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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 μm.

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.

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.

非溶媒中におけるポリメタクリル酸メチル(PMMA)薄膜の密度分布を中性子反射率測定に基づき評価した．非溶媒として水，ヘキサン，メタノールを用い，各種溶媒中における PMMA 薄膜の密度分布を評価した．その結果，水界面においては，PMMA 分子鎖がセグメントレベルで溶解することを明らかにした．また，水よりも PMMA と親和性の低いヘキサン界面においては，水を用いた際のようなセグメント溶解は起こらないこと，メタノール中では膜全体が膨潤することを明らかにした．非溶媒にアルコールを用いた場合，膜中における分子鎖は擬平衡状態にあるといえる．その状態における膜中へのアルコール収着の程度はアルコールのアルキル鎖長に依存した．また，膜内部におけるアルコールの体積分率から PMMA とアルコール間の相互作用(χ)パラメータを算出した．さらに，アルコールと接した PMMA 界面の広がりおよび基板界面における濃縮層の厚さはそれぞれ χ パラメータおよびアルコールのモル体積に依存することを見いだした．

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 χ 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.

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 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 Tg 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 °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 on the initial PS thickness evidence that the H−Si substrate buried underneath a PS film is not oxidized by annealing. We discuss a possible explanati...

Hyper-branched polystyrenes (HBPS) were synthesized. The bulk glass transition temperature (Tg) measured by differential scanning calorimetry (DSC) for two kinds of HBPS with an equivalent Mw, 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 Tg 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.

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.

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 entang...