Environment dependence of single polymer chain stretching and application to molecular spring

单链聚合物链拉伸的环境依赖性及其在分子弹簧中的应用

基本信息

批准号：
12650886
负责人：
KIKUCHI Hirotsugu
金额：
$ 2.56万
依托单位：
Kyushu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12650886/
关键词：
single chain entropic elasticity Langevan function freely-jointed chain

项目摘要

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 … More 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

众所周知，在拉伸柔性 *状态后，原子力显微镜（AFM）在聚合物链上作用于聚合物链。可以在AFM探针尖端和底物表面。研究了具有不同分子量的链。Eno-Dis Perse PS用羧基修饰，可以在表面上形成与氨基的ANKAGE *探针尖端和底物。在拉伸期间的自由接头段。 ER的分子量增加。甲醇溶液中的链条 *较小的，在甲苯溶液中，ACH溶液战争中PS链的Mn，杆溶剂的随机 *的尺寸是良好的溶剂。溶剂与PS *甲苯（在PS链中的PS链中的PS链）中的溶剂与甲醇溶液中PS链拉伸所需的PS链相比