Study On The Preparation Methods And Optical Properties Of Structurally-colored Fibers And Fabrics

China has a significant influence on the textile industry, with an annual tradevolume that occupies25%of the world market. However, the economic benefits of thetextile dyeing and fishing industries do not cover the serious damages they cause to theenvironment. At present, the general Chinese public has become more aware of thehazards posed by the traditional dyeing and fishing industries, including drawbackssuch as high pollution, high energy consumption and high emissions. As a response tonational policies on energy-saving and emission-reduction, the textile coloring industryis required to develop a novel technology that is different from traditional chemicaldyeing processes. Therefore, we presented an idea that colors textiles based on physicalmethods that do not require the assistance of chemical dyes. We believe that thisenvironmentally conscious textile coloration strategy can reduce the pollution caused bythe traditional dyeing and finishing process.In this dissertation, we studied the preparation methods, optical properties, andmechanical strength of structurally-colored fibers and fabrics. The goal was to develop apreparation method of structurally-colored fibers and fabrics with actual applicationvalues and industrial production prospects. The following several aspects were mainlydiscussed:(1) Preparation of photonic crystal structurally-colored fibers through colloidalself-assemble in capillary: Structurally–colored fibers can be fabricated by soaking thecapillary tubes into PS microsphere dispersion through colloidal self-assembly. PSmicrospheres in the capillary tube formed a cylindrical colloidal crystal fiber as waterwas slowly evaporated. The colors of colloidal crystal fibers can be easily tuned byaltering the size of the PS microspheres. The reflective spectra in the radial direction were independent of the incident angle, while the spectra in the longitudinal directionnotably blue-shifted. The preparation method of colloidal self-assembly in capillary is atestament to the feasibility of preparing structurally-colored fibers, thus providing atheoretical basis for the subsequent studies.(2) Preparation of structurally-colored fibrous membrane via colloidalelectrospinning technology: Colloidal crystal fibers were fabricated rapidly on a largescale, using the electrospinning process. PVA clung to the surface of colloidalmicrospheres and worked as an adhesive agent to adhere PS microspheres, forminguniform colloidal crystal fibers. The obtained fibrous membrane was white due to thelow refractive index contrast between PVA and PS. Interestingly, the membraneappeared in colors as it was immersed in water. The membrane preserved the fibrousshape after water treatment. A large amount of PVA was dissolved in water and removedfrom the structure, increasing the reflective index contrast. The fibrous membraneexhibited isotropic color properties, which is independent of incident and observingangles. Therefore, the coloration of the membrane is similar to the color property indyes, which adapt to certain shades based on interpretations made by human vision.(3) Preparation of structurally-colored fibers through surface coatingtechnology: Inspired by the surface coating technology of optical fibers, we developeda new fabrication method for obtaining structurally-colored fibers by coating polymerfiber surfaces with colloidal crystal. The layers of colloidal microspheres showed anegative correlation with fiber lifting speed, and a positive correlation with the emulsionconcentration and fiber size. Interestingly, if number of colloidal layers reached10,further increasing the layers did not affect the color and reflective peaks of thestructurally-colored fiber. The fabricated structurally-colored PET fiber displayedexcellent mechanical property, which was possible via controlling the hardness ofmicrospheres and hydrophilicity of PET fiber.(4) Preparation of structurally-colored fibers with porous quasi-amorphousstructure through polymer phase separation: The structurally-colored fibers werefabricated rapidly and on a large scale, via electrospinning technology. During the process, the quasi-amorphous structure formed inside the fibers as a result of phaseseparation, as confirmed by SEM observation. The results of Fourier transform revealeda disordered bicontinuous porous structure with radial short-range order and long-rangedisorder. The obtained fibers exhibited isotropic color properties, which is independentto the incident and observing angles.(5) Preparation of structurally-colored fabrics through surface coatingtechnology: We fabricated structurally-colored fabrics on a large scale, though surfacecoating technology. The colorful fabric presented high brightness and saturation byadding inorganic nano SiO2/CB particles into soft polymer microsphere emulsion. Aperiodic structure with refractive index contrast was formed during the drying process.Due to the coffee-ring effect during the drying process of colloid emulsion, the color inlead edge was different from the middle portions. Colors of the obtained fabrics havegood stability when they were treated with water or oil. Excellent mechanical propertyof the structurally-colored fabric ensured the possibility of practical application.Coatings with different colors and shapes can be produced easily though screen-printingmode. This type of structurally-colored fabric has good practical value and prospect ofindustrialization.