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Poly(etheretherketone) (PEEK) substrate surface was modified with charged cationic poly(2-(methacryloyloxy) ethyltrimethylammonium chloride) (PMTAC) and anionic poly(3-sulfopropyl methacrylate potassium salt) (PSPMK) polymer brushes through surface-initiated radical polymerization triggered by UV light exposure of benzophenone groups in PEEK backbone as an initiator. After extensive UV light exposure, the PEEK surface was covered with grafted polyelectrolyte chains and exhibited swollen polyelectrolyte brushes with high roughness under water, indicating high graft density and wide molecular weight distributions of PMTAC and PSPMK brushes. The hydrated polyelectrolyte brushes on PEEK surface induce significant air bubble repellency in water. Thus, thickening of swollen polyelectrolyte brushes dramatically reduces the friction coefficient of PEEK surface under a wet condition. [ABSTRACT FROM AUTHOR]

Polyurethane elastomers (PUEs) based on poly(2-ethyl-1,3-hexamethylene adipate) glycol (PEHA), poly(2,4-diethyl-1,5-pentamethylene adipate) glycol (PDEPA) and poly(2-butyl-2-ethyl-1,3-trimethylene adipate) glycol (PBETA) were synthesized with 4,4’-diphenylmethane diisocyanate (MDI) and 1,4-butane diol (BD)/1,1,1-trimethylol propane (TMP). PEHA has one primary and one secondary hydroxyl groups, but PDEPA or PBETA has two primary hydroxyl groups. The effect of low reactive secondary OH group on molecular aggregation structure and mechanical properties of the PUEs was investigated using Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), small-angle X-ray scattering (SAXS), dynamic viscoelastic measurement and tensile testing. The study demonstrates that PEHA-based PUE has lower cross-linking density and lower degree of microphase separation than PDEPA- and PBETA-based PUEs. As a result, PEHA-based PUE has lower dynamic storage modulus value at the rubbery plateau region and Young's modulus. [ABSTRACT FROM AUTHOR]

Poly(alkylaniline) grains with several tens micrometer-sized diameter were successfully synthesized by aqueous chemical oxidative polymerization. The grains were aggregates consisting of submicrometer sized-atypical particles, which was confirmed by scanning electron microscopy studies. Static contact angle measurements of water droplets on the compressed pellets of the grains indicated that the hydrophobicity increased with an increase of alkyl group length and the alkyl groups bonded to phenyl ring is expected to be exposed to air phase. The data obtained through thermography indicated the grains showed near infrared light-to-heat photothermal property. The dried grains could work as an effective liquid marble stabilizer by efficient adsorption to air-water interface. The remote locomotion control of liquid marble could be attained by near-infrared light-induced Marangoni flow. Furthermore, the liquid marbles could detect oil contamination on water surface by disruption. Synthesis of poly(alkylaniline) grains as a stimuli-responsive liquid marble stabilizer by aqueous chemical oxidative polymerization. Image 1 • Poly(alkylaniline) grains were synthesized by aqueous chemical oxidative polymerization. • Poly(alkylaniline) grains functioned as a liquid marble stabilizer. • Light irradiation induced locomotion of liquid marble due to Marangoni propulsion. • Liquid marble could detect oil contamination on water surface. [ABSTRACT FROM AUTHOR]

The effect of molecular mobility of a pre-crystallized phase on the isothermal crystallization in the microphase-separated lamellar morphology of a strongly segregated crystalline-crystalline block copolymer, poly(ethylene glycol)- block -poly(perfluorooctylethyl acrylate) (PEG- b -PFA-C 8 ), was investigated. The diblock copolymer produced a microphase-separated lamellar morphology in the melt state, and the precedent crystallization of PFA-C 8 blocks provided the lamellar confinement field. The counter PEG block crystallized within the lamellar confinement field. The molecular mobility of the pre-crystallized PFA-C 8 phase was modulated by the thermal history. The structural evolution was monitored by a complementary combination of in situ time-resolved simultaneous small-angle X-ray scattering/wide-angle X-ray diffraction measurements and thermal analyses. The degree of crystallinity and the melting temperature of the PEG crystals were associated with the molecular mobility of the pre-crystallized PFA-C 8 phase. The highly packed PFA-C 8 phase (higher-ordered phase) constrained the PEG crystallization, whereas the loosely packed PFA-C 8 phase (lower-ordered phase) caused a weak restriction in the PEG crystallization to give relatively ordered PEG crystals. Subsequent crystallization in a confinement field of crystalline-crystalline block copolymers was controlled by adjusting the molecular mobility of the pre-crystallized phase. [ABSTRACT FROM AUTHOR]

The surface dynamics of polyhedral oligomeric silsesquioxane (POSS)-functionalized polystyrene (PS-POSS) thin films above the glass transition temperature were studied by grazing-incidence X-ray photon correlation spectroscopy in order to elucidate the effects of POSS at the end of the polystyrene chains. Much slower fluctuations were observed in the surface of PS-POSS thin films than in the polystyrene thin films, despite the negligible difference in their bulk viscosity. Quantitative analysis based on fluctuation-dissipation theorem indicated that there is a high-viscosity layer at the surface of the PS-POSS films, and that the substrate interface originated from POSS segregation. [ABSTRACT FROM AUTHOR]

Crystallization-induced structure fluctuations in the layer thickness direction and disordering of pre-crystallized structure in crystallized microdomain structure that consist of a strongly segregated crystalline-crystalline diblock copolymer, poly(ethylene glycol)- block -poly(perfluorooctyl ethyl acrylate) (PEG- b -PFA-C 8 ), were investigated. The structure formation process during isothermal crystallization was monitored by in-situ time-resolved simultaneous SAXS/WAXD measurements and thermal analysis. At early stage of isothermal crystallization, three dimensional growth of the PEG lamellar crystals within lamellar microphase-separated morphology induced the volume shrinkage of PEG phase, resulting in the reduction of PEG layer thickness, increase of PFA-C 8 layer thickness and disordering of pre-crystallized PFA-C 8 crystals. At late stage of isothermal crystallization, one dimensional growth, thickening of PEG lamellar crystals induced the increase of PEG layer thickness and reduction of PFA-C 8 layer thickness. The structure fluctuation in the crystallized microdomain structure depends on the crystal growth dimension. [ABSTRACT FROM AUTHOR]

An effect of surface segregation of polyhedral oligomeric silsesquioxanes (POSS) on surface physical properties was investigated. Hard coating layer with various MA 8 POSS loadings was prepared on a bilayer of soft layer and PMMA substrate via a UV curing process. The scratch resistance of the coating layer showed specific properties. When MA 8 POSS loadings in the coating layers were less than 10 wt %, the coating layers showed a great performance in scratch resistance. While MA 8 POSS loadings were higher than 10 wt %, the surface performance was deteriorated. This is because the outermost surface of the coating layer was covered by MA 8 POSS molecules when the MA 8 POSS loadings were higher than 10 wt %, resulting in uncompleted curing reaction caused by large steric hindrance of MA 8 POSS. [ABSTRACT FROM AUTHOR]

• Particle-stabilized bubble was coated by polyaniline overlayer. • Bubble coated by polyaniline overlayer showed photothermal property. • Laser irradiation induced locomotion of bubble due to Marangoni propulsion. • Bubble could work as an adhesive under water. Polystyrene particle-stabilized bubbles were successfully coated with polyaniline overlayers by aqueous chemical oxidative polymerization, and the loading amount of polyaniline to the bubbles could be controlled simply by changing aniline concentration in the polymerization media. Remote motion control of the particle-stabilized bubbles coated by the polyaniline overlayers was realized on a planar air–water surface by light irradiation, due to light-to-heat photothermal property of the polyaniline. A Marangoni flow induced by site-selective light irradiation of the bubble could work as a driving force to move the bubble on the water surface, and the direction and timing of irradiation could control the direction and timing of the motion on demand. Pathlength, velocity, acceleration and force of the bubble motions became longer and larger with an increase of polyaniline loading amount on the bubbles, which was confirmed by numerical analyses. Furthermore, the bubbles were demonstrated to be able to adhere two solid substrates under water after disruption by application of compressive stress. [ABSTRACT FROM AUTHOR]