Study Of The Plant Leaf Biomimetic Camouflage Materials

The study of a novel camouflage material based on the biomimetics of plant leaves was carried out as a countermeasure for the threat of hyperspectral imaging detecton and the dilemma of current camouflage technologies. At first, a model for the plant leaf biomimetic camouflage material having a potential property to be cocolor and cospectrum with plant enviroments was developed. Then, the studies of spectral characteristics of chloroplast pigments, the peparation of chloroplast biomimetic microcapsules of the pigment system and the preparation of mesophyll biomimetic porous cellulose fims were carried out in sequence. The conjugation of gold nanoparticles and cellulose was studied to explore the electromagnetic countermeasure ability of plant leaf biomimetic camouflage materials. The essential materials for the development and application of plant leaf biomimetic camouflage materials with integrated and broadly spectral camouflage abilities were supported by the research work and results in the dissertation. The research work and main results are shown below:The novel concept of plant leaf biomimetic camouflage materials was introduced at first. Then, the model of plant leaf biomimetic camouflage materials was developed by using plant pigments, water and porous structure to simulate plant leaves. The model validation was proved by using a well designed procedure, in which the reflectance spectrum of the porous material synthesized containing water and plant pigments exhibited a similarity index of 0.97548 with that of multiple leaves of the phonex tree.For the first time, a plant oil solution of the complex pigments of copper chlorophyll and lutein was prepared based on the technique studies of pigment extraction of chloroplasts in plant leaves and chemical modifications of chlorophyll. The completely biomimetic pigment solution showed similarly spectral characteristics with that of the carbon tetrachloride solution of chloroplast pigments and had a good stability under sunshine. Furthermore, the preparation of chloroplast biomimetic microcapsules of pigments was studied with the method of in situ polymerization by using the pigment solution as the core material and the resin of melamine-formaldehyde as the shell material. And one group of peparation parameters of the microcapsules of pigments was determined.The preparation of mesophyll biomimetic porous cellulose films was studied by using the NMMO solvent method, and influencing factors of the porous structures of cellulose films were analysized accordingly. The studies indicated that the structral properties, e.g., the thickness, the average size of pores, could be controlled by adjusting the concentration of dimethylsulfoxide and the rotating speed of coating, so did the spectral reflectance of the porous cellulose films. While, the crystalline properties, e.g., the crystalization index, of the porous cellulose films could be controlled by adjusting compositions of the coagulation bath. One preparation method of mesophyll biomimetic porous cellulose films with high performances was determined.The study about the hybrid films of gold nanoparticles and cellulose was carried out. The conjugation of gold nanoparticles prepared by using the Frens method and regenerated cellulose was achieved successfully. It was found that the concentration of gold nanoparticles in the hybrd films followed an exponential relationship with the reaction time and a linear relationship with the concentration of gold colloid used. The hybrid reaction model of crown ether effect was developed based on the miechanism study of the conjugation of gold nanoparticles and cellulose. For the first time, the conducting hybrid films of gold nanoparticles and cellulose with unique electronic properties were prepared by adopting an no―sulfur method, and they showed stable semiconducting diode electronic properites correspondingly with a concentration of gold nanoparticles above 11.6210%.