Preparation And Properties Of The Responsive Photonic Crystal Based Structurally Colored Fiber

Structural colored fibers are special fibers which have periodical structures in their inner or surface.Compared with traditional fibers,the color of the structural colored fiber derived from the interaction between periodical structures and light.With the development of smart clothing market,it will have critical demand for the fiber with special functions.The fabrication of structural colored fiber has attracted much attention due to their controllable structure and functional modification in recent decades.However,there are several limitations that districted the development of structural colored fibers.These limitations included that the periodical structures on the surface of fiber are easy to be broken,the structural colored fiber cannot response to external stimuli or the responsiveness are weakness.In order to solve those problems which existed in the fabrication of structural colored fibers,superparamagnetic Fe₃O₄@C colloidal particles were uses to fabricate structural colored fibers.Moreover,magnetic field induced one dimensional chain like structures were embedded in the inner of the fiber which made the structural color of the fiber more stable.Furthermore,the responsiveness of the structural colored fiber to various external stimuli,the relationship between optical properties of the fiber and external stimuli and the mechanisms of responsiveness were also studied.?1?Superparamagnetic Fe₃O₄@C colloidal particles were fabricated through a high-temperature hydrolysis reaction procedure.Three kinds of Fe₃O₄@C colloidal particles with the sizes of 138nm,158nm and 200nm were obtained by tuning hydrogen peroxide during the reaction process.These Fe₃O₄@C colloidal particles are uniform and can be dispersed in acetone,ethanol and DI water.On the other hand,magnetic field induced structural colored films were fabricated using photocurable suspensions.The films with different colors?red,green,blue?can display brilliant structural colors,which cannot be easily mimicked by pigments of chemical dyes.The reflection spectra peaks of red,green and blue films are 600,521 and 490 nm,respectively.Through combination of suspensions which contains Fe₃O₄@C with different sizes,a series of multi-colored films were fabricated.Furthermore,these structural colors can be patterned by photolithography and various structural colored patterns were shown in the article.The structural colored patterns could conceal or display its color according to changing of background which makes them hold significant potential application for security materials.Moreover,structural colored fiber with brilliant color was also fabricated in capillaries using photolithography.?2?A new type of photonic crystal PDMS fiber which exhibits tunable structural color upon exposure to external magnetic field is fabricated.The novel magnetic field responsive fiber was prepared from embedding ethylene glycol droplets?containing Fe₃O₄@C nanoparticles?into PDMS.In the presence of an external magnetic field,Fe₃O₄@C nanoparticles which dispersed in ethylene glycol droplets formed one dimensional chain-like structures along the magnetic field.As a result,the color of the fiber changes to yellow green.By contrast,when the magnetic field was removed,the color of the fiber will disappear and display its original color.Moreover,this novel PDMS fiber has good mechanical properties?60 MPa?and could keep its color under a fixed magnetic field no matter it was stretched or squeezed.?3?By using an external magnetic field,Fe₃O₄@C superparamagnetic colloidal particles formed one dimensional chain-like photonic crystal structures and embedded in polyacrylamide matrix.When the fiber was stretched/squeezed in the horizontal direction,the size of fiber would be reduced/increased in the vertical direction.As a result,the distance between each sphere in chain-like structures can reversibly changed with the elastic deformation of the matrix,and the structurally colored fiber displays brilliant colors from red to green as the mechanical strain changes which can be read by the naked eye clearly.The peak of reflection can be tuned from 637nm to 515 nm as a function of fiber extrusion or elongation.The novel structurally colored fiber is expected to have some important applications,such as the substitution of some fiber-based wearable electronic strain sensors because this fiber does not need any extra device to provide energy.?4?A structurally colored thermo-responsive fiber that exhibits tunable and reversible structural color due to temperature has been fabricated.The swelling fiber with red color can change to green as the temperature changing from 15-40 ^oC.The reflection peak can be tuned from 642 nm to 494 nm as the temperature changing.Therefore,this new structurally colored fiber which induced by magnetic field is expected to be useful for developing a new fibrous thermo-sensor because of its self-display color tuning capability.Moreover,the swelling ratio of the fiber in its length direction can reach 90 percent,which is higher than in its diameter direction?only 40 percent?,making the fiber could be used for the fibrous actuator according to its different elongation between its length and diameter direction.Furthermore,this new structurally colored fiber holds great potential for the development of smart textile devices with novel thermo-detections because it does not require any additional devices to provide energy.?5?Monodisperse magnetochromatic microspheres were synthesized in a microfluidic device.The size of microspheres can be controlled by the flow rates.In the experiment,we found that microspheres with larger sizes are more likely to form close packed structure.Furthermore,the microsphere can be constrained in the PVA film after the water soluble PVA solution was dried and display brilliant,tunable structural color according to external magnetic field.Moreover,microspheres can also be polymerized under UV light and have fixed structural color when using an external magnetic field during the polymerization.Calcium alginate fiber was fabricated through a new microfluidic device.Moreover,magnetic field responsive calcium alginate fibers were also prepared using sodium alginate and ETPTA?containing Fe₃O₄@C?mixed solution.