Study On Deformation Response Characteristics Of Polymer Holographic Sensor

Sensors play an important role in production and life.Holographic sensor is a novel sensor,which has attracted much attention in recent years.Based on the principle of shifting diffraction peak wavelength,the holographic sensor can sense the change of the external environment through the peak wavelength of the holographic grating recorded in the photopolymer.It has the advantages of large dynamic range,narrow diffraction spectrum,low cost,flexible sensing strategy and so on.The bright color indication also has visibility.Acrylamide photoinduced polymer is a kind of ideal holographic sensing material with simple preparation process,flexible composition and high diffraction efficiency.As a kind of motion form,bending deformation is of great significance to characterize it.However,the lack of quantitative data for the characterization of bending deformation of acrylamide photoinduced polymer films limits the practical application of holographic sensors.In this paper,a holographic sensor based on acrylamide-erythrosine polymer has been developed for real-time,high precision,qualitative and quantitative characterization of the bending deformation of thin films.In this paper,an acrylamideErythrocyte red-induced polymer with excellent properties was prepared on a flexible substrate by solution blending and drip method.Then,a transmission holographic grating was recorded in the polymer with a 532 nm laser in the visible light region.The diffraction spectrum is read by supercontinuum light source.Dynamic bending is unilateral bending,static bending is bilateral bending and bilateral straightening of bending record is implemented.The obvious peak wavelength shift(up to 200 nm)provides a basis for the bending deformation of the sensing material.In the case of unilateral bending,the diffraction peak wavelength has a linear relationship with the angular displacement,the maximum measurable bending Angle is about 22 deg and the angular resolution is about 0.05 deg/0.5 nm.In the case of bilateral bending,the scanning peak wavelength sensitivity and the scanning range are also linearly related to the radius of curvature,and the radius of curvature can be sensed from 44 mm to 69 mm.When the curved grating is straightened on both sides,the wavepacket width of the rainbow spectrum has a linear relationship with the curvature radius,and the spatial width of the rainbow also has a clear negative correlation with the curvature radius.The sensing curvature radius range is extended to 20?69 mm.The bending deformation can also be qualitatively analyzed by observing the color and width characteristics of the rainbow with the naked eye.The three bending types can cover most scenes.The bending sensing data of polymer film provides an effective method to characterize the bending motion of polymer.The optical measurement of bending deformation further verifies the practicability of the holographic sensor.By means of spraying and pasting,the photoinduced polymer film is attached to the object to be tested,and the bending deformation of the object can be sensed by diffraction spectrum.The obtained results can be used for motion monitoring and mechanical analysis of soft robot,intelligent health equipment and infrastructure,etc.