Surface modification of poly(ethylene terephthalate) film by coating with poly(ethylene glycol)‐grafted polystyrene

The poly(ethylene glycol) (PEG)‐grafted styrene (St) copolymer, which was formed as a nanosphere, was used as an agent to modify the surface of poly(ethylene terephthalate) (PET) film. The graft copolymer was dissolved into chloroform and coated onto the PET film by dip–coating method. The coated amount depends on the content ratios of PEG and St, the solution concentration, and the coating cycles. The graft copolymers having a low molecular weight of PEG‐ or St‐rich content was fairly stable on washing in sodium dodecyl sulfate (SDS) aqueous solution. It was confirmed that the PET surface easily altered its surface property by the coating of the graft copolymers. The contact angles of the films coated with the graft copolymers were very high (ca. 105–120°). The coated film has good antistatic electric property, which agreed with PEG content. The best condition of coating is a one‐cycle coating of 1% (w/v) graft copolymer solution. The coated surface had water‐repellency and antistatic electric property at the same time. The graft copolymer consisted of a PEG macromonomer; St was successfully coated onto PET surfaces, and the desirable properties of both of PEG macromonomer and PSt were exhibited as a novel function of the coated PE film. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1524–1530, 1999     

Functionalization of poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) films via surface‐initiated atom transfer radical polymerization: Comparison with the conventional free‐radical grafting procedure

We modified hydrophobic poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBHV) films with hydrophilic chains to control their surface properties. We designed and investigated surface‐initiated atom transfer radical polymerization (SI‐ATRP) to modify the PHBHV films by grafting poly(2‐hydroxyethyl methacrylate) (PHEMA) from the surface. This method consisted of two steps. In the first step, amino functions were formed on the surface by aminolysis; this was followed by the immobilization of an atom transfer radical polymerization initiator, 2‐bromoisobutyryl bromide. In the second step, the PHEMA chains were grafted to the substrate by a polymerization process initiated by the surface‐bound initiator. The SI‐ATRP technique was expected to favor a polymerization process with a controlled manner. The experimental results demonstrate that the grafting density was controlled by the reaction conditions in the first step. The grafted films were analyzed by Fourier transform infrared spectroscopy, contact angle testing, scanning electron microscopy, and energy‐dispersive X‐ray spectroscopy. The results show that grafted chains under the SI‐ATRP method were preferentially located on the surface for surface grafting and in the bulk for conventional free‐radical polymerization initiated by benzoyl peroxide. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Grafting polymer from poly(ethylene terephthalate) films by surface‐initiated ATRP

Surface‐initiated atom transfer radical polymerization (ATRP) from poly(ethylene terephthalate) (PET) film was studied. Poly(methyl methacrylate) (PMMA), poly (acrylamide) (PAAM), and their diblock copolymer (PMMA/PAAM) on the surface of PET film were successfully prepared by surface‐initiated ATRP. The structures and properties of the modified PET film were characterized by FT‐IR/ATR, X‐ray photoelectron spectroscopy (XPS), measurements of contact angles, and scanning electronic microscopy (SEM). The results indicate that the surface properties of PET film were greatly improved by grafted polymer. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Modification of poly(tetrafluoroethylene) and copper foil surfaces by graft polymerization for adhesion improvement

Thermal graft polymerization-induced lamination of surface-modified copper foil to surface-modified poly(tetrafluoroethylene) (PTFE) film was achieved in the presence of an epoxy resin adhesive and glycidyl methacrylate (GMA) monomer, or in the presence of GMA and hexamethylenediamine (HEDA). The copper foil surfaces were pretreated with an organosilane coupling agent (SCA), such as (3-mercaptopropyl)trimethoxysiane, 3-(trimethoxysilyl)propyl methacrylate, or N¹-[3-(trimethoxysilyl)propyl]diethylene-triamine. The silanized copper foils were subjected to brief Ar plasma treatment and subsequently to UV-induced graft polymerization with GMA (the Cu-SCA-g-GMA surface). Surface modification of PTFE film included Ar plasma treatment alone, or Ar plasma pretreatment followed by UV-induced graft polymerization with GMA (the GMA-g-PTFE surface). The modified surfaces and interfaces were characterized by X-ray photoelectron spectroscopy (XPS) and water contact angle measurements. The Cu-SCA-g-GMA/epoxy resin-GMA/PTFE or Cu-SCA-g-GMA/GMA–HEDA/GMA-g-PTFE laminates exhibited T-peel adhesion strengths in excess of 9 N/cm and the joints delaminated by cohesive failure inside the bulk of the PTFE film. The strong adhesion in these Cu foil-PTFE laminates is attributable to the fact that the GMA chains are covalently tethered on both the PTFE and the silanized Cu surfaces, as well the fact that these grafted GMA chains are covalently incorporated into the highly crosslinked network structure of the adhesive at the interphase.     

Electroless plating of copper on fluorinated polyimide films modified by surface graft copolymerization with 1‐vinylimidazole and 4‐vinylpyridine

Electroless plating of copper via a tin‐free activation process was carried out effectively on two types of fluorinated polyimide (FPI) films modified by UV‐induced surface graft copolymerization with N‐containing monomers, such as 1‐vinylimidazole (VIDz) and 4‐vinyl pyridine (4VP). The graft copolymerization of VIDz and 4VP was carried out on the argon (Ar) plasma‐pretreated FPI films via a solvent‐free process under atmospheric conditions. X‐ray photoelectron spectroscopy (XPS) results showed that the VIDz graft‐copolymerized FPI surface (the VIDz‐g‐FPI surface) and 4VP graft‐copolymerized FPI surface (the 4VP‐g‐FPI surface) were much more susceptible to the electroless deposition of metals via the Sn‐free process than the pristine FPI surfaces, and the FPI surfaces modified by Ar plasma pretreatment alone. T‐peel adhesion strengths above 9 N/cm were achieved for the electrolessly deposited copper on both VIDz‐g‐FPI surfaces (the Cu/VIDz‐g‐FPI assemblies) and 4VP‐g‐FPI surfaces (the Cu/4VP‐g‐FPI assemblies). These adhesion strength values were much higher than those obtained for assemblies involving electrolessly deposited copper on pristine or on Ar plasma pretreated FPI films. The high adhesion strength of the Cu/VIDz‐g‐FPI and Cu/4VP‐g‐FPI assemblies was attributed to the synergistic effect of spatial interactions of the grafted VIDz or 4VP polymer chains with the copper atoms, and the fact that the VIDz or 4VP polymer chains were covalently tethered on the FPI surfaces. XPS results also revealed that the Cu/VIDz‐g‐FPI and Cu/4VP‐g‐FPI assemblies delaminated by cohesive failure inside the FPI films.     

Simultaneous graft copolymerization of 2‐hydroxyethyl methacrylate and acrylic acid onto polydimethylsiloxane surfaces using a two‐step plasma treatment

Acrylic acid (AAc) and 2‐hydroxyethyl methacrylate (HEMA) mixtures were simultaneously grafted onto the surfaces of polydimethylsiloxane (PDMS) films using a two‐step oxygen plasma treatment (TSPT). The first step of this method includes: oxygen plasma pretreatment of the PDMS films, immersion in HEMA/AAc mixtures, removal from the mixtures, and drying. The second step was carried out by plasma copolymerization of preadsorbed reactive monomers on the surfaces of dried pretreated films. The effects of pretreatment and polymerization time length, monomer concentration, and ratio on peroxide formation and graft amount were studied. The films were characterized by attenuated total reflection Furrier transformer infrared (ATR‐FTIR) spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), zeta potential, surface tension, and water contact angle measurements. The ATR‐FTIR spectrum of the modified film after alkaline treatment showed the two new characteristic bands of PHEMA and PAAc. Both increase the polar part of surface tension (γ_p) after grafting and the evaluation of surface charge at pH 1.8, 7, and 12 confirmed the presence of polar groups on the surface of grafted films with a mixture of HEMA/AAc. Morphological studies using both AFM and SEM evaluation illustrated various amounts of grafted copolymer on the surface of PDMS films. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Surface modification of low‐density polyethylene films by UV‐induced graft copolymerization with a fluorescent monomer

Surface modification of argon plasma–pretreated low‐density polyethylene (LDPE) film via UV‐induced graft copolymerization with a fluorescent monomer, (pyrenyl)methyl methacrylate (Py)MMA, was carried out. The chemical composition and morphology of the (Py)MMA‐graft‐copolymerized LDPE [(Py)MMA‐g‐LDPE] surfaces were characterized, respectively, by X‐ray photoelectron spectroscopy (XPS) and by atomic force microscopy (AFM). The concentration of the surface‐grafted (Py)MMA polymer increased with Ar plasma pretreatment time and UV graft copolymerization time. The photophysical properties of the (Py)MMA‐g‐LDPE surfaces were measured by fluorescence spectroscopy. After graft copolymerization with the fluorescent monomer, the surface of the LDPE film was found to have incorporated new and unique functionalities. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1526–1534, 2001     

Novel comb‐structured‐polymer‐grafted carbon black by surface‐initiated atom transfer radical polymerization and ring‐opening polymerization

Novel comb‐structured‐polymer‐grafted carbon black (CB) was synthesized with a combination of surface‐initiated atom transfer radical polymerization and ring‐opening polymerization. First, poly(2‐hydroxyethyl methacrylate) (PHEMA) was grafted onto the CB surface by surface‐initiated atom transfer radical polymerization. The prepared CB‐g‐PHEMA contained 35.6–71.8% PHEMA, with the percentage depending on the molar ratio of the reagents and the reaction temperature. Then, with PHEMA in CB‐g‐PHEMA as the macroinitiator, poly(?‐caprolactone) (PCL) was grown from the CB‐g‐PHEMA surface by ring‐opening polymerization in the presence of stannous octoate. CB‐g‐PHEMA and CB‐g‐(PHEMA‐g‐PCL) were characterized with Fourier transform infrared, ¹H‐NMR, thermogravimetric analysis, dynamic light scattering, and transmission electron microscopy. The resultant grafted CB had a shell of PHEMA‐g‐PCL. On the whole, the CB nanoparticles were oriented in dendritic lamellae formed by these shells. This hopefully will result in applications in gas sensor materials and nanoparticle patterns. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Photo‐induced grafting of poly(ethylene glycol) onto polyamide thin film composite membranes

In this study, the surface grafting of poly(ethylene glycol) (PEG) onto commercial polyamide thin film composite (TFC‐PA) membranes was carried out, using ultraviolet photo‐induced graft polymerization method. The attenuated total reflection Fourier transform infrared spectra verify a successful grafting of PEG onto the TFC‐PA membrane surface. The scanning electron microscope and atomic force microscope analyses demonstrate the changes of the membrane surface morphology due to the formation of the PEG‐grafted layer on the top. The contact angle measurements illustrate the increased hydrophilicity of the TFC‐PA‐g‐PEG membrane surfaces, with a significantly reduced water contact angles compared to the unmodified one. Consequently, the separation performance of the PEG‐grafted membranes is highly improved, with a significant enhancement of flux at a great retention for removal of the different objects in aqueous feed solutions. In addition, the antifouling property of the modified membranes is also clearly improved, with the higher maintained flux ratios and the lower irreversible fouling factors compared to the unmodified membrane. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45454.     

Plasma‐induced solid‐state polymerization modified poly(tetrafluoroethylene) membrane for pervaporation separation of aqueous alcohol mixtures

Acrylamide (AAm) solid state polymerization was induced using argon plasma to improve the pervaporation performance of poly(tetrafluoroethylene) (PTFE) membranes (PTFE‐g‐PAAm) in aqueous alcohol mixtures. The surface morphology, chemical composition, and hydrophilicity changes in the PTFE and PTFE‐g‐PAAm membranes were investigated using ATR‐FTIR, SEM, AFM, X‐ray photoelectron spectroscopy, and water contact angle measurements. The surface hydrophilicity rapidly increased with increasing Ar exposure time, but decreased after longer Ar exposure time because of the degradation in the PTFE‐g‐PAAm membrane grafted layer. Compared with the hydrophilicity of the pristine PTFE membrane (water contact angle = 120°), the argon plasma induced acrylamide (AAm) solid‐state polymerization onto the PTFE surface (water contact angle = 43.3°) and effectively improved the hydrophilicity of the PTFE membrane. This value increases slowly with increasing aging time and then reaches a plateau value of about 50° after 10 days of storage under air. The pervaporation separation performances of the PTFE‐g‐PAAm membranes were higher than that of the pristine PTFE membrane. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:909–919, 2006     

Thermo‐Responsive Gating Characteristics of Poly(N‐isopropylacrylamide)‐Grafted Membranes

Both hydrophilic Nylon‐6 membranes and hydrophobic poly(vinylidene fluoride) (PVDF) membranes, with a wide range of grafting yields of poly(N‐isopropylacrylamide) (PNIPAM), were prepared using the plasma‐graft pore‐filling polymerization method. The effect of the physical and chemical properties of the substrates on the thermo‐responsive gating characteristics of the PNIPAM‐grafted membranes was investigated experimentally. For both the PVDF and Nylon‐6 membranes, the grafted PNIPAM polymers were found not only on the membranes outer surface, but also on the inner surfaces of the pores throughout the entire thickness of the membrane. The thermo‐responsive gating characteristics of the PNIPAM‐grafted membranes were heavily affected by the physical and chemical properties of the porous membrane substrates. The PNIPAM‐g‐Nylon‐6 membranes exhibited a much larger thermo‐responsive gating coefficient than the PNIPAM‐g‐PVDF membranes. Furthermore, to achieve the largest thermo‐responsive gating coefficient, the corresponding optimum grafting yield of PNIPAM for the PNIPAM‐g‐Nylon‐6 membranes was also larger than that for the PNIPAM‐g‐PVDF membranes.     

Poly(methyl methacrylate)‐grafted cellulose nanocrystals: One‐step synthesis,nanocomposite preparation,and characterization

Cellulose nanocrystals (CNCs) are ideal reinforcing agents for polymer nanocomposites because they are lightweight and nano‐sized with a large aspect ratio and high elastic modulus. To overcome the poor compatibility of hydrophilic CNCs in non‐polar composite matrices, we grafted poly(methyl methacrylate) (PMMA) from the surface of CNCs using an aqueous, one‐pot, free radical polymerization method with ceric ammonium nitrate as the initiator. The hybrid nanoparticles were characterized by CP/MAS NMR, X‐ray photoelectron spectroscopy, infrared spectroscopy, contact angle, thermogravimetric analysis, X‐ray diffraction, and atomic force microscopy. Spectroscopy demonstrates that 0.11 g/g (11 wt %) PMMA is grafted from the CNC surface, giving PMMA‐g‐CNCs, which are similar in size and crystallinity to unmodified CNCs but have an onset of thermal degradation 45 °C lower. Nanocomposites were prepared by compounding unmodified CNCs and PMMA‐g‐CNCs (0.0025–0.02 g/g (0.25–2 wt %) loading) with PMMA using melt mixing and wet ball milling. CNCs improved the performance of melt‐mixed nanocomposites at 0.02 g/g (2 wt %) loading compared to the PMMA control, while lower loadings of CNCs and all loadings of PMMA‐g‐CNCs did not. The difference in Young's modulus between unmodified CNC and polymer‐grafted CNC composites was generally insignificant. Overall, ball‐milled composites had inferior mechanical and rheological properties compared to melt‐mixed composites. Scanning electron microscopy showed aggregation in the samples with CNCs, but more pronounced aggregation with PMMA‐g‐CNCs. Despite improving interfacial compatibility between the nanoparticles and the matrix, the effect of PMMA‐g‐CNC aggregation and decreased thermal stability dominated the composite performance.     

Surface grafting polymerization of N‐vinyl‐2‐pyrrolidone onto a poly(ethylene terephthalate) nonwoven by plasma pretreatment and its antibacterial activities

The objective of this research was the surface grafting polymerization of biocompatible monomer N‐vinyl‐2‐pyrrolidone (NVP) onto a plasma‐treated nonwoven poly(ethylene terephthalate) (PET) substrate with ultraviolet (UV)‐induced methods. The effects of various parameters, such as the monomer concentration, reaction time, initiator (ammonium peroxodisulfate) concentration, and crosslinking agent (N,N′‐methylene bisacrylamide) concentration, on the grafting percentage were studied. The grafting efficiency of the modified nonwoven PET surfaces reached a maximum at 50 min of UV irradiation and with a 30 wt % aqueous NVP solution. After the plasma activation and/or grafting, the hydrophobic surface of the nonwoven was modified into a hydrophilic surface. NVP was successfully grafted onto nonwoven PET surfaces. The surface wettability showed that the water absorption of NVP‐grafted nonwoven PET (NVP‐g‐nonwoven PET) increased with increasing grafting time. NVP‐g‐nonwoven PET was verified by Fourier transform infrared spectra and scanning electron microscopy measurements. An antibacterial assessment using an anti‐Staphylococcus aureus test indicated that S. aureus was restrained from growing in NVP‐g‐nonwoven PET. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 803–809, 2006     

Surface modification of polysulfone membranes by low‐temperature plasma–graft poly(ethylene glycol) onto polysulfone membranes

A novel and general method of modifying hydrophobic polysulfone (PSF) to produce highly hydrophilic surfaces was developed. This method is the low‐temperature plasma technique. Graft polymer‐modified surfaces were characterized with the help of Fourier transform infrared attenuated total reflection (FTIR–ATR) and X‐ray photoelectron spectroscopy (XPS). Study results demonstrated that poly(ethylene glycol) (PEG) could be grafted onto the PSF membrane surface by low‐temperature plasma. The hydrophilic character of the modified surfaces was increased in comparison with that of the parent membrane. The contact angle for a modified PSF membrane was reduced apparently. We analyzed the effectiveness of this approach as a function of plasma operating variables including plasma treatment power and treatment time. Hence, plasma‐induced graft polymer modification of membranes can be used to adjust membrane performance by simultaneously controlling the surface hydrophilicity and hemocompatibility. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 979–985, 2000     

Crosslinked epoxy microspheres: Preparation,surface‐initiated polymerization,and use as macroporous silica porogen

In this article, we report the preparation of crosslinked epoxy microspheres with diameters of 5–10 μm prepared via phase‐inverted phase separation induced by polymerization in the thermosetting blend of epoxy and poly(ε‐caprolactone). The surfaces of the epoxy microspheres were functionalized to bear 2‐bromopropionyl groups, which were further used as initiators to obtain poly(glycidyl methacrylate) (PGMA) grafted epoxy microspheres via the surface‐initiated atom transfer radical polymerization approach. The PGMA‐grafted epoxy microspheres were then employed to react with 3‐aminopropyltrimethoxylsilane (APTMS) to obtain the functionalized epoxy microspheres, the surface of which contained a great number of trimethoxysilane groups. A co‐sol–gel process between the APTMS‐functionalized epoxy microspheres and tetraethoxysilane was performed, and organic–inorganic glassy solids were obtained. The organic–inorganic glasses were used as precursors for accessing macroporous silica materials via pyrolysis at elevated temperatures. The hierarchical porosity of the resulting macroporous silica was investigated by means of field emission scanning electronic microscopy, transmission electronic microscopy, and surface‐area Brunauer–Emmett–Teller (BET) measurements. We found that the macroporous silica possessed BET surface areas in the range 183.9–235.2 m²/g, depending on the compositions of their precursors. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Bone cell viability on collagen immobilized poly(3‐hydroxybutrate‐co‐3‐hydroxyvalerate) membrane: Effect of surface chemistry

The effect of surface chemistry on proliferation and morphology of bone cells cultured on surface modified poly(3‐hydroxybutrate‐co‐3‐hydroxyvalerate) (PHBV) and untreated PHBV was evaluated. The surface of cast PHBV film was physically and chemically immobilized with collagen. For preparing chemically immobilized collagen surface, PHBV film was ozone treated followed by grafting of PMAA chains and the immobilization of collagen. The surface roughness and hydrophilicity of PHBV film were determined by atomic force microscopy (AFM) and contact angle measurements, respectively. It was found that the duration of ozone exposure and monomer concentration used for grafting PMMA chains influenced the amount of collagen immobilized. The cell proliferation on PHBV surfaces with chemically and physically immobilized collagen was compared with untreated PHBV using 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl tetrazolium bromide (MTT) assay. The bone cell activity on chemically and physically immobilized collagen PHBV films was found to be 246 and 107% for UMR‐106 and 68 and 9% for MC3T3 cell lines, respectively. Although the results are very preliminary, the chemically grafted collagen on PHBV surface provided a favorable matrix for cell proliferation. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2445–2453, 2004     

Surface microphase separation in PDMS‐b‐PMMA‐b‐PHFBMA triblock copolymer films

Well‐defined poly(dimethylsiloxane)‐block‐poly(methyl methacrylate)‐block‐poly(2,2,3,3,4,4,4‐heptafluorobutyl methacrylate) (PDMS‐b‐PMMA‐b‐PHFBMA) triblock copolymers were synthesized via atom transfer radical polymerization (ATRP). Surface microphase separation in the PDMS‐b‐PMMA‐b‐PHFBMA triblock copolymer films was investigated. The microstructure of the block copolymers was investigated by transmission electron microscopy (TEM) and atomic force microscopy (AFM). Surface composition was studied by X‐ray photoelectron spectroscopy (XPS). The chemical composition at the surface was determined by the surface microphase separation in the PDMS‐b‐PMMA‐b‐PHFBMA triblock copolymer films. The increase of the PHFBMA content could strengthen the microphase separation behavior in the PDMS‐b‐PMMA‐b‐PHFBMA triblock copolymer films and reduce their surface tension. Comparison between the PDMS‐b‐PMMA‐b‐PHFBMA triblock copolymers and the PDMS‐b‐PHFBMA diblock copolymers showed that the introduction of the PMMA segments promote the fluorine segregation onto the surface and decrease the fluorine content in the copolymers with low surface energy. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Grafting of polystyrene and poly(p‐chlorostyrene) from the surface of ramie fiber via RAFT polymerization

Reversible addition‐fragmentation chain transfer (RAFT) radical polymerization was used for controlled grafting of styrene and p‐chlorostyrene from the surface of ramie fiber. The hydroxyl groups in ramie fiber were first converted to thiocarbonylthio groups as the RAFT chain transfer agent then used to mediate the RAFT polymerization of styrene, and p‐chlorostyrene in tetrahydrofuran using azobis (isobutyronitrile) as initiator at 60°C. The grafted copolymers were analyzed by Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetry, and contact angle measurements. The results confirmed that grafting occurred on the surface of the ramie fiber, substantially increasing the water contact angle from 75.31° to 147° for polystyrene grafted ramie fiber (cell‐PS) and 135° for poly(p‐chlorostyrene) (cell‐PSCl), and improving the hydrophobicity of the grafted fiber. The homopolymers formed in the polymerization were analyzed by size exclusion chromatography to estimate the molecular weights and polydispersity indices (PDIs) of chains grafted from the surface of the ramie fiber, as well as showed narrow chain length distributions with a PDI of 1.32–1.70. These materials possess potential applications in many advanced technologies. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effects of plasma treatment on CO2 plasticization of poly(methyl methacrylate) gas‐separation membranes

To suppress undesirable plasticization effects of condensable gas (CO₂) in high pressure gas‐separation process, a surface‐modified poly(methyl methacrylate) (PMMA) membrane prepared by a plasma treatment was synthesized in this study. The pressure dependencies of permeability were analyzed to characterize the plasticization phenomenon and how it can be controlled by the plasma modification. FTIR‐ATR and TGA results suggest that the plasma treatment leads to surface crosslinking of PMMA membrane. Thus, the plasticization effect resulting from sorbed CO₂ on the Ar‐plasma–treated PMMA membrane was significantly reduced, but the reduction in permeability was lower than that of other crosslinking modification methods. The reduction of the CO₂ permeability contributes to a major part to the selectivity of He/CO₂ for the Ar‐plasma–treated PMMA membranes. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 395–401, 2004     

Effect of miscibility on migration of third component in star‐like co‐continuous and disperse‐within‐disperse mixed brushes

Novel ternary mixed‐brush single crystals were designed with disperse‐within‐disperse and star‐like co‐continuous morphologies based on poly(ethylene glycol) (PEG)‐b‐polystyrene (PS)/PEG‐b‐poly(methyl methacrylate) (PMMA)/PEG‐b‐polyaniline (PANI) and PEG‐b‐PS/PEG‐b‐PMMA/PEG‐b‐(poly(?‐caprolactone) (PCL) or poly(l ‐lactide) (PLLA)) block copolymers, respectively. In the disperse‐within‐disperse ternary mixed brushes, PANI nanorods were dispersed within the matrix (PS)–dispersed (PMMA) amorphous brushes. The flexibility and rigidity of brushes mainly affected the ultimate morphology and arrangement of amorphous coiled brushes in the vicinity of PANI nanorods. In addition, the migration of PCL and PLLA crystallizable brushes was evident into PMMA phases dispersed in the PS matrix, leading to star‐like co‐continuous patterns of PCL and PLLA brushes. This phenomenon was related to the miscibility of crystallizable PCL and PLLA brushes with the PMMA phase. The migration of crystallizable PCL and PLLA brushes increased the size of PMMA domains in the star‐like co‐continuous patterns. Despite the larger osmotic pressure of PLLA brushes, their higher miscibility with PMMA chains reflected the greater PMMA dispersal and wider PLLA star‐like branches. © 2017 Society of Chemical Industry