Preparation And Application Of High-performance Transparent Nacre-mimetic Composite Material

Transparent materials are widely used in industry,architecture,art and military fields.Conventional transparent materials include silica-based glasses and transparent polymers.However,silica-based glasses are prone to shattering and catastrophic failure,transparent polymers lack the hardness and modulus to resist wear and plastic deformation over long periods of use.These problems will affect the reliability of transparent materials in the long-term use process.For a long time,composite materials have been widely favored because of their ability to combine multiple properties of a single component material,especially some biological composites.In the shell of the Placuna placenta,for example,the internal arrangement of brittle calcium carbonate micro-platelets into a brick-and-mortar architecture enables it has excellent optical and mechanical properties,providing inspiration for the preparation of light weight and high strength transparent composites.At present,some high-performance transparent nacremimetic composites prepared by centrifugation,vacuum filtration and laser engraving have been reported.These approaches have resulted in increased composite fracture toughness and impact resistance,but reduces stiffness and strength.There is a general trade-off challenge that bioinspired composites have suffered from between mechanics,transparency,and fabrication scalability.To solve the above problems,an ion-diffusion-induced aligned self-assembly technology preparing skeleton with highly ordered orientation was developed.Subsequent infiltration of this porous scaffold generates a large-area high-performance bulk transparent nacremimetic composite,expanding the application of transparent composites.Firstly,a high strength and high toughness transparent nacre-mimetic composite was prepared by ion-diffusion-induced aligned self-assembly method.By inducing the ordered orientation of the glass flake through ion diffusion and directional gelation,a nacre-mimetic glass flake skeleton with aligned structure was assembled.A transparent nacre-mimetic composite was obtained by grafting a short chain of polymethyl methacrylate(PMMA)on the surface of the skeleton and infiltrating with resin.By carefully controlling the ion concentration,aspect ratio of glass flake and surface grafting time of skeleton,the nacre-mimetic composite shows high transmittance,high UV block percentage,high strength,high modulus,high toughness and high hardness.The mechanism of interface grafting forming semi-interpenetrating network to improve the properties of composite materials was proposed and verified.In addition,the inorganic content of the composite materials can be adjusted by uniaxial compression of the aligned glass flake skeleton before infiltrating with resin,so as to obtain the transparent nacre-mimetic composites with a wide range of optical and mechanical properties.The test of scratch resistance and thermal stability indicates its wide application potential.Secondly,a high modulus and high hardness transparent flexible nacre-mimetic composite film was prepared by ion-diffusion-induced aligned self-assembly method.Glass flakes were assembled into highly aligned structures under the action of calcium ion diffusion induction and gel fixation,and then the transparent flexible nacre-mimetic composite film was obtained after further infiltrating with resin.By carefully controlling the content of dopant and plasticizer,the flexible film has high transmittance,high UV block percentage,high modulus,high hardness and folding reliability over 5000 folding/unfolding cycles,indicating its application potential in flexible display.