Method for acquiring diffusive and directional movement information of single polymer molecules in shear fields

Abstract

The invention discloses a method for obtaining the diffusion and directional motion information of a single polymer molecule under a shear field. The method comprises the following steps: (1) preparing a polymer solution with a concentration below 10nM, and marking the fluorescent molecular probe on the polymer molecule; (2) irradiating the marked polymer solution with laser light while applying a shear field , to collect the emitted fluorescent signal, the diffusion and directional motion information of a single polymer molecule can be obtained; the measurement system used includes an excitation light source unit, a shear application and rheological measurement unit, an optical microscope unit and a fluorescence An associated spectral measurement unit, wherein the shear application and the bottom of the rheological measurement unit are provided with an excitation light optical window. The method of the invention can not only implement precise dynamic shearing to measure the macroscopic rheological properties of the polymer solution, but also can study the microscopic physical image of the polymer solution from the perspective of single molecules.

Description

technical field [0001] The invention relates to a method for obtaining the diffusion and directional movement information of a single polymer molecule under a shear field, and belongs to the field of fundamental research of polymer physics. Background technique [0002] Measuring the diffusion information of polymer molecules in their good solvents has always been an important basic research work in the field of polymer physics. The diffusion of polymer molecules in its good solvent is closely related to its molecular conformation. Research in this area will not only help us better understand the microscopic physical processes of the macroscopic properties of polymer solutions, but also help us understand the microscopic aspects of some life processes. physical nature. [0003] Diffusion can be roughly divided into bulk diffusion and interfacial diffusion or two-dimensional confined diffusion. For bulk diffusion, Han Zhichao, Institute of Chemistry, Chinese Academy of Scie...

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Problems solved by technology

[0004] However, the total internal reflection single-molecule fluorescence imaging technology can obtain the diffusion information from the perspective of a single molecule for slow diffusion systems (gels, films, etc.), but it loses information for fast diffusion systems (polymer dilute solutions, etc.). Vitality; light scattering technology can obtain the diffusion information of neutral polymer molecules very well, but due to the limitation of polymer concentration and scattering cross section, it is not suitable for the measurement of the diffusion of multi-charge systems, so it cannot meet the requirements of multi-charge system research. need

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