Most polymers solidify into a glassy amorphous state, accompanied by rapid increase in the viscosity when cooled below glass transition temperature (T(g)). There is an ongoing debate on whether T(g) changes with decreasing polymer film thickness and origin of changes. We measured unentangled, short-chain polystyrene films silicon at different temperatures found that for decreases thickness, consistent observed before. By applying hydrodynamic equations to films, data can be explained...

Qualitatively different thickness dependences have been observed in the glass transition temperature, Tg, of polystyrene (PS) films supported by hydrogen-passivated silicon (H−Si). It has suggested that upon annealing at high temperatures air, polymer/substrate interface these (i.e., PS/Si), though buried underneath PS layer, might be oxidized, rendering a PS/SiOx−Si), which may account for Tg observed. In this experiment, we examine if substrate PS/H−Si can indeed oxidized 150 °C air. Our...

The local conformation of polymer chains in a film at substrate interface was examined by sum-frequency generation spectroscopy. When polystyrene (PS) prepared on quartz spin-coating method, the were aligned interfacial plane substrate. A dissipative particle dynamics simulation revealed that spinning torque induced chain orientation during preparation process and extent function distance from interface. This not observed for PS solvent-casting method. Interestingly, unchanged even...

There are increasing requirements worldwide for advanced separation materials with applications in environmental protection processes. Various mesoporous polymeric have been developed and they considered as potential candidates. It is still challenging, however, to develop economically viable durable from low-cost, mass-produced materials. Here we report the fabrication of a nanofibrous network structure common polymers, based on microphase technique frozen polymer solutions. The resulting...

At the outermost surface, aggregation states of polymers generally tend to alter their most stable ones in response surrounding environment. We here apply a time-resolved contact angle measurement study rate surface reorganization poly(methyl methacrylate) (PMMA) water. By doing these measurements at various temperatures, it is possible determine apparent activation energy dynamics based on relation relaxation time and temperature. Also, sum-frequency generation spectroscopy revealed that...

Epoxy structural adhesives have been used extensively in the automotive and aerospace industries to bond assembly parts. Much effort has devoted enhancing mechanical properties of epoxy resin by incorporating fillers. Among a variety fillers investigated for this purpose, nanocelluloses are regarded as promising type emerging green filler material because their excellent physicochemical properties. Indeed, polymer nanocomposites. However, toughening reinforcing effects on rigid not yet fully...

Density profiles of a perdeuterated poly(methyl methacrylate) (dPMMA) film spin-coated on substrate in water, hexane, and methanol, which are "nonsolvents" for dPMMA, were examined along the direction normal to interface by specular neutron reflectivity (NR). The interfaces dPMMA with liquids diffuse comparison pristine air; interfacial width water was thicker than that hexane. Interestingly, composed swollen layer interior region, also contained addition diffused layer. hexane sharper...

The glass transition temperature (Tg) of thin polystyrene (PS) films supported on silicon wafers with oxide layers varying thickness was characterized by the dependence film using ellipsometry. This allowed us to uncover how a long-range interaction affects Tg polymer films. As previously reported variety methods, decreased decreasing thickness. However, extent not same among reports. In this study, we found that attenuation PS given dependent layer wafer via interaction.

Hydrophobized plant polyphenols can be easily prepared by rational and controlled etherification of highly abundant aromatic hydroxyls with linear alkyl chains. The resultant organo-soluble spontaneously formed fibrous structures unravelled to potential adhesive, anticorrosion, antibacterial coatings.

Reversible dynamic control of structure is a significant challenge in molecular nanotechnology. Previously, we have reported mechanically induced continuous (analog) conformational variation an amphiphilic binaphthyl, where closing pliers was achieved by compression monolayer composed these molecules at the air-water interface. In this work report that phase transition applied mechanical stress enables discontinuous digital (1/0) opening simple binaphthyl pliers. A lipid matrix interface...

Associative phase separation (complex coacervation) in liquid–liquid (LLPS) involves the of multiple substances into concentrated and dilute phases by electrostatic interactions. Simple (simple occurs when hydrophilicity hydrophobicity a single molecule change dramatically response to specific stimulus. coacervation arises from lower critical solution temperature (LCST)- upper (UCST)-type separations aqueous media containing temperature-responsive polymers. LCST- UCST-type LLPSs induce...

Bioinspired organic polymer is demonstrated for efficient and versatile corrosion resistance. Present method affords a thin, transparent highly adhesive protective coatings wide range of structural metals/alloys.

In some synthetic polymers used for medical applications, hydration water in the vicinity of polymer chains is known to play an important role biocompatibility and referred as intermediate water. The crystallization below 0 °C observed during thermal analysis has been considered evidence presence However, origin physicochemical properties have not yet elucidated. this study, a typical biocompatible polymer, poly(ethylene oxide) its were investigated with use terahertz time-domain...

We have measured the effective viscosity of polystyrene films with a small (4 wt %) added amount dioctyl phthalate (DOP) deposited on silica. A broad range molecular weights, Mw, from 13.7 to 2100 kg/mol was investigated. Our result shows that for thin Mw < ∼100 addition DOP causes decrease by factor ∼4, independent Mw. But higher films, creeps toward neat increasing model assuming be dominated enhanced surface mobility lower but surface-promoted interfacial slippage is able account...

Hydrophobic mesoporous polymer nanofibre networks were converted to hydrophilic ones by a mild sulfonation reaction. The resultant polystyrene with large free surface area effectively captured water-soluble dye molecules and allowed aromatic compounds rapidly permeate into the internal binding sites.

The relaxation behavior of poly(methyl methacrylate) (PMMA), spin-coated on a silicon wafer, at the water interface was examined by lateral force microscopy as function temperature and scanning rate. Even in water, peak which assigned to segmental motion PMMA plasticized molecules clearly observed domain. apparent activation energy for αa-relaxation process much smaller than those original processes intact surface bulk. depth profile glass transition (Tg) film obtained, showing that Tg...

A biomimetic design has been explored to achieve high-performance polymer glue with tuneable strength and ductility, which is suitable for a wide-range of substrates under both similar dissimilar bonding.

Polysiloxanes exhibit practical properties not observed in carbon or carbon–oxygen backbone polymers. Linear ionic polysiloxanes containing an amine hydrochloric salt a humidity-induced self-assembly (HiSA) behavior. HiSA leads to nanoscale structuring by the uptake of absorbed water around aggregates polymer, promoting hydrophilic–hydrophobic phase separation polymer. The resulting polymer forms self-assembled lamellar nanostructure with period ca. 1.6 nm. Herein, we investigate factors...

A novel perfluoropolyether (PFPE) structure terminated on one chain end by a hydroxyl group and the other cyclotriphosphazene derivative was studied. The interactions that developed at interface between molecularly thin films of this material (A20H) amorphous nitrogenated carbon surfaces were investigated using contact angle goniometry, Fourier transform infrared spectroscopy, X-ray photoelectron imaging ellipsometry. results demonstrate both monolayer A20H are capable attractive with...

Abstract Neutron reflectivity revealed that the surface aggregation states of poly(methyl methacrylate) film can be altered by water, which is a typical nonsolvent, in relatively large scale.