| There are many animals and plants in nature that provide researchers with a continuous source of inspiration.For example,the concept of structural color originates from the bright colors presented by butterfly wings or bird feathers.The structural color is the result of the interaction between the microstructure of the material itself and light.At present,structural color materials are usually self-assembled by spherical colloidal particles with good monodispersity.However,it had been discovered that structural color films prepared only from spherical colloidal particles usually have disadvantages such as low color contrast and strong angle dependence.Hence researchers usually add black substance as a light absorbing agent to eliminate these disadvantages.Another bionic material boom comes from nature's superhydrophobic / superhydrophilic plants.At present,there are a lot of researches concentrate on the preparation of superhydrophobic materials and superhydrophilic materials.But there are few studies on the simultaneous superhydrophobic and superhydrophilic properties of the same material.Some researchers use sensitive materials to prepare materials that are both superhydrophobic / superhydrophilic.But the steps are complicated,and the raw materials are expensive or un-environmentally friendly.Based on the above problems,this article explores and researches the preparation of high-contrast,crack-free bionic photonic crystal structure color films and superhydrophobic / superhydrophilic convertible bionic photonic crystal films.(1)Based on nano-sized polystyrene spherical particles,a photonic crystal with a shortrange ordered structure was prepared with the aid of graphene oxide as a film-forming agent.Comparing with the photonic crystals prepared without graphite oxide-the assisted film formation,it is proved that graphene oxide can not only absorb light and enhance the color contrast of photonic crystals,but also reduce photonic crystal cracks.Optical photos show that the prepared photonic crystal film has high color contrast,no cracks,and no angle dependence.Experiments show that when the mixing volume ratio of PS dispersion(10 wt%)and GO solution(0.5 wt%)is 1: 1,the prepared structural color film has high color contrast,and exhibits no crack.(2)Based on a one-step dispersion polymerization method,micron-sized red blood celllike particles with protuberances on the surface(P-RBC)were prepared using divinylbenzene(DVB)as a crosslinking agent and styrene(St)as a monomer.The effects of the amount of DVB,the dropwise addition of St monomer,and the temperature of the reaction system on the morphology of the product were studied.Experiments show that when the amount of DVB is about 0.5 wt%,the mass ratio of styrene added to Stage ? and Stage ? is 15: 5,and the reaction system is heated up at the later stage,it is easiest to obtain P-RBC particles with stable surface morphology and good mono-dispersity.(3)Based on P-RBC particles,a single-layer film was prepared by the pulling method at the air-water interface.When the particle's cavity is upward,it appears as a super-hydrophilic film.When the particle's cavity is downward,after modified by fluorosilane,it appears as a super-hydrophobic film with strong water adhesion.The formation mechanisms of superhydrophobicity and super-hydrophilicity were also discussed.It was found to be closely related to the special morphology of P-RBC.Experiments show that when the particle's cavity is upward,the water contact angle of the super-hydrophilic film is only 3.8 °.When the particle's cavity is downward,the water contact angle of the super-hydrophobic film can be up to 163.6 °,and the water droplets on the surface are still attached to the surface after the film is turned 180 °. |
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