A method for measuring light softening of an azobenzene thin film through utilization of surface wrinkling

Abstract

The invention discloses a method for measuring light softening of an azobenzene thin film through utilization of surface wrinkling. Through utilization of surface wrinkling technology, a light softening effect, i.e. photoinduced elastic modulus reduction, of the azobenzene thin film is simply and conveniently measured through utilization of the surface wrinkling technology. Firstly, a tetrahydrofuran solution of an azobenzene polymer (PAzo) is coated in a spinning mode on a clean glass substrate. In a water-bath environment, the PAzo thin film is transferred to a stretched polydimethylsiloxane (PDMS) substrate to form a PDMS / PAzo soft and hard composite system. Retraction of the stretched polydimethylsiloxane (PDMS) is conducted under an illumination effect. Through control of irradiation light intensity, formation of wrinkles of a PDMS / PAzo double layer system can be regulated and controlled. Through measurement of a wrinkle period and the thickness of the PAzo film, an elastic modulus of the PAzo thin film can be obtained through calculating. The method is simple to operate and good in repeatability, avoids usage of complex and expensive apparatuses and tedious and complex theoretical simulation, and has a broad application prospect in tests of azobenzene thin film light softening.

Description

technical field [0001] The invention relates to a mechanical performance test of an azobenzene film, in particular to a surface wrinkling test for the light softening of an azobenzene film, that is, the reduction of the photoelastic modulus. Background technique [0002] Azobenzene has attracted widespread attention because of its unique photoresponsiveness. Among them, photoinduced mass transfer has been developed as a method to fabricate surface gratings. Under the irradiation of interference polarized light, the photo-induced cis-trans isomerization of the azobenzene group will lead to the macroscopic mass migration of the molecules on the surface of the azobenzene film. There have been many studies on the mechanism of mass transfer, but no unified conclusion has been obtained. Among them, the photosoftening theory believes that the progress of photoinduced cis-trans isomerization can reduce the modulus of the azobenzene film, increase the fluidity, and then cause macro...

AI Technical Summary

Problems solved by technology

The use of nanoprobes to measure the elastic modulus of materials requires the establishment of a strict mechanical model, and the selection of the model often leads to large differences in measurement results.

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