Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER INST PHYSICS  

With the advent of high volume manufacturing capabilities by extreme ultraviolet lithography, constant improvements in light source design and cost-efficiency are required. Currently, light intensity and conversion efficiency (CE) measurments are obtained by charged couple devices, faraday cups etc, but also phoshpor imaging plates (IPs) (BaFBr: Eu). IPs are sensitive to light and high-energy species, which is ideal for studying extreme ultraviolet (EUV) light from laser produced plasmas (LPPs). In this work, we used IPs to observe a large angular distribution (10 degrees-90 degrees). We ablated a tin target by high-energy lasers (1064 nm Nd:YAG, 10(10) and 10(11) W/cm(2)) to generate the EUV light. The europium ions in the IP were trapped in a higher energy state from exposure to EUV light and high-energy species. The light intensity was angular dependent; therefore excitation of the IP depends on the angle, and so highly informative about the LPP. We obtained high-space resolution (345 mu m, 0.2 degrees) angular distribution and grazing spectrometer (5-20 nm grate) data simultaneously at different target to IP distances (103 mm and 200 mm). Two laser systems and IP types (BAS-TR and BAS-SR) were also compared. The cosine fitting values from the IP data were used to calculate the CE to be 1.6% (SD +/- 0.2) at 13.5 nm 2% bandwidth. Finally, a practical assessment of IPs and a damage issue are disclosed. (C) 2017 Author(s).

DOI： 10.1063/1.4978526

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

Size control of the poly (1,4-phenylene-5-hydroxyisophthalamide) hollow spheres was examined by tuning the polymerization condition, focusing on concentration, temperature and solvent. Higher concentration lowered the diameter owing to the higher degree of super-saturation for nucleation. Temperature drop during the polymerization just before the nucleation was so effective to make the diameter smaller. Moreover, the diameter was susceptive to the solubility of oligomers in the solvent, and higher content of liquid paraffin in the aromatic solvent lowered the solubility, resulting in the decrease in the diameter. Based on these results, the combination of the temperature drop and the solvent effect was the most desirable to prepare the smallest hollow spheres, and the diameter of hollow spheres could be controlled from 4.4 to 0.7 mu m. (C) 2017 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.polymer.2017.01.060

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER SCIENTIFIC PUBLISHERS  

Protein adsorptions onto non-annealed (NA) and thermally annealed (TA) polyetherimide films were examined by surface plasmon resonance measurements. Proteins adsorbed onto the NA films with smaller adsorption constants in comparison with the TA films. Neutron reflectivity measurements of the two films suggested that the outermost region of the NA films swelled with larger amounts of water molecules than the TA films. It is plausible that the aforementioned difference in the protein adsorption properties is derived from the difference in the interfacial aggregation structures of the two films.

DOI： 10.1166/jnn.2014.8580

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

The extent of water sorption in a thin film of a typical glassy polymer, poly(methyl methacrylate) (PMMA), was studied by neutron reflectivity. Interestingly, the as-spun film could uptake water to 16.3 vol%, much more than the reported value of a few vol% for bulk PMMA. This can be explained in terms of the heterogeneous density distribution in the film.

DOI： 10.1039/c3ra23066j

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

At the outermost surface, aggregation states of polymers generally tend to alter to their most stable ones in response to their surrounding environment. We here apply a time-resolved contact angle measurement to study the rate of the surface reorganization of poly(methyl methacrylate) (PMMA) in water. By doing these measurements at various temperatures, it is possible to determine the apparent activation energy of the surface dynamics based on the relation of the surface relaxation time and temperature. Also, the sum-frequency generation spectroscopy revealed that the surface reorganization involves the conformational changes in the main chain part as well as the side chains. Hence, the dynamics observed here may reflect the segmental motion at the outermost region of the PMMA film, in which water plays as a plasticizer.

DOI： 10.1021/ma3002559

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Language：Japanese   Publisher：SOC POLYMER SCIENCE JAPAN  

Recently, polymeric materials have been widely used in applications such as medical materials. In these applications, the surface comes into contact with a different phase. Thus, their interfaces should be studied, both their structures as well as their dynamics. The density profiles of a perdeuterated poly (methyl methacrylate) (dPMMA) film in water, hexane, methanol, ethanol, 1-propanol, and 1-butanol were examined along the direction normal to the interface by neutron reflectivity (NR). Although these liquids are typical non-solvents for dPMMA, the liquid/polymer interfaces were diffuse in comparison with the air/polymer interface probably due to the partial dissolution of polymer segments at the outermost region of the film. Interestingly, in water, an anomalous swollen layer was formed beneath the diffused interface. On the other hand, such a swollen layer was not observed for the dPMMA films in alcohols. This is simply because alcohol molecules deeply penetrated into the films. The amounts of the alcohols penetrated are related to the interaction parameter. The fractional amount of nonsolvents at the substrate interface was higher than that in the internal region of the film.

DOI： 10.1295/koron.68.608

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Thin films of a typical glassy polymer in alcohol nonsolvents were structurally characterized by specular neutron reflectivity (NR) and were found to be discernibly swollen. The extent of penetration by the nonsolvent was determined by the chain length of the alcohol. Treating this situation as one of a macroscopic phase separation, the interaction chi parameters for the polymer and nonsolvents combinations were extracted. This observation leads us to investigate the factors that control the nonsolvent/polymer interface, being an unusual example of a liquid/liquid interface. The fractional amount of nonsolvents at the substrate interface was higher than that in the internal region of the film. This segregation of a component in a phase-separated domain was explained in terms of an entropic factor.

DOI： 10.1021/jz100041h

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Qualitatively different thickness dependences have been observed in the glass transition temperature, T-g of polystyrene (PS) films supported by hydrogen-passivated silicon (H-Si). It has been suggested that upon annealing at high temperatures in air, the polymer/substrate interface of these films (i.e., PS/Si), though buried underneath the PS layer, might be oxidized, rendering the films a different polymer/ substrate interface (i.e., PS/SiOx-Si), which may account for the different thickness dependences of the T-g observed. In this experiment, we examine if the buried Substrate interface of PS/H-Si films can indeed be oxidized by annealing the films at 150 degrees C in air. Our result shows that a residual film does form on top of the H-Si surface, but it is a bound layer of PS. X-ray photoelectron spectroscopic (XPS) analyses and independence of the residual film oil the initial PS thickness evidence that the H-Si substrate buried underneath a PS film is not oxidized by annealing. We discuss a possible explanation to how the different thickness dependences may be observed in the T-g of these films.

DOI： 10.1021/ma901851w

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

A spin-coating method with the aid of selective solvents has been used to construct m,u. Itilayer struct ures for organic devices under the assumption that the solvents do not invade, a preformed structure. To confirm the assumption, we examined the interfacial width (lambda(i)) of model polymer bilayers, composed of polystyrene and perdeuterated poly(methyl methacrylate), prepared by spin-coating and notation methods. Neutron reflectivity measurements revealed that the lambda(i) value was,larger for the spin-coating method than for the flotation method. These results cast doubt on the validity of the assumption. This knowledge should be kept in mind when this method is applied to construct multilayer structures.

DOI： 10.1021/am9004336

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

Hyper-branched polystyrenes (HBPS) were synthesized. The bulk glass transition temperature (T-g) measured by differential scanning calorimetry (DSC) for two kinds of HBPS with an equivalent M-w, which were fractionated from different lots, were different, being respectively higher and lower than that of the corresponding linear polystyrene (PS). Infrared spectroscopy revealed that the T-g of HBPS increased with an increasing extent of intramolecular cross-linking, or cyclization, in the molecule. The segmental dynamics of HBPS was examined by dynamic mechanical analysis. The relaxation temperature for the segmental motion in HBPS was consistent with the DSC results. The fragility index was always lower for HBPS than for the linear PS, regardless of its primary structure and chain end chemistry. This would indicate that the segmental motion for HBPS is less cooperative than that of the linear PS, probably due to a lack of intermolecular chain entanglements in HBPS. (C) 2009 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.polymer.2009.08.029

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

Morphology for films of poly(methyl methacrylate) with various molecular weights was observed before and after methanol immersion by using atomic force microscopy so that the effect of chain entanglement on film retention of a polymer in a liquid can be discussed.

DOI： 10.1246/cl.2008.326

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Density profiles of a perdeuterated poly(methyl methacrylate) (dPMMA) film spin-coated on a substrate in water, hexane, and methanol, which are "nonsolvents" for dPMMA, were examined along the direction normal to the interface by specular neutron reflectivity (NR). The interfaces of dPMMA with the liquids were diffuse in comparison with the pristine interface with air; the interfacial width with water was thicker than that with hexane. Interestingly, in water, the dPMMA film was composed of a swollen layer and the interior region, which also contained water, in addition to the diffused layer. The interface of dPMMA with hexane was sharper than that with water. Although there were slight indications of a swollen layer for the dPMMA in hexane, the solvent molecules did not penetrate significantly into the film. On the other hand, in methanol, the whole region of the dPMMA film was strikingly swollen. To conserve mass, the swelling of the film by the nonsolvents is accompanied by an increase in the film thickness. The change in the film thickness estimated by NR was in excellent accord with the results of direct observations using atomic force microscopy (AFM). The modulus of dPMMA in the vicinity of the interfaces with liquids was also examined on the basis of force-distance curves measured by AFM. The modulus decreased closer to the outermost region of the film. The extent to which the modulus decreased in the interfacial region was consistent with the amount of liquid sorbed into the film.

DOI： 10.1021/la702132t

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Microphase-separated structures of a poly(deuterated styrene-block-2-vinylpyridine) (dPS-b-P2VP) block copolymer in thin films were studied by neutron reflectivity (NR) and transmission electron microtomography (TEMT). The dPS-b-P2VP block copolymer shows a cylindrical morphology in the bulk state. The block copolymer was spun-coated on a Si substrate, which was extensively annealed (170 degrees C for 14 days) before the NR experiments. The annealed thin film showed a featureless NR profile, the reflectivity monotonically decreased with the increasing scattering vector along the depth direction of the thin film, qz. The portion of the dPS-b-P2VP block copolymer thin film used in the NR experiment was examined by TEMT, from which a three-dimensional (3D) morphology of the block copolymer thin film was successfully obtained. The 3D image clearly showed that the microphase-separated structure inside the thin film had a cylindrical morphology with some order along the depth, but almost no in-plane order. In order to analyze the NR profile by a conventional model fitting method, a model structure that exhibits a concentration profile is necessary as an initial "guess". In this study, two different models, i.e., (i) hexagonally packed P2VP cylinders laying parallel to the Si substrate based on the known lattice parameters, and (ii) experimentally obtained TEMT 3D structure, were proposed. The concentration profiles evaluated from these two models were used as the initial guesses in the fitting of the calculated profiles to the experimentally obtained NR profile, R-exp. It was found that the fitting based on the former model failed, while the fitting based on the latter one had an excellent fit to the Rexp, This result demonstrates that the microphase-separated structures that are NOT perfectly periodic nor oriented can still be analyzed by our new technique.

DOI： 10.1021/ma071334c

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Publishing type：Research paper (scientific journal)  

Density profiles of a perdeuterated poly(methyl methacrylate) (dPMMA) film spin-coated on a substrate in water (H2O) and deuterated water (D2O) were examined along the direction normal to the interface by specular neutron reflectivity (NR). Although H2O and D2O were typical non-solvents for dPMMA, their interfaces were more diffuse than the air/dPMMA interface due to the swelling caused by the sorption of H 2O and D2O molecules. An isotopic effect on aggregation structure of the dPMMA film in water was also discussed. © 2007 IOP Publishing Ltd.

DOI： 10.1088/1742-6596/83/1/012023

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

A novel approach to surface modification of polymer films is proposed on the basis of graft polymerization initiated from photosensitizers attached to hyperbranched polymers which are localized at the film surface.

DOI： 10.1246/cl.2007.808

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATURE PUBLISHING GROUP  

Interfacial structure of deuterated poly(methyl methacrylate) (dPMMA) and polystyrene (dPS) films with gases such as carbon dioxide (CO2) and nitrogen (N-2) under a pressure of 0.1 MPa was examined by neutron reflectivity (NR). The interface was analyzed using a model that the density of the outermost region of the films was lower than that of the interior region. The density profile was expressed by a single exponential equation with a decay length (xi). The xi values for the dPMMA films under CO2 and N-2 were larger than that under vacuum at a given temperature, and the extent was more remarkable under CO2 than under N-2. On the other hand, such a gas sorption was not clearly discerned for the dPS films. Finally, the surface relaxation in the dPMMA and dPS films under CO2 and N-2 was discussed on the basis of lateral force measurements.

DOI： 10.1295/polymj.PJ2007070

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Publishing type：Research paper (international conference proceedings)  

Aggregation structure of (hyperbranched polystyrene/linear polystyrene) blend films was examined by dynamic secondary ion mass spectroscopy (DSMS) and neutron refflectivity (NR). Two types of monodisperse hyperbranched polystyrenes (HB-PS) with longer and shorter branches were synthesized combing cationic and anionic polymerizations. Total molecular mass for the both was fixed to be 1M. Deuterated polystyrene (dPS) with molecular weight of 1M was used as a linear component. DSMS and NR measurements revealed that HB-PS are preferentially segregated at both surface and substrate interface. Interestingly, to what extent HB-PS exists at the surface and interface was dependent on the architecture of HB-PS. This might be explained in terms of number density of chain ends and distorted chain conformation. The above results were in good accordance with a prediction based on simulation using a self-consistent filed theory. Finally, a possibility of HB-PS as a surface or interfacial modifier is discussed.

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