Study On The Optical Properties And Swelling Behavior Of Colloidal Electrospun Fiber

Colloidal electrospinning can embed colloidal particles into electrospun fibers to obtain composite fiber membranes with special structure.However,the colloidal particles selected are mainly hard spheres such as polystyrene（PS）and silicon dioxide（Si O₂）,and the related studies are mainly focused on the morphology control of the fiber.In addition,the application and research fields of composite fiber membranes with different structures can be expanded by different treatments.In this paper,composite fiber membranes with blackberry-like structure and fiber-like structure were prepared by using temperature-sensitive poly（N-isopropylacrylamide-co-tert-butyl acrylate）（P（NIPAm-co-t BA））microgel as colloidal particles and polyacrylamide（PAAm）as carrier.The 2D microgel film with structural color was obtained by spraying the fiber membrane with blackberry-like structure,and the optical properties and structural evolution of the fiber membrane under the action of solvent were studied.the temperature-sensitive hydrogel fiber was obtained,and the changes of temperature sensitivity and swelling behavior of hydrogel fiber under different cross-linking density were investigated.The research work of this paper mainly includes the following two parts:In the first part,the fiber membrane with blackberry-like structure was obtained by electrospinning after mixing microgel and 13%PAAm solution at a mass ratio of 6:1.75%ethanol was sprayed on the surface of the fiber membrane to realize the transformation from blackberry-like structure to 2D microgel film,which can diffraction visible light and show structural color.The effects of ratio,spinning time,microgel size on the structure and optical properties of the sprayed microgel film were studied.Under the action of 75%ethanol,the blackberry-like aggregate dissolves and the microgel diffuses,and the 2D microgel film is obtained by self-assembly by immersion capillary force and spatial repulsion force.This microgel film can be used to prepare pressure sensors and various patterns.In the second part,the uniform and continuous fiber was obtained by mixing microgel and 20%PAAm solution at a mass ratio of 1:1 before electrospinning.The composite fiber membrane with certain mechanical strength,thermal stability and solvent resistance was obtained by crosslinking the fiber membrane with glutaraldehyde（GA）.The changes of temperature sensitivity and swelling degree of composite fiber membranes with different GA concent were investigated,and the cross-linking density and grid size of composite fiber membranes were calculated by equilibrium swelling method.The results showed that with the increase of GA content from 0.5%to 2.5%,the temperature sensitivity of the composite fiber membrane decreased from 0.28%to 0.06%,the grid size decreased from 28.2 nm to 12.4 nm,and the cross-linking density increased from 264.8?10^-5mol?cm^-3to 1044.2?10^-5mol?cm^-3.