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We used fluorescencemicroscopy to show that low adsorption ofresin components by a mold surface was necessary for continuous ultraviolet(UV) nanoimprinting, as well as generation of a low release energyon detachment of a cured resin from a template mold. This is becausewith low mold pollution, fracture on demolding occurred at the interfacebetween the mold and cured resin surfaces rather than at the outermostpart of the cured resin. To achieve low mold pollution, we investigatedthe radical photopolymerization behaviors of fluorescent UV-curableresins and the mechanical properties (fracture toughness, surfacehardness, and release energy) of the cured resin films for six typesof di(meth)acrylate-based monomers with similar chemical structures,in which polar hydroxy and aromatic bulky bisphenol moieties and methacryloylor acryloyl reactive groups were present or absent. As a result, weselected bisphenol A glycerolate dimethacrylate (BPAGDM), which containshydroxy, bisphenol, and methacryloyl moieties, which give good mechanicalproperties, monomer bulkiness, and mild reactivity, respectively,as a suitable base monomer for UV nanoimprinting under an easily condensablealternative chlorofluorocarbon (HFC-245fa) atmosphere. The fluorescentUV-curable BPAGDM resin was used for UV nanoimprinting and lithographicreactive ion etching of a silicon surface with 32 nm line-and-spacepatterns without a hard metal layer. [ABSTRACT FROM AUTHOR]

The magnitude and sign of the volume change upon protein unfoldingare strongly dependent on temperature. This temperature dependencereflects differences in the thermal expansivity of the folded andunfolded states. The factors that determine protein molar expansivitiesand the large differences in thermal expansivity for proteins of similarmolar volume are not well understood. Model compound studies havesuggested that a major contribution is made by differences in themolar volume of water molecules as they transfer from the proteinsurface to the bulk upon heating. The expansion of internal solvent-excludedvoids upon heating is another possible contributing factor. Here,the contribution from hydration density to the molar thermal expansivityof a protein was examined by comparing bovine pancreatic trypsin inhibitorand variants with alanine substitutions at or near the protein–waterinterface. Variants of two of these proteins with an additional mutationthat unfolded them under native conditions were also examined. A modestdecrease in thermal expansivity was observed in both the folded andunfolded states for the alanine variants compared with the parentprotein, revealing that large changes can be made to the externalpolarity of a protein without causing large ensuing changes in thermalexpansivity. This modest effect is not surprising, given the smallmolar volume of the alanine residue. Contributions of the expansionof the internal void volume were probed by measuring the thermal expansionfor cavity-containing variants of a highly stable form of staphylococcalnuclease. Significantly larger (2–3-fold) molar expansivitieswere found for these cavity-containing proteins relative to the referenceprotein. Taken together, these results suggest that a key determinantof the thermal expansivities of folded proteins lies in the expansionof internal solvent-excluded voids. [ABSTRACT FROM AUTHOR]

Direct observation of the molecular orientation change in polymer crystals provides us visible information for understanding their structural phase-transition mechanisms. In this letter, we successfully identified the main-chain orientation of poly(vinylidenefluoride-trifluoroethylene) (P(VDF-TrFE)) crystals over all directions using friction anisotropy measured by lateral-modulation friction force microscopy (LM-FFM). This technique made possible our investigation of molecular orientation changes caused by a ferroelectric phase transition and also a fabrication process for artificial nanometer-scale structures. These results give us visual information that is directly connected to the transition mechanisms. [ABSTRACT FROM AUTHOR]

Poly(vinylidene fluoride) film formation with electrospray deposition has been studied with support of a droplet evaporation model. The input parameters of the model consist basically of the solvent, the solute concentration, the flow rate, and the solution conductivity. The model provides the droplet size, the solute concentration, the droplet velocity, and the shear stress of the droplet at impact as a function of the distance between the nozzle and the substrate. With some additional experimental information such as the size change of the film with spray distance and the viscosity of the solution, the growth rate of the film and the shear rate of the droplet at impact can be determined. Growth rate is shown to define distinct regimes of film formation. In those regimes, only a single factor or a limited number of factors controls the film morphology. The most important factors include the shear rate and the surface energy. It is found that at a specific range of growth rates only the shear rate determines the morphology of the polymer film. Growth rate, as the defining quantity of film morphology, is not limited to polymer solutions. Therefore, the growth rate, in combination with the control factors mentioned above, functions as a general framework through which understanding and control of film formation with electrospray deposition can be improved. [ABSTRACT FROM AUTHOR]