The brilliant blue luster of Morpho butterflies is produced by their scale that does not contain a blue pigment. The origin of the coloration can be attributed to an optical effect on a specific nano-structure, which can explain both of the high reflectivity and the mystery that the blue appears from wide angle despite an interference effect. We have successfully reproduced the Morpho-blue by fabricating nano-structure by extracting the principles of the coloration. The reproduced Morpho-type materials are expected to serve to various industrial applications. However, the process to fabricate the nano-structure spends too much time and cost using conventional lithography. To solve this problem, nano-imprint lithography was applied to fabricate the nano-structure. As a result, Morpho-color was replicated successfully in low cost and short time. Its optical properties were estimated by optical measurements, and found to show the basic characteristics of the original Morpho-blue.
Using the ability of the noncontact atomic force microscopy (NC-AFM) to image and perturb the Si(001) dimer configuration, we investigate the influence of surface stress around an SA step of Si(001) on the buckled dimer at 5 K. The NC-AFM first detected the different buckled dimer phases between the terraces: asymmetric c(4×2) phase in the upper terrace and symmetric p(2×1) one in the lower terrace appeared in both topographic and dissipation images. In addition, we found, for the first time, the dimers by the step in the upper terrace compress by 0.036±0.013 along dimer bond direction from the averaged profile analysis of the images. Variation in the surface dimer structure reflected by the surface stress was demonstrated from the dissipation image analysis, which points to the possible exploration of the surface stress by means of NC-AFM.
We developed a conductance measurement system of a single carbon fullerene simultaneously with a transmission electron microscope (TEM) observation. A single carbon fullerene was made from an agglomerate of carbon atoms suspended between both gold electrodes. When the bias voltage above 0.6 V was applied between both electrodes, the transformation into a single carbon fullerene was observed. We measured electrical conductance of the single carbon fullerene adsorbed on the electrode surface in the process of bringing the opposite side electrode close to it. The conductance showed tunneling behavior from 10−5 to 10−2 G0 (= 2e2/h ; quantized unit of conductance) and abruptly jumped to 0.5 G0. TEM observation showed that an ellipsoidal carbon fullerene expanded along the normal direction to the electrode surface and had a contact with the electrode, which corresponded to the conductance jump. The conductance value of the fullerene was 0.5-0.6 G0.
The mechanism that cells use to recognize micro-patterned topographies was clarified. First, 3D double-layer poly (ε-caprolactone) scaffolds equipped with honeycomb-patterned micro-pores (“honeycomb films”) were prepared. Then, porcine aortic endothelial cells (PAECs) were cultured on these scaffolds for 1-6 h in serum-free medium. Finally, their initial spreading process was investigated by using AFM and confocal laser scanning microscopy. The attachment and spreading of PAECs on honeycomb films having either 6-or 16-μm pore diameters resulted in voids within the cell cytoplasm, which correspond with the size and location of the honeycomb micropores. The number of cells with this unique morphology decreased with increasing culture time. This dependence of morphology on film pore size and culture time suggests a spreading process of PAECs in which the cells spread trying to sense suitable sites to adhere. Using thick filopodia, the cells spread along the rim of the film and produced pores by close contact between two spreading filopodia. Evidently, these pores became filled in during culture, presumably as the cells began to reorganize their cytoplasma.
Using collision with energy-controlled rare gas atoms, the control and analysis of the diffusion of molecules on the surface was performed in an ultra high vacuum chamber with Fourier-transform infrared (FTIR) spectrometer and a supersonic molecular beam apparatus. A stepped Pt(997) surface was exposed to CO molecules and subsequently to energy-controlled Ne or Ar atoms. There was no change in the CO stretching mode region of the FTIR spectrum of the Pt(997) surface after Ne atoms having an average translational energy of 0.23 eV were collided with it. However, when Ne atoms having an average translational energy of 0.56 eV were collided with the surface, the intensity of the peak assigned to the CO stretching mode at terrace sites decreased, while that at step sites increased with increasing the exposure to the Ne atoms. This indicates that CO molecules adsorbed at the terrace sites migrate laterally to the step sites upon collision with high-energy Ne atoms. In addition, it was shown that the direction of diffusion can be controlled, the diffusion of the molecule in particular chemisorbed state can be activated, and the activation energy of diffusion can be estimated. A new method to examine the diffusion of adsorbates by the use of the collision with energy-controlled atoms is proposed.
We have developed a confocal micro X-ray fluorescence instrument. Two independent X-ray tubes of Mo and Cr targets were installed to this instrument. Two polycapillary full X-ray lenses were attached to two X-ray tubes, and a polycapillary half X-ray lens was also attached to the X-ray detector (silicon drift detector, SDD). Finally, three focus spots of three lenses were adjusted at a common position. By using this confocal micro X-ray fluorescence instrument, depth profiling for layered samples were performed. It was found that depth resolution depended on energy of X-ray fluorescence that was measured. In addition, X-ray elemental maps were determined at different depths for an agar sample including metal fragments of Cu, Ti and Au. The elemental maps showed actual distributions of metal fragments in the agar, indicating that the confocal micro X-ray fluorescence is a feasible technique for non-destructive depth analysis and 3D X-ray fluorescence analysis.
Scanning Tunneling Microscope (STM) combined with Synchrotron Radiation (SR) allowed to analyze solid surfaces in real space with nanometer scale by inner-shell excitation of a specific energy level under the STM observation. Elemental analysis was successfully accomplished for Ge nano-islands on a Si(111) 7×7 surface by SR-STM. As a next step, remaining diffculties of instability and inaccuracy during measurements were improved. After renewal of a dumper system, a key to solve the diffculties was reduction of emitted electrons. Thus, an insulator-coated tip to shut out the electrons coming from a wide area was developed. Further surface analysis was performed for Cu domain on a Ge(111) 2×8 surface using the new tip. As a result, elemental analysis between Cu domains and the surrounding Ge surface was achieved. It has been shown that SR-STM provides new possibilities of nanoscale surface analysis.
Plasma-surface treatment is a technique to treat surfaces of various materials for a wide variety of applications. However, it has been often said that the altered nature of the plasma-treated surface does not last long. The reasons for the decay of plasma treated surfaces are considered to be (1) rotation and migration of surface moieties containing functional groups into inside of the material and (2) disappearance of relatively low-molecular-weight substances including weak boundary layer (WBL) formed in the plasma treatment. However, the decay behavior depends on materials nature, plasma condition, storage condition, and so on, and the precise mechanism is still unknown. The decay also occurs on inorganic material surfaces, and some post-reactions take place even on the plasma-polymerized film surfaces. Since plasma-treated surfaces are very thin and possess a number of active sites, a promising method to prevent the decay, at the present stage, may be immobilization of proper polymers on the surface, such as plasma-induced graft polymerization.
Recently, three-dimensional (3D) direct observations and analysis of polymer morphologies draw considerable attention because they not only provide intuitive understanding of the morphologies but also offer novel structural parameters that can never be obtained by other technique. The most sophisticated transmission electron microtomography (TEMT) achieves spatial resolution of less than 1 nm in the 3D reconstructed images. In the present paper, applications of TMET to polymer nanostructures, that is microphase-separated structures of block copolymers (Gyroid-structures), were reported in order to demonstrate huge and promising capabilities of the new technique.