Device and method for optical micro-rheology for characterizing viscoelasticity of soft substance

Abstract

The invention discloses a device and a method for optical micro-rheology for characterizing the viscoelasticity of a soft substance. Coherent light generated by a laser light source is focused by a lens and irradiated on a sample to be detected in a sample cell, and a dynamic laser intensity speckle image sequence formed by scattered light after the sample to be detected is scattered is collected by a camera and transmitted to a computer for processing. And mathematical transformation is carried out on the obtained speckle light intensity diagrams of a material to be detected at different moments to obtain a pseudo-phase diagram of the speckles, and optical vortex position information can be obtained through the pseudo-phase diagram. Statistical information of mean square displacement of the optical vortex in unit time at different moments is obtained through calculation by tracking random motion of the optical vortex, and information for characterizing the viscoelasticity of the material to be detected is finally obtained through the corresponding relation between the viscoelasticity of the material to be detected and the mean square displacement of the vortex point. A measuring system is simple, only a trace sample is needed, particle movement in the sample does not need to be tracked, and high-frequency response which cannot be obtained by a traditional rheometer can be obtained.

Description

technical field [0001] The invention relates to an optical microrheology method and device for characterizing material viscoelasticity, in particular to an optical microrheology measurement device and method based on optical vortex motion statistics. Background technique [0002] Viscoelasticity is an important mechanical property of matter. A rheometer is an instrument that measures the viscoelasticity of a substance. Traditional rheometers measure viscoelasticity by measuring the stress applied to the medium and the deformation of the medium. Commonly used rheometers include rotational rheometers, capillary rheometers, torque rheometers, and interfacial rheometers. [0003] Microrheology is a method for characterizing the viscoelasticity of media by tracking the Brownian motion of particles in the media. Optical microrheology is an optical method based on dynamic light scattering (DLS) or diffusion spectroscopy (DWS). Movement, and according to the generalized Stokes-E...

AI Technical Summary

Problems solved by technology

The whole process is more complicated

[0008] The main disadvantage of optical measurement based on DLS and DWS is that the calculation is complicated, and it needs to use multiple theories such as DLS, DWS, and GSER for calculation.

The traditional mechanical rheological measurement methods have the disadvantages of complex design, expensive, time-consuming, and need to directly contact the sample to be tested.

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