| Project/Area Number |
12650886
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
高分子構造・物性(含繊維)
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| Research Institution | Kyushu University |
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Principal Investigator |
KIKUCHI Hirotsugu Faculty of Engineering, Associate Professor, 大学院・工学研究院, 助教授 (50186201)
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| Co-Investigator(Kenkyū-buntansha) |
SASAKI Sono Faculty of Engineering, Assistant Professor, 大学院・工学研究院, 助手 (40304745)
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| Project Period (FY) |
2000 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥4,000,000 (Direct Cost: ¥4,000,000)
Fiscal Year 2002: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2001: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2000: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Keywords | single chain / entropic elasticity / Langevan function / freely-jointed chain |
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| Research Abstract |
It is well known that a restoring force by entropic elasticity is acted on the ends of a polymer chain upon stretching a flexible poly* chain in a random coil state. The atomic force microscope (AFM) has enabled direct stretching measurement for single polymer chains * which both the ends of a polymer chain could be adsorbed at an AFM probe tip and substrate surfaces. In this study, an entro* elasticity of a stretched single polystyrene chain was directly measured with AFM in a dilute solution of mono-disperse polystyrene(* and the relationship between applied force and end-to-end distance of PS chain with different molecular weights was investigated.
Each end of mono-disperse PS was modified with a carboxyl group which can form a linkage to an amino group on the surfaces * probe tip and a substrate. The shape of the force-distance curve could be explained by the model of freely jointed segments which * elastically deformable during stretching. The magnitude of the maximum stretching fo
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rce ranged 200-500 pN, which could correspo* to the breaking force of hydrogen bonding formed between a PS chain end and the probe tip or the substrate surface. The maxim* extension was found to be longer with increasing molecular weight. The average of the experimental maximum extensions was ab* 60〜70 % as long as of the molecular contour length. From analogy of simulations with the freely jointed chain model, the observ* curves could result from entropic elasticity of an elongated random coil. The extension of a PS chain in a methanol solution * smaller than that in a toluene one, though the Mn of a PS chain in each solution was same. Generally, the dimension of a random * of a polymer chain in a poor solvent is smaller than that in a good solvent. Since methanol is much poorer solvent to PS compared * toluene, a radius of gyration of a PS chain in a methanol solution should be much smaller than that in a toluene solution. Therefore* larger force was required to stretch a PS chain in a methanol solution in comparison with that in a toluene solution. Less
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