (I) reacts much quicker than the other one. Moreover, thermal properties (T_g, T_dec) were investigated and compared to those of commercially available fluorosilicones or mentioned in the literature and show improvement of the behavior of these fluorosilicones at low and high temperatures. © 1996 John Wiley & Sons, Inc.     

Reactions of salicylaldehyde with tris(pentaf luorophenyl)silanes and secondary amines

Reactions of tris(pentafluorophenyl)silanes RSi(C₆F₅)₃ with salicylaldehyde and secondary amines were studied. The reactions afforded α-pentafluorophenyl-substituted amines. Silanes RSi(C₆F₅)₃ (R = Me, Ph, C₆F₅, CH₂CH=CH₂, and CH=CH₂) were found to be efficient reagents for transfer of the C₆F₅ group to the iminium cation generated from salicylaldehyde and amine. However, tris(pentafluorophenyl)phenylethynyl-and tris(pentafluorophenyl)silanes were not able to serve as a source of a fluorinated substituent because of competitive transfer of acetylenide fragment or hydride. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 498–503, March, 2006.     

Synthesis and surface activities of organic solvent-soluble fluorinated surfactants

A variety of fluorinated surfactants soluble in organic solvent were prepared, including C₈F₁₇SO₂NHC_nH_2n+1 (n = 2, 4, 6, 8, 10), C₈F₁₇SO₂NHR (R = C₆H₁₁, C₆H₅), C₈F₁₇SO₂N(C_nH_2n+1)₂ (n = 1, 2, 3, 4) and C₈F₁₇SO₂NH(CH₂)_nNHO₂SC₈F₁₇ (n = 6, 10). Their surface activities in various organic solvents were determined by surface tension measurement. The results showed that these fluorinated surfactants can reduce the surface tension of both polar and non-polar organic solvents. In general, organic solvents with strong polarity or long alkyl chain are beneficial to increase the surface activity of these polar fluorinated surfactants. By comparing fluorinated surfactants with the same fluorocarbon segment and connecting group, C₈F₁₇SO₂N(C_nH_2n+1)₂ (n = 1, 2, 3, 4) showed lower surface activity in organic solvents than C₈F₁₇SO₂NHC_nH_2n+1 (n = 2, 4, 6, 8) with an equal carbon number of the solvophilic group. Through surface tension vs. concentration curves given for N-octyl perfluorooctanesulfonamide in various organic solvents, a break point like the critical micelle concentration of ordinary surfactants in aqueous solutions was observed, and the effect of the different types of organic solvents on adsorption and aggregation behavior was also studied.     

Synthesis and properties of new fluorinated ester,thioester, and amide substituted polythiophenes. Towards superhydrophobic surfaces

A series of new fluorinated polythiophenes has been synthesized by oxidative chemical and electrochemical polymerization and by Ullmann coupling. The substitution with the perfluoroalkyl alkyl chain CH₂CH₂C₆F₁₃ on the 3 position of the thiophene ring is performed via an ester, thioester, or amide connector, (CH₂)_m‐C(O)X, m = 0–2, with a view to investigating the role of the linker on the polymerization and on the properties of the corresponding polymers. The bromination of the monomers at the 2 and 5 positions allows the use of Ullmann coupling to form soluble fluorinated oligomers. The electron affinity was determined from cyclic voltammetry and a value of 3.1 eV was found for the ester derivative; such materials represent interesting candidates for use in light‐emitting devices or as an electron accepting material in photodiodes/solar cells. The oxidative polymerizations need the connector to be spaced out from the heterocycle to reduce its withdrawal effect. The ester, thioester, and amide spacer determined to a large extent the efficiency of the oxidative polymerization, and particularly the electropolymerization, as well as the solubility of the polymers formed. All the polymers were analyzed by GPC and by UV–visible and fluorescence spectroscopies. The electrochemical oxidation of the thioester and amide group prevents the formation of electroactive films by electropolymerization. But in the case of the ester group, the electroformed polymer exhibits exceptional stable superhydrophobic and lipophobic properties because of a porous surface and the presence of a fluorinated chain that confers low surface energy. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4707–4719, 2007     

Fluorinated sulfonate surfactants

New classes of fluorinated sulfonate surfactants were synthesized in which a perfluoroalkyl chain is interrupted either by an ether oxygen (–O–), or by methylene (–CH₂–) units. Both classes of molecules involve multi-step syntheses. The fluoroether sulfonates (RfOCF₂CF₂CH₂CH₂SO₃H, Rf = C₂F₅, C₃F₇) were achieved in four steps including fluoroiodonation of perfluorovinyl ethers (RfCF = CF₂), ethylation, chlorination and hydrolysis. The methylene interrupted fluorosulfonates (RfCH₂CF₂CH₂CH₂SO₃H, Rf = C₄F₉, C₆F₁₃) were also prepared in four steps involving vinylidene fluoride insertion of fluoroalkyl iodides, ethylene insertion, chlorination and hydrolysis. All intermediates and final products were well characterized by ¹H and ¹⁹F NMR. These new fluorinated surfactants were compared to a commercially available fluorosulfonate (C₆F₁₃CH₂CH₂SO₃H) for surface activity. These materials match the surface tensions of commercial fluorosurfactant yet are more efficient because they have lower fluorine content.     

Synthesis of symmetric and dissymetric bisperfluoroalkanesulfonylimides and evaluation of their inhibition on bovine carbonic anhydrase

This study describes a synthesis of symmetric and dissymmetric bis[(perfluoroalkane)‐sulfonyl]imides by the reaction of the sodium salt of perfluoroalkanesulfonamide R_FSO₂NH⁻Na⁺ (R_F = C₄F₉, C₆F₁₃, C₈F₁₇) with hexamethyldisilazane and perfluoroalkanesulfonylfluoride R_FSO₂F (R_F = C₄F₉, C₆F₁₃, C₈F₁₇). They are obtained, in two steps, in moderate overall yield. Moreover, this paper provides a study of their inhibition on bovine carbonic anhydrase. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:542–548, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20452     

The Effect of –(C6F4)– on the Surface Free Energy of Main‐Chain Liquid Crystalline and Crystalline Polymers

Novel fluorinated main‐chain liquid‐crystalline/crystalline polymers were prepared through thin film polymerization to investigate the effect of –(C₆F₄)– on the surface free energy. The fluorine in the phenyl rings does not lower the total surface free energy of the thin copolymer films, compared to those without fluorine. Interestingly, the Lewis acid components (γ⁺) of the surface free energy of the fluorine‐containing polymers increase with an increase in the –(C₆F₄)– content, indicating the increasing electron accepting character of the surface.     

La fluoration de l'hexachlorobenzene et de la pentachloropyridine en milieu de fluorure de potassium solide

The fluorinations of hexachlorobenzene and pentachloropyridine were carried out in sealed tubes with KF in presence of inert gas; the fluorinated derivatives C₆F_xCl_y x + y = 6 0?x?6 and C₅F_xCl_yN x + y = 5 0?x?5 are obtained. The influence of contact time, temperature and the concentration of the ion F^? are investigated and compared; the molar yield varied from 45% to 90%. It is possible to get directly and selectively some fluorinated derivatives as C₅Cl₂F₃N. The fluorinations in liquid KFKCl and solid KF are compared.     

Synthesis and properties of fluorosilicone with perfluorooctylundecyl side chains

A series of fluorosilicone (FLS) homopolymers with 4,4,5,5,6,6,7,7,8,8, 9,9,10,10,11,11,11‐heptadecafluoroundecylmethylsiloxane [? C₈F₁₇CH₂CH₂CH₂(CH₃) SiO? ; HDFUSiO] and copolymers based on dimethylsiloxane [? (CH₃)₂SiO? ] were prepared by the hydrosilylation of 4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,11‐heptadecafluoro‐1‐undecene (C₈F₁₇CH₂CH?CH₂) with poly(hydromethylsiloxane)s. Thermal characterization showed that the decomposition of fluoroalkyl side chains occurred at about 245 °C. Side‐chain crystallization was observed for FLSs with more than 30 mol % HDFUSiO. The refractive index decreased with increasing HDFUSiO content. The dielectric constant increased with increasing HDFUSiO content. The liquid surface tension of the FLS containing 10 mol % HDFUSiO was as low as that of the highly fluorinated FLSs. FLSs with HDFUSiO and trichlorosilylethyl side chains (Cl₃SiCH₂CH₂? ) were also prepared so that their solid surface tension (surface free energy) could be measured. The surface free energy of these FLSs decreased with increasing Cl₃SiCH₂CH₂? content, but the sliding angle of a water droplet and the contact‐angle hysteresis adversely increased. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2704–2714, 2003     

Carbon-Fluorine Bondings of Fluorinated Fullerene and Graphite

Carbon-fluorine bondings of fluorinated fullerenes and fluorine-graphite intercalation compound C_xF were investigated in detail on the basis of XPS data and the potential model using the charge distribution calculated by semiempirical method. It has been confirmed by the present study that two peaks in the C_1s spectra observed for fluorinated fullerenes are assigned to carbon atoms bonded to fluorine atoms and those unbound to fluorine atoms, and the small difference in charges and Madelung potentials of fluorine atoms in different circumstances well explains the single peak in F_1s spectra of fluorinated fullerenes. In the calculated structures of 1,3-C₆₀F₂ and 1,2-C₆₀F_x (x = 2?6) used as the models of C_xF, three kinds of carbon-fluorine bondings were observed corresponding to nearly ionic, semicovalent and covalent C? F bondings. The calculated result supports that the bi-intercalation structure of stage 1 C_xF consists of nearly ionic and semi-covalent fluorines.     

A novel dispersant for preparation of high loading and photosensitive carbon black dispersion

High loading of stable carbon black (CB) dispersion in organic solvent, PGMEA, was prepared by a ball‐milling process when using poly(styrene‐EHA‐HEMA)‐block‐poly(styrene‐EHA‐HEMA‐DMAEMA) (P(SEH)‐b‐P(SEHD)) as a dispersant. The P(SEH)‐b‐P(SEHD) containing P(SEH) as a steric chain and P(SEHD) as an anchoring chain was prepared by TEMPO‐mediated polymerization. The tertiary amine group of DMAEMA in P(SEHD) chain could be adsorbed onto CB by the interaction with the carboxylic acid group on surface of CB and the P(SEH) chain could provide sufficiently steric repulsion force to avoid the aggregation of CB. In addition, a photosensitive dispersant, P(SEH)‐b‐P(SEHD)_C?C, containing the methacrylate double bond side group was also synthesized and was used to prepare stable CB dispersion in PGMEA. The effects of the molecular weight between steric and anchoring chains, the content of tertiary amine, and the amount of methacrylate double bond in the dispersant on the particle size of CB were investigated. Furthermore, the influences of various surface properties of CB, such as specific surface area, content of carboxylic acid group, and size of primary particle, on the particle size of CB in dispersion were also discussed. Finally, the photosensitivity of P(SEH)‐b‐P(SEHD)_C?C/CB composite was monitored by a photodifferential scanning calorimeter. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6185–6197, 2008     

Synthesis and characterization of fluorinated telomers containing vinylidene fluoride and hexafluoropropene from 1,6‐diiodoperfluorohexane

The synthesis of original fluorinated (co)telomers containing vinylidene fluoride (VDF) or VDF and hexafluoropropene (HFP) was achieved by radical telomerizations and (co)telomerizations of VDF (or VDF and HFP) in the presence of 1, 6‐diiodoperfluorohexane via a semisuspension process. tert‐Butyl peroxypivalate (TBPPi) was used as an efficient thermal initiator. The numbers of VDF and VDF/HFP base units in the (co)telomers were determined by ¹⁹F and ¹H NMR spectroscopy. They ranged from 10 to 190 VDF base units. Fluorinated telomers of various molecular weights (1200–12,600 g/mol) were obtained by the alteration of the initial [1,6‐diiodoperfluorohexane]₀/[fluoroalkenes]₀ and [TBPPi]₀/[fluoroalkenes]₀ molar ratios. The thermal properties of these fluorinated (co)telomers, such as the glass‐transition temperature and melting temperature, were examined. As expected, these telomers exhibited good thermal stability. They were stable at least up to 350 °C. The compounds containing more than 30 VDF units were crystalline, whereas all those containing VDF‐co‐HFP were amorphous with elastomeric properties, whatever the number was of the fluorinated base units. The structures of I–(VDF)_n–R_F–(VDF)_m–I and I–(HFP)_x(VDF)_n–R_F–(VDF)_m(HFP)_y–I (co)telomers were obtained, and the defects of the VDF chain and the ? CH₂CF₂I and ? CF₂CH₂I functionalities were studied successfully (where R_F = C₆F₁₂). The functionality in the iodine atoms was modified: the higher the VDF content in the telomers, the lower the normal end functionality (? CH₂CF₂I) and the higher the reversed extremity (? CF₂CH₂I). In addition, the percentage of defects increased when the number of VDF units increased. The molecular weights and molecular weight distributions of different telomers and cotelomers were also studied. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1470–1485, 2006