Synthesis of small-molecule initiators derived from fluorinated acrylates and their application in atom transfer radical polymerization (ATRP)

The bromo-terminated small-molecule initiator was prepared by the direct addition reaction of 2,2,3,4,4,4-hexafluorobutyl methacrylate (HFMA) or dodecafluoroheptyl methacrylate (DFMA) with hydrobromic acid in acetic acid under mild conditions. This greatly widened the initiators used for atom transfer radical polymerization (ATRP). The successful polymerization of isobutyl methacrylate (IBMA) or methyl methacrylate (MMA) derived from HFMA-Br or DFMA-Br indicated that fluorinated acrylates could be used as initiators for ATRP. The data of GPC showed the well controlling of the initiator system. FTIR and ¹H NMR characterized the structures of the initiators and their polymers. Contact angle measurement indicated that although only one molecule of fluorinated acrylate was introduced, the surface properties of polymers were improved greatly.     

POSS‐based fluorinated azobenzene‐containing polymers: Photo‐responsive behavior and evaluation of water repellency

The photoresponsive polyhedral oligomeric silsesquioxanes (POSS) based fluorinated azobenzene‐containing polymers were prepared and characterized by NMR, FT‐IR, GPC, XRD, TG and UV–Vis spectra. The thermal property of the polymers was improved by the introduction of POSS cage. The trans‐cis photoisomerization of the polymers in solution was similar to that of the fluorinated azobenzene monomer and in accordance with the first‐order reaction kinetics equation within the first 250 seconds UV irradiation. The cotton fabrics coated with the polymers showed excellent water repellency and possessed switchable wettability under UV irradiation. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43540.     

Facile preparation and characterization of novel fluoroalkyl end‐capped oligomer/zinc oxide nanocomposites

BACKGROUND: The aim of the present work was to prepare novel fluoroalkyl end‐capped oligomer/zinc oxide nanocomposites by the use of fluoroalkyl end‐capped oligomers as key intermediates. In addition, it was intended to clarify the unique properties of these fluorinated nanocomposites. RESULTS: A variety of fluoroalkyl end‐capped oligomer/zinc oxide nanocomposites were prepared by the interaction of the corresponding oligomers with zinc oxide particles, which were obtained by the reaction of zinc acetate dihydrate with sodium hydroxide in ethanol solution at room temperature. In contrast, fluoroalkyl end‐capped 2‐methacryolyoxyethanesulfonic acid oligomer was found to afford the corresponding fluorinated amorphous zinc oxide composites under similar conditions. CONCLUSION: These fluorinated zinc oxide composites thus obtained are nanometer size‐controlled very fine particles, and they exhibit a good dispersibility and stability in water and traditional organic media. These fluorinated nanocomposites were also applied for the surface modification of poly(methyl methacrylate) (PMMA) films, which gave not only a good surface‐active property imparted by fluorine but also unique characteristics related to the presence of zinc oxide nanoparticles on the modified PMMA film surface. Copyright © 2008 Society of Chemical Industry     

Surface properties and chain structure of fluorinated acrylate copolymers prepared by emulsion polymerization

The fluorinated copolymer poly (MMA–co–FMA), composed of methyl methacrylate (MMA) and 2-perfluorooctylethyl methacrylate (FMA), was prepared by emulsion polymerization using a pre-emulsified monomer addition process. The results showed that the contact angle of water on its solvent-borne film increased dramatically and reached 118o when the FMA content in the copolymer was only 0.65 mol%, approaching that of poly(2-perfluorooctylethyl methacrylate) homopolymer. Unlike the copolymer prepared by solution polymerization, X-ray photoelectron spectroscopy (XPS), and sum frequency generation (SFG) vibrational spectroscopy analysis results indicated that the fluorinated moieties in this polymer were very easily segregated at the surface of the film. The interfacial structure and properties of this polymer in solution were investigated using SFG, surface tension, and dynamic laser light scattering (DLS). It was found that emulsion polymerization produced a chain structure of the fluorinated copolymer similar to that of FMA capped PMMA, thereby providing a possible way to produce fluorinated end-capped polymers using a popular polymerization method.     

Synthesis and characterization of poly(methyl methacrylate)/polysiloxane composites and their coating properties

A series of poly(methyl methacrylate) (PMMA)/polysiloxane composites and their coatings were prepared as designed. A copolymer (PMMAVTEOS) containing methyl methacrylate (MMA) and vinyltriethoxysilane (VTEOS) was prepared by free radical polymerization and then condensed with methyl triethoxysilane (MTES) to fabricate PMMA/polysiloxane composites; their corresponding coatings were obtained via a curing process in an oven (at 75 °C). The polymers were characterized by gel permeation chromatography and Fourier transform infrared spectroscopy. The surface property, hardness, water contact angle, thermal stability, and optical property of the coatings were investigated by scanning electron microscopy, pencil hardness testing, water contact angle testing, thermogravimetric analysis, and ultraviolet–visible spectroscopy, respectively. The results showed that, after addition of MMA, the pencil hardness of the coatings was reduced from 6H to 2H and the thermal stability decreased from 365 to 314 °C. However, it increased the flexibility and adhesion properties (the water contact angle increased from 94.7° to 102.1°). The transparent PMMA/polysiloxane coatings showed excellent scratch resistance, a smooth surface, high thermal stability, and a strong adhesion property. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46358.     

POSS增强PMMA热性能和力学性能研究

采用溶液共混法将笼形纳米粒子甲基丙烯酸甲酯基多面低聚倍半硅氧烷（MMA-POSS）与聚甲基丙烯酸甲酯（PMMA）共混制备无机/有机纳米复合材料。利用傅里叶红外光谱仪、核磁共振波谱仪和场发射扫描电子显微镜对材料进行了结构表征。场发射扫描电子显微镜观察复合物薄膜表面形态显示,当MMA-POSS含量较小时,薄膜表面均匀平整,MMA-POSS均匀地分散于PMMA基体中,复合材料的热稳定性和力学性能得到明显改善,其玻璃化转变温度（Tg）和热分解温度（Td）显著提高,POSS含量为1.0 %（质量分数,下同）时,Tg 和Td分别提高了16.9 ℃和21.0 ℃。     

Compositional effects on the fouling resistance of fluorourethane coatings

Conclusions  A series of fluorinated polyurethane polymers have been prepared and characterized. Immersion experiments have been performed to determine the fouling-release effectiveness of the coatings. The surface energies of the films are between 12 mJ m⁻² to 33 mJ m⁻² and are controlled by the fluorine content of the polymer. These surface energies are well below the values shown by conventional alkyd, epoxy, vinyl, polyester, and polyurethane coatings (39 mJ m⁻² and 50 mJ m⁻²). Surface energy is not the dominant factor in determining the fouling- release behaviour of these coatings. Instead, measurements of the coating modulus, hardness, and glass transition temperature indicate that supple, soft polymers, with a high degree of mobility may display more effective fouling-release characteristics than more rigid, harder polymers below their glass transition temperatures. Surface roughness also appears to be a major factor in determining coating fouling-release behaviour. This work has demonstrated that marine organisms bind to fluorinated polyurethanes with significantly less strength than to the unfluorinated epoxy, vinyl and urethane resins which are now used with toxicants in marine coatings. However, this work has shown that these fluorinated polyurethanes are not sufficiently promising to merit further attention as non-toxic anti-fouling coatings for ship hulls. Fluorinated polyurethanes remain very attractive coatings for exterior and anti-corrosive service, especially in application requiring easy cleanability and resistance to sunlight, weather, and chemicals.     

Synthesis of Some Fluorinated Phenylmethylsiloxane Polymers and Characterization of Their Surface Properties

Conditions have been established for the preparation of three fluorinated phenylmethylsiloxane polymers via syntheses of the appropriate monomers, controlled hydrolyses of these monomers, and polymerization of the resulting oligomers. The polymers thus prepared, in increasing order of fluorine content, were poly(4-fluorophenylmethylsiloxane), poly(3,5-difluorophenylmethylsiloxane), and poly[3,5-bis(trifluoromethyl)phenylmethylsiloxane]. The surface energies of the first two polymers were measured and found to be very similar to those of typical fluorosubstituted polymers that are aliphatic rather than aromatic. This similarity indicates that the bulky phenyl groups do not significantly interfere with migration of the fluorine atoms to the surfaces of these fluorinated phenylmethylsiloxane polymers.     

Combined soft lithographic transfer‐printing and patterning method of highly fluorinated polymers as a facile surface treatment protocol

A combined soft lithographic transfer‐printing and patterning method of highly fluorinated polymers was investigated aiming to establish a facile surface treatment protocol for various substrates. Spin‐coated layers of poly(1H,1H,2H,2H‐perfluorodecyl methacrylate) (PFDMA) on patterned polydimethylsiloxane (PDMS) molds were transfer‐printed successfully on silicon, glass, aluminum substrates, resulting in the well‐controlled production of nano to micrometer‐scale periodic structures. With careful optimization of the dimension and density of the PFDMA patterns, it was possible to achieve a water contact angle as high as 175° on the transfer‐printed highly fluorinated polymer film. One of the advantages of the transfer‐patterning method is that highly fluorinated polymer films can be printed on curved surfaces while retaining their superhydrophobic and corrosion‐prevention character. In addition, the transfer‐printed PFDMA layers on the glass plates showed enhanced light transmission, which led to the extraction of 10% more light when they were applied to the emitting side of green organic light‐emitting devices. The micro‐patterned PFDMA surfaces also exhibited a significantly reduced level of bacterial adhesion when they were incubated in human bile juice. These results strongly suggest that the proposed facile transfer‐patterning protocol of highly fluorinated polymer films can be a suitable surface‐treatment technique for implantable electronic devices that exhibit improved device performance and anti‐biofouling nature. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45184.     

Characterization of optical,thermal and electrical properties of SWCNTs/PMMA nanocomposite films

The optical, thermal and electrical behavior of single-wall carbon nanotubes (SWCNTs)/poly(methyl methacrylate) (PMMA) composite are studied as a function of SWCNTs concentration. The nanocomposites were prepared in the form of films by solution casting technique. The concentrations of SWCNTs in SWCNTs/PMMA films were 0, 0.5, 1, 1.5, 2, 3.5, 5, 7.5, and 10 wt%. High-resolution transmission electron microscopy showed that SWCNTs doped in PMMA is less fragmented as compared to the powder SWCNTs. This is due to the interactions with polymers as well as the fabrication method. X-ray diffraction patterns of SWCNTs/PMMA composite films indicated that there is no covalent interaction between SWCNTs and PMMA. In addition, it demonstrates a homogeneous dispersion of SWCNTs in PMMA matrix. The optical properties of SWCNTs/PMMA films of SWCNTs concentration from 0 to 2.0 wt% have shown that the absorption intensity of the composite was enhanced ≈8.5 times as compared to the plain PMMA. Photoacoustic spectroscopy technique was used as a powerful and non-destructive tool to determine the thermal diffusivity (α), thermal effusivity (e) and thermal conductivity (k). The composites exhibited ≈160 % improvement in k at 2.0 wt%. Furthermore, the DC electrical conductivity measurements of SWCNTs/PMMA showed that the percolation threshold value was about 2.0 wt% of SWCNTs loading.     

Surface enrichment of polypropylene-graft-poly(methyl methacrylate) on polypropylene

To overcome disadvantage of polypropylene induced by its low surface energy, poly(methyl methacrylate) was grafted onto polypropylene and entrapped into polypropylene as macromolecular surface modifier. The effects of copolymer structures, contact dies and content of modifiers on their surface enrichment were studied by attenuated total reflection infrared spectroscopy (ATR-FTIR), contact angle measurements (CDA) and scanning electron microscopy (SEM). Lower content and higher surface energy dies were in favor of the copolymer to enrich on the PP surface. PPw-g-PMMA with low PMMA graft density, long length of PMMA was distributed in PP with smaller phase domains and concentration gradient, especially at lower loadings in blends, which favored its selective enrichment on the surface of PP. The modified material exhibited excellent solvent-resistance. The results indicated that PPw-g-PMMA can transfer to the surface of blends and effectively increase the hydrophilicity of PP, which offer a convenient technique to functionalize the surface of polymers with lasting-effectiveness compared with modification by homopolymers.     

Synthesis,characterization, and mechanical property of poly(urethane‐glycidyl methacrylate‐methyl methacrylate) hybrid polymers

Hybrid particles of polyurethane (PU) containing a number of small poly(methyl methacrylate) (PMMA) nanoparticles inside were prepared using glycidyl methacrylate (GMA) monomer as a linker between PU and PMMA; the resulting polymers were poly (urethane‐glycidyl methacrylate‐methyl methacrylate) (PUGM). It was found that the average particle size (D_p) of the PU particles decreased by the inclusion of PMMA particles possibly owing to the low‐solution viscosity of PU. However, D_p of the PUGM hybrid particles increased with increasing the number of covalent bonds between PMMA and PU, which might be due to decreasing the amount of ionic groups per PU chain. Subsequently, the tensile properties of the films made of the PUGM hybrid particles were investigated. It was observed that the modulus of the PU films increased upon the addition of PMMA particle because of a filler effect. In addition, it was seen that the modulus of PUGM hybrid films increased further with increasing the number of covalent bonds. This was attributed to “restricted mobility” of PU chains anchored to the PMMA particles. It was also observed that the tensile strength changed only slightly for PUGM particles, suggesting that the PU matrix was probably responsible for the necking behavior of the films. The elongation of the samples was found to depend on both the presence of covalent bonds between the PMMA particles and PU matrix and the reduced mobility of the PU chains anchored to PMMA particles. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Rim instability in polymethylmethacrylate films on self-assembled monolayers with the hydrophilicity

The solvent-induced dewetting of polymethylmethacrylate (PMMA) films prepared on self-assembled monolayers (SAMs) supported by Si substrates was investigated with the hydrophilicity of the SAMs. Dewetting of the PMMA film was characterized as a function of the surface energy of the SAMs. At lower surface energies, the rim instability was found to be of type B. Type B instability created undulations in the rims of holes. As the holes merged, fingers and then droplets formed. At higher surface energies, the rim instability of the PMMA films was of type A. Type A instability did not form fingers. The formation of PMMA droplets was dominated by the total spreading coefficient (S) of the PMMA film on the SAMs, which can be expressed as the sum of the dispersion (S^d) and the polar components (S^p) of the spreading coefficient. S^d of the PMMA films decreased, whereas S^p increased as ultraviolet (UV) irradiation for periods of time between 0 s and 100 s, respectively. This result suggests that S^d destabilized but S^p stabilized the PMMA films.     

Polyhedral oligomeric silsesquioxane-reinforced polyurethane acrylate

Hybride nanocomposite films of polyhedral oligomeric silsesquioxane (POSS) and polyurethane acrylate (PUA) were prepared by introducing POSS into PUA by free-radical photopolymerization, to enhance thermo-mechanical properties of PUA. The addition of POSS to PUA resulted in increases in the following properties: elasticity, glass transition temperature, thermal stability and dimensional stability. With increasing POSS content, the elastic modulus and thermal stability of PUA films increased due to an increased crosslinking density and the reinforcing effect of POSS particles on the PUA, whereas the surface free energies of these films decreased. The water contact angle against water increased due to the enhancement of the hydrophobicity of the polymer surface, caused by the low surface energy of POSS molecular. However, at high POSS content the mechanical properties of the films were decreased, as a result of aggregation of the POSS particles.     

Effect of crosslinking on the surface free energy and surface reorganization of waterborne fluorinated polyurethane

To endow waterborne fluorinated polyurethanes (WFPUs), films with stable lower surface free energy and lower surface reorganization after the films contacted with water, a series of crosslinked WFPUs (CWFPUs) emulsions were prepared by adjusting the content of aziridine (AZ). The effect of crosslinking on the surface free energy, glass-transition temperature (T _g), water absorption, and surface composition of dry/hydrated WFPUs and CWFPUs films were studied by CAs test, dynamic mechanical analysis, water absorption measurements, and X-ray photoelectron spectroscopy. When the fluorine content was 0.5%, the surface free energy of the CWFPUs films modified by 0.4% AZ content (CWFPU-6-0.5-CK0.4) reached to the lowest value of 15.76 mN m⁻¹ which almost equaled to the surface free energy (15.45 mN m⁻¹) of the dry uncrosslinked films (WFPU-6-0.5). With the increasing of AZ content, the T _{g, hard} of hard segments of the CWFPUs films increased and the water absorption of the CWFPUs films decreased, which suggested the formation of the crosslinked network structures. The studies of the surface elements and groups composition of dry/hydrated WFPUs and CWFPUs both confirmed that the surface reorganization and the migration of fluorinated side chains were restricted by the crosslinked network structures. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47167.     

Preparation of partially fluorinated aryl/alkyl vinylene ether polymers

A new class of partially fluorinated alternating aryl/alkyl vinylene ether (FAVE) polymers were prepared from addition polymerization of aryl trifluorovinyl ethers (TFVEs) with 1,4‐butanediol or 4‐hydroxybenzyl alcohol. Monodisperse FAVE telechelic polymers were also prepared possessing latent thermal reactivity which afforded chain‐extended perfluorocyclobutyl (PFCB) aryl ethers via step‐growth [2 + 2] cyclodimerization of the aryl TFVEs. Both linear and PFCB chain‐extended FAVE polymers produced thermally robust, optically transparent, flexible spin‐cast films. The FAVE polymers and their telechelic polymers were characterized using ¹⁹F NMR and ¹H NMR complemented with molecular weight analysis using gel permeation chromatography and thermal analysis employing differential scanning calorimetry and thermogravimetry. © 2013 Society of Chemical Industry     

Slip behavior in polymethylmethacrylate films in dependence of self-assembled monolayer wettability

The slip behavior of polymethylmethacrylate (PMMA) films prepared on self-assembled monolayers (SAM) supported by Si substrate was investigated according to the wettability of the SAM. To this end, the dewetting of thermally annealed PMMA films was measured varying the surface energies of underlyed SAM. Total surface energy (γ^t) of SAM increased with increasing UV exposure time. At surface energy of <31.3 mJ/m², the PMMA films showed slip behavior; radius of holes (R) ∝ t^0.68−0.72, where t is dewetting time. The slip behavior seems to be dominated by the viscous friction between the PMMA films and the SAM. As t increased, slip behavior disappeared, R ∝ t^0.34−0.39. At surface energy of >42.0 mJ/m², the PMMA films did not show slip behavior, R ∝ t^0.45. It means that interface effects between PMMA films and SAM layers increase with increasing of γ of SAM layers, and then the molecular interaction in the PMMA films increases. The spreading coefficient (S) of the PMMA films approached positive number for UV exposure times between 0 s and 300 s. We concluded that the stability of the PMMA films can be simply controlled by UV-ozone treatment on the SAM layers.     

Synthesis, characterization, and properties of a novel acrylic terpolymer with pendant perfluoropolyether segments

A novel acrylic terpolymer with pendant perfluoropolyether (PFPE) segments has been synthesized and fully characterized. By hexamethylene diisocyanate functional groups PFPE monofunctional macromonomers have been grafted on a poly(butyl methacrylate-co-hydroxyethyl acrylate-co-ethyl acrylate) random terpolymer. Such grafted copolymer behaves like an interface-active material, since the perfluoropolyether segments in solvent cast films rearrange themselves at the air-polymer interface by surface segregation. In addition, blends of the above graft copolymer with acrylic base polymers (either the terpolymer itself or a commercial copolymer) have been examined in terms of surface segregation and fluorine enrichment of the external layers.The critical surface tension, γ_c, of solid films made of the neat graft copolymer as well as of the polymer blend has been evaluated by contact angle measurements and Zisman plots. Even a small addition (5 wt%) of the fluorinated copolymer to the acrylic component has been found very effective in lowering the surface tension. The outermost surface composition has been investigated by XPS technique, confirming the strong fluorine enrichment. Furthermore, SEM and EDX analyses have been performed on cross-sectioned films, showing that in the above polymer blends macrophase surface segregation has originated a thick layer made of fluorinated copolymer close to the air-polymer interface.     

Fluorinated acrylic polymers: Surface properties and XPS investigations

A series of polymers based on methylmethacrylate, butylacrylate, and ω‐perfluorooctylalkylacrylate were prepared by radical polymerization. By changing both the length of the hydrocarbon spacer, between the fluorinated chain and the ester function of the fluorinated monomer, and its concentration, the surface properties of the resulting terpolymers were greatly influenced. Polymers containing small amounts of fluorinated comonomer units had considerably reduced surface energies compared to the copolymer poly (methylmethacrylate‐co‐butylacrylate) taken as reference. The outermost surface composition has been investigated by the XPS technique, confirming the strong fluorine enrichment. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 821–827, 2006     

Characterization and gamma radiation effects on poly(methyl methacrylate) doped with some benzylidene polymers

Anionic solution polmerization studies of benzylidene malononitrile, benzylidene ethyl cyanoacetate and their para chloro derivtives in dimethyl formamide (DMF) as a reaction medium using pipridene as initiator under nitrogen atmosphere at 100 °C were carried out. Infrared, ¹H NMR and ultraviolet-visible (UV-Vis) spectroscopic studies for the obtained polymers were investigated. The effect of γ-irradiation on PMMA films doped with 1 % of the benzylidene polymers was investigated by uv-vis spectroscopy. A change in the intensity of absorption bands with increasing irradiation dose was recorded. It is suggested that PMMA films doped with this type of benzylidene polymer can be used as dosimeter.