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Comb-like polymers with pendant-like perfluorocarbon side chains self-assemble into smectic lamellae and have been extensively used as water-repellent, hydrophobic coating materials characterized by large water contact angles (θ > 120°). As poly(perfluorooctyl acrylate) films are “apparently hydrophobic” (θ > 120°), the interaction of such materials and water molecules has been largely overlooked. To unravel the molecular-level interactions between water and apparently hydrophobic polymers, specular and off-specular neutron scattering experiments were conducted at defined osmotic pressure ΠH2O. The poly{2-[(perfluorooctylethyl)carbamate]ethyl} acrylate (PFAUr-C8), which had a carbamate linker, transitioned to another lamellar phase at 89 °C. At T = 25 °C; the lamellar periodicity of PFAUr-C8 slightly increased with decreasing osmotic pressure, while the vertical correlation length increased. However, the poly[(perfluorooctyl)ethyl] acrylate (PFA-C8) that did not contain a carbamate linker directly transitioned to a disordered phase at 84 °C. The lamellar periodicity of PFA-C8 was largely independent of the osmotic pressure, suggesting that PFA-C8 was poorly hydrated. Remarkably, the vertical correlation length decreased with decreasing osmotic pressure. Because hydration facilitated by the linker modulated the smectic lamellae of the poly(perfluoroalkyl acrylate), water molecules could be used to optimize the self-assembly of apparently hydrophobic liquid crystalline polymers. Self-assembled smectic lamellae of comb-like polymers with pendant-like perfluorocarbon side chains have been extensively used as water-repellent, hydrophobic coating materials, which are characterized by large water contact angles (θ > 120°). By measuring off-specular neutron scattering under defined osmotic pressures, we unraveled that such “apparently hydrophobic” materials interact with water and adapt the inter-lamellar correlation. This suggested that water molecules could be used to optimize the self-assembly of hydrophobic liquid crystalline polymers.

The crystalline structures of isotactic polypropylene (iPP) thin films were investigated using grazing incident wide-angle X-ray diffraction (GIWAXD), atomic force microscopy (AFM), and transmission electron microscopy (TEM). The out-of-plane (110) reflection split with 99° inclination in the GIWAXD pattern. The film surface was covered with flat-on mother lamellae with orthogonal daughter lamellae. The cross-sectional TEM image and the fast Fourier transform-processed image showed vertically aligned daughter lamellae and cross-hatched lateral mother lamellae. Flat-on lamellae may be preferentially produced at the substrate interface, after which the mother lamellae may yield daughter lamellae from the ac plane to give vertically aligned lamellae. The daughter lamellae yield in-plane lamellae with flat-on alignment from the ac plane, resulting in the global growth of a cross-hatched lamellar structure. Grazing incidence wide-angle X-ray diffraction study of lamellar orientation in isotactic polypropylene thin films. Crystalline structure of isotactic polypropylene (iPP) thin films was investigated by means of grazing incident wide-angle X-ray diffraction, atomic force microscopy, and transmission electron microscopy. Flat-on mother lamellae with orthogonal daughter lamellae form in the thin film. We propose a lamellar growth model for iPP thin films in which the crystallization progresses flat-on mother lamellae at the substrate interface to out-of-plane growth of daughter lamellae from the mother lamellae.

Thermal behavior, molecular aggregation structure, and water repellency for poly{2-[(perfluorooctylethyl)carbamate]ethyl}acrylate (PFAUr-C8) were studied by differential scanning calorimetry (DSC), polarized optical microscopy (POM), wide-angle X-ray diffraction (WAXD), grazing-incidence wide-angle X-ray diffraction (GI-WAXD), contact angle measurements, and X-ray photoelectron spectroscopy (XPS). The impact of the carbamate linker was verified by comparison with poly[2-(perfluorooctyl)ethyl]acrylate (PFA-C8). PFAUr-C8 exhibited two phase transitions at 357 K and 416 K, whereas PFA-C8 showed a single-phase transition at 347 K. Both PFAUr-C8 and PFA-C8 formed a bilayered hexatic smectic-B phase at room temperature. Although the lamellar structure for the fluoroalkyl (Rf) groups was immediately lost in PFA-C8 after disordering of the lateral translational order, PFAUr-C8 maintained a stacked lamellar structure without lateral translational order. PFAUr-C8 exhibited excellent water repellency at room temperature similar to PFA-C8. The outstanding thermal stability of the lamellar structure in PFAUr-C8 is attributed to the cohesive interaction of the carbamate linkage. Thermal behavior, molecular aggregation structure, and water repellency of a comb-shaped fluoropolymer, poly{2-[(perfluorooctylethyl)carbamate]ethyl}acrylate (PFAUr-C8), were investigated. PFAUr-C8 exhibited polymorphic ordered structures, where the stacked lamellar structure of Rf side chains was maintained without their lateral translational order. The cohesive dipolar interactions in the carbamate linkers would induce the thermal stability of the lamellar structure. PFAUr-C8 exhibits superior water repellency.

Random copolymers (P(M100-m/T m )) composed of 2-methacryloyloxyethyl phosphorylcholine (MPC), which suppresses protein adsorption, and 3-(triethoxysilyl)propyl methacrylate (MTEOS), which can be covalently fixed on a glass surface, were prepared via photoinitiated radical polymerization. When P(M100-m/T m ) was coated on a glass surface, a protein antifouling effect could be observed because of the presence of MPC units on the glass surface. To confirm the coating of the glass surface with P(M100-m/T m ) by fluorescence microscopy, pyrene-labeled P(M100-m/T m ) was also prepared. An ethanol solution of P(M100-m/T m ) was spin-coated on the glass, which was exposed to NH3 vapor to promote the reaction of the pendant triethoxysilyl groups in P(M100-m/T m ) with silanol groups on the glass. The coating of the glass with MPC was confirmed by fluorescence microscopy. The protein antifouling effects of the P(M100-m/T m )-coated glass were confirmed using fluorescence-labeled proteins. It is expected that P(M100-m/T m ) can be applied as a surface-coating agent on glass containers for protein formulations. Random copolymers (P(M100-m/T m )) composed of 2-methacryloyloxyethyl phosphorylcholine, which suppresses protein fouling, and 3-(triethoxysilyl)propyl methacrylate, which can react covalently to the glass surface, were prepared via photoinitiated radical polymerization. Coating of the glass with P(M100-m/T m ) was confirmed by red fluorescence from Rhodamine 6G. The protein antifouling properties of the P(M100-m/T m ) coating on glass were confirmed using fluorescence-labeled proteins.

Direct surface modification of polymer fibers and films by surface-initiated polymerization has been investigated. The introduction of initiating sites on polymer materials and their successive polymerization produce surface-tethered polymer chains on the polymer surface. The surface-selective modification controls the surface properties, such as wetting, lubrication and anti-fouling, without sacrificing bulk performance. Among the various procedures for introduction of initiating groups and subsequent polymerization proposed to date, this focused review article highlights our studies on polymer brush grafting to electrospun polymer fibers and polymer films through surface-initiated polymerization. We review studies focusing on grafting polymer chains to five different types of solid polymers: poly(methyl methacrylate)-based copolymers, Br-containing polyolefins, poly(vinylidene fluoride-co-trifluoroethylene), poly(butylene terephthalate), and poly(ether-ether ketone). Direct surface modification of polymer fibers and films by surface-initiated polymerizations has been investigated. The introduction of initiating sites on the polymer materials and successive polymerization produce surface-tethered polymer chains on the polymer surface. The surface-selective modification controls the surface properties such as wetting, lubrication and anti-fouling without sacrificing the bulk performances. Researches on grafting polymer chains to five types of polymers, poly(methyl methacrylate)-based copolymer, Br-containing polyolefins, poly(butylene terephthalate), poly(vinylidene fluoride-co-trifluoroethylene) and poly(ether-ether ketone) are reviewed.

Nature-inspired material design concepts and recent progress on anti-fouling polymer materials are reviewed, and our recent researches on anti-fouling studies with polymer brushes are summarized. Zwitterionic polyelectrolyte brush immobilized surfaces represent significant anti-fouling for bio-macromolecules, oil foulants, marine fouling organisms and pipeline foulants. The anti-fouling mechanism was considered on the basis of the wetting, lubrication, hydrated chain dimension and hydrogen-bonding structure of hydrated water in the polyelectrolyte brushes.

The anti-fouling character of polymer brushes against marine organisms was investigated by performing settlement tests with barnacle cypris larvae and mussel larvae in their adhesion period, as well as a marine bacteria colonization test. The surface charge and hydration state in saline seawater appear to be important factors in the versatile anti-fouling performance of zwitterionic polyelectrolyte brushes.

The effectiveness of energy-resolved (ER) X-ray photoelectron spectroscopy (XPS) with synchrotron radiation (SR) soft X-ray source for analysis of the outermost chemical composition of polymer materials is demonstrated. The surface molecular aggregation state of poly(ethylene glycol) (PEG)/poly(perfluorooctylethyl acrylate) (PFA-C8) was confirmed using ER-XPS. The XPS with SR soft X-ray source detect only the single bilayer structure of the PFA-C8 component, whereas the XPS with Mg Kα X-ray source detect both the PFA-C8 component at the outermost surface and PEG component at the interior.

Halloysite nanotubes (HNTs) modified by a chemical vapor adsorption (CVA) process remarkably improve the thermal stability of polycarbonate nanocomposites. HNTs were modified with N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (AEAPS) and n-octadecyltrimethoxysilane (OTMS) using a CVA process. Both Fourier-transform infrared spectroscopy and thermogravimetric analysis showed that the modifiers were immobilized on the HNT surfaces. Polycarbonate (PC)/HNT nanocomposites were prepared with the modified HNTs by a combination of solution mixing, precipitating and compression molding. The dispersion states of modified HNTs in PC nanocomposites were observed by optical microscopy, scanning electron microscopy and transmission electron microscopy. The storage modulus (E′) and thermal stability of the PC nanocomposites were enhanced by the modified HNTs. OTMS-modified HNT/PC nanocomposites showed higher performance than AEAPS-modified HNT/PC nanocomposites due to the stronger affinity of the hydrophobic alkyl groups of OTMS for the polymer matrix. This study demonstrates a low amount of halloysite nanotubes modified by a CVA process remarkably improve the thermal stability of PC nanocomposites. The n-octadecyltrimethoxysilane modifier bearing a longer alkyl tails shows stronger affinity with the matrix than the N-(2-aminoethyl)-3-aminopropyltrimethoxysilane modifier bearing shorter alkyl tails with amino group.