I would like to show you AFM topos of polysilane single chains.
All topos were observed in air.
(Sorry, still under constructions!)
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Si(111) surface AFM topography of Si(111) surface treated by NH4F. The right triangle patterns are seen over the surface, which are of Si(111) surface structure with a step height of 0.34 nm. |
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nano NTT BRL marking It is not easy, or even very hard, to obaserve always the same place by using AFM. These are the marks for identifying the place where we are observing (30 X 7.5 micron image). The depth of the mark is 10-20 nm, appropriate for the observations of small structures on the surface. However, it is also observable by optical microscpe, which makes us readily go back to the same observation areas. |
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Single Polymer Chain Have you ever seen the single polymer chains? If your answer is "no", here you can see them. Material: Poly[(S-2-methylbutyl)decyl]silane Seeing is believing. |
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End-Grafted Polysilane If you are lucky, you can get such a nice image like one above. However, it is not easy to have a sample with isolated polymer chains on its surface. Our end-grafted polysilane sample gives us a unique oppotunity to observe single polymer chains anywhere on its surface. |
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Single Molecular Structure of Flexible Polysilane We want to see the stretched chain-like image for single polymer chain. But the results are often different from our wish upon a star... The dots observed here are the structures of single poly(methylphenylsilane). The polysilane has a repulsive interaction with the air, and form a structure with a minimum surface area contacting to the air. The structures are common ones for end-grafted flexible polymers. (remember that most of polymers we know are in this category) |
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Single Molecular Structure of Semi-flexible Polysilane As is expected, we can observe the wire-like structure if we use rigid rodlike polysilane. We can observe small ring structures, which was not observed for the AFM of the same polymer but not grafted. The structure unique for the end-grafted semiflexible polymer was theoretically predicted recently, and was named "toroid". (2000 X 2000 nm) |
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Make a Knot This is a magnification of the toroid structure. Two polymer chains coming to the each side of the observation area meet and shake hands each other. (300 X 300 nm) |
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Octopus Octopus structures made of end-grafted poly(di-n-hexylsilane). The structures agree with the theoretically predicted structure of common flexible polymers end-grafted on solid surface. |
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Octopus with Four Tentacles Four chains are agglomerated in the center of their grafting point. Although this type of structure was theoretically predicted recently, I think this is a nice and unique experimental result to clearly confirm it. (300 X 300 nm) |
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