Fluorine-containing Copolymers Research Articles

Research on a fluorine-containing asphaltene dispersant and its application in improving the fluidity of heavy oil

The high viscosity characteristics of heavy oil make it difficult to extract, transport and process. Therefore, enhancing the fluidity of heavy oil can effectively improve the economic benefits of heavy oil resource development. Aggregation and precipitation of asphaltenes are the main causes of high viscosity of heavy oil. Asphaltene molecules are able to self-associate by intermolecular forces such as hydrogen bonding and π-π interactions, resulting in the formation of supramolecular aggregates with large particle size, leading to the increasing of viscosity of heavy oil. Fluorine is the most electronegative element and has a strong ability to form hydrogen bonds. This is due to the special role of the element fluorine, including high electronegativity and small atomic radius. In this study, the fluorine-containing copolymer was synthesized and used to disperse asphaltenes. This copolymer was also used for viscosity reduction on heavy oil in a block in Xinjiang, and the viscosity reduction rate (VRR) reached 70.25% at 600 ppm. Possible mechanism of asphaltene dispersion was proposed by fluorescence microscopy, X-ray diffractometry (XRD), scanning electron microscope (SEM), atomic force microscope (AFM) and transmission electron microscopy (TEM). The mechanism of interaction between copolymer and asphaltene by hydrogen bonds was further analyzed by infrared spectroscopy.

A novel Janus fabric with stable amphibious directional oil transport function

Directional oil transport (DOT) in porous matrices shows broad application potential in microfluidics, oil–water separation, and “smart” textiles. The existing DOT materials work only in either air (dry state) or underwater environments. It remains a significant challenge to develop materials with DOT capability in both air and water medium. This study prepares a novel Janus fabric with amphibious DOT property in both air (dry) and underwater environments. The DOT fabric is prepared by a dip-coating method to apply glycerol propoxylate triglycidyl ether and octadecylamine onto a fabric substrate and subsequently electrosprayed with a fluorine-containing copolymer containing both oleophobic and hydrophilic groups onto one side of the fabric. The developed Janus fabrics show stable superamphiphilicity (both hydrophilicity and oleophilicity) on the non-electrosprayed side and hydrophilicity-oleophobicity on the electrosprayed side. The opposite oleophilicity and oleophobicity feature on the two sides endows the Janus fabric with amphibious DOT property to oils with surface tension in the range of 24–32 mN/m. Without any pre-treatment, the fabric can spontaneously guide oil to transport directionally from the oleophobic side to the oleophilic side but prevent the oil from transporting in the opposite direction. This DOT property is durable and can withstand numerous harsh treatments, e.g. repeated washing and abrasion, long time storage, ultrasonication, strong acid and base attacks. To our knowledge, this is the first report of amphibious directional oil transport Janus fabric. The unique amphibious air–water DOT property enables the Janus fabric to be used for water/oil separation and underwater oil collection. Such a novel fabric may have many potential applications, such as microfluidic valves and oil–water separators. The results from this work can be extended to develop an oleophilic/oleophobic diode.

Self‐Healable Fluorinated Copolymers Governed by Dipolar Interactions

Although dipolar forces between copolymer chains are relatively weak, they result in ubiquitous inter‐ and/or intramolecular interactions which are particularly critical in achieving the mechanical integrity of polymeric materials. In this study, a route is developed to obtain self‐healable properties in thermoplastic copolymers that rely on noncovalent dipolar interactions present in essentially all macromolecules and particularly fluorine‐containing copolymers. The combination of dipolar interactions between C─F and C═O bonds as well as CH2/CH3 entities facilitates self‐healing without external intervention. The presence of dipole‐dipole, dipole‐induced dipole, and induced‐dipole induced dipole interactions leads to a viscoelastic response that controls macroscopic autonomous multicycle self‐healing of fluorinated copolymers under ambient conditions. Energetically favorable dipolar forces attributed to monomer sequence and monomer molar ratios induces desirable copolymer tacticities, enabling entropic energy recovery stored during mechanical damage. The use of dipolar forces instead of chemical or physical modifications not only eliminates additional alternations enabling multiple damage‐repair cycles but also provides further opportunity for designing self‐healable commodity thermoplastics. These materials may offer numerous applications, ranging from the use in electronics, ion batteries, H2 fuel dispense hoses to self‐healable pet toys, packaging, paints and coatings, and many others.

External surfactant-free waterborne polyurethane grafted fluorine-containing acrylic copolymer with high hardness and low water absorption using chlorinated soybean oil-based urethane acrylate as polyol

In this work, a novel soybean oil-based urethane acrylate polyol called ADSO was synthesized by the condensation reaction of hydroxyethyl acrylate modified isophorone diisocyanate with chlorinated soybean oil (SOL). The soybean oil-based waterborne polyurethane called ADSO-WPU was prepared with SOL and ADSO as polyols. Using the carbon-carbon double bonds of ADSO-WPU as reaction sites, methyl methacrylate (MMA), butyl methacrylate (BA) and 2-(perfluorohexyl)ethyl methacrylate (PFOMA) were grafting copolymerized to obtain the soybean oil-based waterborne polyurethane grafted fluorine-containing acrylate (ADSO-PUA). The results of Fourier transform infrared spectrometer, dynamic light scattering analyzer and transmission electron microscopy showed that the grafted copolymer latex was successfully prepared with particle size of about 100–300 nm. Furthermore, effects of the ratio of PFOMA, MMA and BA on properties of grafted copolymer films were studied. Compared with ADSO-WPU film, ADSO-PUA film had significantly lower water absorption, higher hardness, better mechanical properties and higher thermal stability. With the increase of PFOMA content, the water absorption rate decreased from 108% to about 10%, the hardness increased from 4H to 6H, and the tensile strength increased from 3.05 MPa to 9.79 MPa.

MANUFACTURING OF FULL REMOVABLE LAMINAR DENTURES USING DIFFERENT GROUPS OF MATERIALS FOR DENTURE BASES AND THEIR COMPARATIVE CHARACTERISTICS

Restoration of complete maxillary or mandibular adentia, despite the advances of dentistry nowadays, has always been and is still remaining one of the most challenging among the clinical issues of orthopedic dentistry. The effectiveness of a high-quality complete removable denture is largely predetermined by the properties of the denture base material. However, long experience in manufacturing the dentures has revealed a number of their disadvantages. The development of new denture base materials and their studies have been being carried out for many years. The aim of this work was to investigate the effectiveness of thermoplastic base material "Vertex ThermoSense" (Netherlands) and fluorine-containing acrylic plastic "Ftoraks" (Ukraine) used in manufacturing the dentures for edentulous patients who previously worn full removable dentures made of acrylic plastic over the past 3- 5 years. We examined and treated 43 patients with complete anodontia who went to the orthodontic clinic to order a new denture. We used fluorine-containing acrylic co-polymers "Ftorax" (Ukraine) and polyamide (nylon) "Vertex ThermoSense" (Netherlands), recommended by manufacturers for making removable dentures. We assessed the level subjective satisfaction with new dentures in different follow-up time intervals, checked the restoration of the chewing function in the patients using electromyographic techniques. Clinical findings obtained supported the superiority of Vertex ThermoSense thermoplastic material over fluorine-containing acrylic resins in terms of high functional quality and strength that facilitate the durability of these complete dentures. In addition, the denture base made of "Vertex ThermoSense" does not contain residual monomer, thereby preventing the occurrence of allergic reactions. The results of our work allow us to strongly recommend the material "Vertex ThermoSense" to implement into prosthodontic practice for manufacturing complete removable dentures.

RESULTS OF TREATMENT OF EDENTULOUS PATIENTS WITH DENTURES MADE OF «FTORAX»

Background. The problem of providing high-quality dental care to edentulous patients remains one of the most important and unresolved to this day in the clinic of prosthodontics. The causes of complete loss of teeth can be both periodontal tissue diseases and diseases of hard tooth tissues of carious and non-carious origin, trauma and the like. It becomes necessary to fabricate complete removable dentures to prevent the occurrence of pathologies in such situations. Complete secondary adentia leads to a large number of local and general complications. The chewing apparatus undergoes a number of functional and morphological changes. Therefore, the complete absence of teeth sets the dentist the task of restoring the functions of full chewing, the appearance of the patient, and speech. The complexity of high-quality prosthetics for edentulous patients is also because the clinical characteristics of supporting tissues are diverse, constantly changing, so a personal approach to creating stable denture is needed. It should be added that the fabrication of high-quality complete removable dentures largely depends on the properties of the base material. The main group of materials for the fabrication of such dentures is acrylic plastics.
 The aim. The work is focused on the study of the functional state of the masticatory muscles and the restoration of masticatory effectiveness in edentulous patients, for whom dentures were made in the prosthodontics clinic from the acrylic base material «Ftorax».
 Material and methods. Hot curing plastic based on fluorine-containing acrylic copolymers «Ftorax» was used in the work. Our evaluation of the quality of all constructions was carried out using the «BOFSAS» test, determining the biopotentials of the masticatory muscles using electromyography, and determining the masticatory effectiveness according to I.S. Rubinov.
 Results. Based on our work, it can be noted that the use of the basic acrylic material «Ftorax» allows us to achieve good fixation and stabilization of complete removable dentures, which is subjectively confirmed by the «BOFSAS» test, objectively – by the electromyographic studies and time indices during chewing test according to I.S. Rubinov.
 The amplitude during volitional compression is 556.90±8.72 μV, which approaches the norm (641.58±10.01 μV), and almost four times higher than before prosthetics (188.11±8,13 μV) after 1 year of constructions using. A similar pattern is observed with arbitrary chewing: the amplitude (547.32±8.43 μV) approaches normal (643.92±9.11 μV) compared with the results before prosthetics (201.40±9.39 μV). As for the coefficient «K», its value decreased almost twofold compared with the results before prosthetics (2.44±0.14) and equals to 1.25±0.03, which is significantly closer to normal (1,02±0.01).
 After the test by Rubinov the following results were obtained: the average time that patients with intact dentitions spent chewing on the stimulus was approximately 12.97±0.13 seconds and the average time for patients before prosthetics (with old dentures) was approximately 45.16±0,41 sec.
 The time that patients spent chewing a nut after 1 month was 28.97±0.42 seconds, after 6 months – 26.94±0.44 seconds, and after 1 year of using the entures – 25.48±0.45 sec.
 Based on this, it can be summarized that adaptation to such dentures takes place at the appropriate time with minor corrections.
 Conclusion. The results of our clinical study indicate the feasibility of using «Ftorax» in prosthodontics clinic for treatment of edentulous patients.

In situ construction of chemically heterogeneous hydrogel surfaces toward near-zero-flux-decline membranes for oil-water separation

Construction of zero-flux-decline membrane surfaces with superior antifouling properties is in great demand for the treatment of oil-water mixture. Inspired by nature, simultaneously incorporating hydrophilic and low-surface-energy groups to form a chemically heterogeneous hydrogel surface holds great promise. In this study, membranes with heterogeneous hydrogel surfaces were fabricated through a one-step reaction enhanced surface segregation method. In details, we synthesized a fluorine-containing copolymer as the modifier in casting solution, and designed tannic acid (TA) aqueous solution as the coagulation bath. During non-solvent induced phase separation, TA can in situ crosslink the modifier at the water-polymer interface through hydrogen bonds, forming a heterogeneous hydrogel layer over the membrane surface. Meanwhile, the hydrophilicity of TA rendered the hydrogel underwater superoleophobic properties. The thickness and chemical composition of the hydrogel layer were facilely manipulated by varying the TA concentration. To our surprise, the unique physicochemical characteristics of heterogeneous hydrogel layer greatly fortified the antifouling mechanisms on membrane surfaces, rendering the membrane zero-flux-decline feature with a flux of 330 L m−2 h−1 at 0.05 MPa during a 60-h cross-flow filtration of five different oil-in-water emulsions.

ADHESION OF PERIODONTAL PATHOGENS TO MATERIALS USED FOR LONG-TERM TEMPORARY CROWNS

Provisional crowns are widely used in prosthodontic treatment in dentistry, and new materials for temporary crowns, including polyetheretherketone, have emerged, which have high-quality requirements for use in long-term temporary prosthetics. Of particular importance in prosthetics are the features of adhesion of pathogenic oral microflora to orthodontic structures. This study evaluated the adhesion of cariogenic and pathogenic periodontal bacterial flora and Candida species to unpolished and polished Dentokeep polyetheretherketone (PEEK), polished polymethyl methacrylate (PMMA) material (Re-Fine Acrylic), and hotcuring acrylic plastic ─ a powder-liquid type, where the powder is a suspension graft fluorine-containing copolymer, and the liquid is a mixture of acrylic monomers, and oligomers─(Sinma-M) recommended for manufacturing long-term temporary crowns. The effect of polishing or un-polishing the study material on the adhesion of various microorganisms was studied. Polishing of Dentokeep PEEK significantly influenced primary adhesion. Microbial adhesion to sample materials was studied using ultrasonic cavitation. Adhesion of microorganisms to each material was categorized as low (0–0.27), moderate (0.28–0.69), or high (0.70–1). Streptococcus sanguinis, Prevotella intermedia, and Candida albicans adhered moderately to unpolished Dentokeep PEEK, whereas Porphyromonas gingivalis and Candida krusei were highly adherent. Candida species and P. intermedia pathogenic periodontal strain moderately adhered to polished Dentokeep PEEK, whereas S. sanguinis and P. gingivalis were highly adherent. Temporary crowns require additional hygienic measures to eradicate cariogenic (acidogenic), pathogenic periodontal, and fungal microbiota and maintain the normal qualitative and quantitative composition of oral microbiocenosis during prosthodontic treatment. In conclusion, PEEK is a promising material for the manufacture of long-term temporary crowns.

Optical oxygen sensors based on microfibers formed from fluorinated copolymers

Polymeric microfibers, particularly the fluorinated copolymers’ fibers, are promising functional materials for photoelectric devices, sensing, and energy storage due to their various surface characteristics. However, to obtain the high fluorine content copolymer-based fibers with considerable uniformity is likely to be especially challenging, which seriously debilitates their applications in sensor devices. Herein, for the first time, we presented a high fluorine content platinum porphyrin-grafted poly(isobutyl methacrylate-co-dodecafluoroheptyl methacrylate) copolymers (PtTFPP-p(IBM-co-DFHMA)) microfibrous thin-films used as optical oxygen sensors. The porous thin-film frameworks were formed of uniform microfibers, which afforded an exceptional improvement in sensitivity and exhibited 584% higher sensitivity than the solid sensing film owing to the large specific surface area, porous structures and oxygen diffusion enhancement by fluorine elements. Additionally, the remarkable emission intensity-changing characteristic of the microfiber sensing film under various air pressures facilitates convenient visualization of pressure distributions on film surface. The characteristics are particularly important for the computational fluid dynamics simulations in various sensing fields such as unsteady flow visualization and unsteady pressure measurements, etc. Owing to its attractive advantages and versatile performance, fluorine-containing copolymers fibers are expected to provide a new strategy for the rational design of high performance gas sensor devices.

Effects of fluorine and silicon components on the hydrophobicity failure behavior of acrylic polyurethane coatings

Hydrocarbon acrylic copolymer was synthesized by a radical polymerization route. Fluorine-containing copolymer was prepared via a post-fluorine modification method. Hydrocarbon, fluorine-containing, silicon-containing, and fluorosilicone acrylic polyurethane coatings were prepared by curing reaction of the curing agents and mixtures of the synthesized copolymers and amino silicone, respectively. Indoor atmospheric environment, hygrothermal environment, different temperature environment, as well as xenon arc aging environment were employed to investigate the hydrophobicity failure behavior of the coatings. Chemical structure of the coatings was characterized by attenuated total reflectance Fourier transform infrared spectrum. Water contact angles of the coatings were monitored during the failure process. Thermostability of the coatings was explored by thermo gravimetric analysis. Surface morphology of the coatings was investigated by scanning electron microscopy. Elemental composition of the coating surface was analyzed by a X-ray photoelectron spectrometer. The results showed that the acrylic polyurethane coatings were prepared as expected. In addition, the modification mechanism determined the performance of the coatings in different environments. The fluorine-containing coating performed with better hydrophobicity in the indoor atmospheric environment, hygrothermal environment and low-temperature environment, but failed faster in the high temperature and xenon arc aging environments. The silicon-containing coating exhibited relatively stable hydrophobicity in the high temperature and the xenon arc aging environments. The hydrophobicity of the fluorosilicone coating fell in between that of the fluorine- and silicon-containing coatings under all of the experimental conditions. The fluorine-containing components improved the hydrophobicity of the coatings more effectively, while the silicon-containing components contributed more to the thermo and weather resistance property of the coatings.

Novel triphilic block copolymers based on poly(2-methyl-2-oxazoline)–block–poly(2-octyl-2-oxazoline) with different terminal perfluoroalkyl fragments: Synthesis and self-assembly behaviour

We report on the synthesis and solution properties of novel fluorine-containing copolymers. Our synthetic approach provides an easy way to attach a CnF2n+1 perfluorinated terminal chain to a poly(2-methyl-2-oxazoline)–block–poly(2-octyl-2-oxazoline) copolymer and to combine hydrophilic, hydrophobic and fluorophilic moieties into one segmented polymer. A series of such quasi-triblock copolymers was prepared with variation of the length of the fluorinated chain end. Using a variety of experimental methods including dynamic light scattering and transmission cryo-electron microscopy, we prove that all of the synthesized copolymers self-assemble into nanostructures in aqueous milieu. The structures and shapes of the nanostructures are controlled by the length of the perfluoroalkyl chain. Single-layer and multi-layer vesicles as well as rod-like micelles are observed in aqueous solutions. The supramolecular structures described represent a potential platform for 19F magnetic resonance imaging contrast agents.

Preparation and failure behavior of fluorine-containing acrylic polyurethane coating

Abstract A kind of fluorine-containing acrylic copolymer was synthesized via a two steps of fluorine modification route. A hydrophobic fluorine-containing acrylic polyurethane coating was prepared with the synthesized fluorine-containing acrylic copolymer and trimer of hexamethylene diisocyanate curing agent. The fluorine-containing acrylic polyurethane coating was employed as the topcoat, while a kind of epoxy coating was used as the primer. The failure behavior of the acrylic polyurethane and epoxy composite coatings in 3.5 wt.% NaCl aqueous solution and 5 wt.% salt spray environments were studied. Chemical structure of the copolymer was confirmed by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance ( 19 F NMR). Glass-transition temperature (Tg) of the copolymer was determined with differential scanning calorimetry (DSC). The surface and cross-section morphologies of the coatings before and after failure test were explored via digital microscopy and field emission scanning electron microscopy (FESEM). The electrochemical impedance spectroscopy (EIS) was employed to analyze the coating corrosion resistance during the failure process. X-ray photoelectron spectroscopy (XPS) was used to provide insights into the chemical compositions of the coating surface. The results showed that the fluorine-containing copolymer and the corresponding coating were prepared as expected. The fluorine-containing acrylic polyurethane and epoxy composite coatings failed much faster in the salt spray environment than that in the NaCl aqueous solution. The different environment resulted in different surface chemical compositions.

Synthesis, Characterization and Properties of Amphiphilic Fluorine-Containing Copolymer

Synthesis, Characterization and Properties of Amphiphilic Fluorine-Containing Copolymer

Synthesis of fluorinated monomer and formation of hydrophobic surface therefrom

A novel route was developed to prepare fluorine-containing copolymers with long side chains of perfluoroalkyl group.

Synthesis of Fluorine-Containing-Organosilicon Oligomer in Trifluoroacetic Acid as Active Medium

In the current work we synthesized statistical fluorine-containing copolymers in trifluoroacetic acid as an active medium. Also, epoxy resin compositions containing these copolymers were prepared. It was shown that the use of trifluoroacetic acid as opposed to acetic acid makes it possible to obtain the product with a higher molecular weight and compositional homogeneity.

Synthesis, characterization and bulk properties of well-defined poly(hexafluorobutyl methacrylate)-block-poly(glycidyl methacrylate) via consecutive ATRP

A well-defined fluorine-containing copolymer with pendant epoxy groups, poly(2,2,3,4,4,4-hexafluorobutyl methacrylate-block-glycidyl methacrylate) (PHFBMA-b-PGMA), was prepared by sequential atom transfer radical polymerization (ATRP). The amphiphilic copolymer PHFBMA-b-PGMA(OH) with pendant hydroxyl groups was obtained after ring-opening reaction of the epoxy groups from PGMA. The macroinitiator agent PHFBMA-Br and its copolymers were proved to be successfully synthesized by characterization of FTIR, 1H NMR and gel permeation chromatography (GPC). The chain growth experiment demonstrated that a linear first-order relationship was fitted under the conditions. In addition, the fluorinated copolymers with functional groups in the side chain could keep the contact angle and the advantages of fluoropolymers while improving the hydrophilic property. Meanwhile, TGA testing showed that the copolymers had better thermal stability than its homopolymer. TEM observation indicated that microspheres were embedded in the stable micelles when the final copolymer concentration of aqueous solution was 1wt%.

Studies of fluorinated methylacrylate copolymer on the surface of cotton fabrics

A fluorine-containing methylacrylate copolymer latex has been synthesized by emulsion polymerization and was used as a water- and oil-repellent agent to treat some pure cotton woven fabrics at different dry and curing temperature. The treated cotton fabric surfaces were investigated by attenuated total reflectance infrared analysis and angle-dependent X-ray photoelectron spectroscopy directly. The analysis results could agree with the fluorine-containing copolymer real situation on the fabrics surface much more, and could indicate, factually, surface properties of treated or modified material rather than copolymer film. It was found that fluorine elements are enriched at the air-polymer interface and fluorine content of the treated cotton fabrics surface decreases with increasing analysis depth, which depends on heating and cooling experience, such as annealing and quenching. Furthermore, the results showed that almost the same effect can be attained using this copolymer curing from 100°C to 175°C; the relatively low curing temperature is very valuable and advantageous for some fabrics which would yellow easily at higher temperatures. The water- and oil-repellency grade of treated cotton fabrics by the fluorine-containing methylacrylate copolymer latex increases with an increase on fluorine content on the surface.

A Novel Biodegradable Fluorine-Containing Copolymer Surfactant

A novel fluorine-containing copolymer surfactant was synthesized via free radical copolymerization from maleic anhydride and rapeseed oil firstly, and then followed by an esterification reaction with dodecafluoro heptanol. The reaction progresses were monitored on-line by FTIR and the copolymerization was characterized by molecular weight (GPC) analysis. Simultaneously, the surface tension and critical micelle concentration (CMC) together with the biodegradability of the fluorine-containing copolymer surfactant were investigated in detail. The results indicate that this fluorine-containing surfactant with Mw of 66000 g/ mol and Mn of 38800 g/mol shows a strong surface tension lowering ability, the CMC is 0.1 g/L, the surface tension value at the CMC (γCMC) is 22.5 mN m−1 and less than the corresponding copolymeric hydrocarbon surfactant; the evaluation of biodegradability indicates that the biological respiration curve of the fluorine-containing copolymer surfactant with concentration of 1000 mg/L is above the endogenous respiration curve; the BOD5/COD value is higher than 0.45; the COD and TOC removal ratios after 5 days of biodegradation reach 91.0 and 89.4%, respectively, showing good biodegradability and environmental-friendly feature.

Synthesis and Nanophase-Separated Morphology of a Diblock Copolymer of Polypentafluorostyrene-b-Poly(methyl methacrylate) by Atom Transfer Radical Polymerization

We synthesized a symmetric, fluorine-containing diblock copolymer of polypentafluorostyrene-b-poly(methyl methacrylate) (PPFS-b-PMMA) by atom transfer radical polymerization (ATRP). The PPFS macroinitiator was also synthesized by ATRP by using 1-phenylethyl bromide initiator. The chemical structure of the polymer was confirmed by GPC, 1H-NMR and DSC measurements. Due to the chemical dissimilarity between the PPFS and PMMA blocks, the microphase-separation was occurred during annealing at high temperature, displaying a lamellar morphology with a thickness of approximately 35 nm.

Effects of Fluorine-Containing Graft and Block Copolymer Additives on Removal Characteristics of Dilute Benzene in Water by Microphase-Separated Membranes Modified with These Additives

This paper focuses on the effects of the addition of fluorine-containing graft or block copolymer additives composed of 1H,1H,2H,2H-heptadecafluorodecyl acylate (perfluoroalkyl acylate, PFA) and poly(dimethylsiloxane) macromonomer (PDMS) or PDMS macro-azo-initiator to a microphase-separated membrane consisting of PDMS and poly(methyl methacrylate) (PMMA) on the benzene/water selectivity for an aqueous dilute benzene solution during pervaporation and the surface characteristics and structures of the surface-modified PMMA/PDMS membranes. The addition of the fluorine-containing copolymer additives, PFA-g-PDMS and PFA-b-PDMS, to a PMMA-g-PDMS membrane yielded hydrophobic surfaces at the air side of surface-modified membranes due to the localization of their additives on the air-side surface of these membranes. The addition of a small amount of the PFA-g-PDMS and PFA-b-PDMS enhanced both the benzene/water selectivity and the permeability for an aqueous dilute benzene solution during pervaporation because of the formation of their hydrophobic surfaces and the existence of the microphase-separated structures with a continuous PDMS phase in the inner of these membranes. When larger amounts of the PFA-g-PDMS and PFA-b-PDMS were added to a PMMA/PDMS, the latter additive could keep the microphase-separated structures with a continuous PDMS phase, but the former did not. The relationship between the permeation and separation characteristics for the removal of benzene from an aqueous benzene solution and the structures the PMMA-g-PDMS membranes surface-modified with PFA-g-PDMS and PFA-b-PDMS as fluorine-containing polymer additives is discussed in detail.