【作者】 刘志明；

【导师】 吴文健；

【作者基本信息】 国防科学技术大学 ， 材料科学与工程， 2009， 博士

【摘要】 本论文针对高光谱成像探测的现实威胁以及当前伪装技术面临的巨大困境,开展了基于植物叶片仿生的新型伪装材料研究工作。首先提出一种能够实现与植被环境“同色同谱”的植物叶片仿生伪装材料的模型。然后依据此模型,依次研究了叶绿体色素的光谱性质、叶绿体仿生色素微胶囊的制备和叶肉组织仿生多孔纤维素膜的制备。为拓展植物叶片仿生伪装材料的电磁对抗性能,还进一步开展了纳米金与纤维素之间进行杂化的研究。本论文的研究工作和成果为能够对抗高光谱成像探测、且具有一体化、宽频域伪装效能的植物叶片仿生伪装材料的开发和应用奠定了关键的物质基础。研究工作和主要结果如下:提出了植物叶片仿生伪装材料的全新理念,建立了以植物色素、水分和疏松多孔结构模拟植物叶片的仿生伪装材料模型。巧妙地开展了该模型的原理验证性实验,制备的含水和植物色素的人工多孔材料与梧桐多叶片叠加时的反射光谱相似度高达0.97548。基于对植物叶片中叶绿体色素的提取与分离技术和叶绿素的化学改性技术研究,首次制备出一种以铜叶绿素和叶黄素的复配色素为溶质的植物油溶液,该全仿生色素体系与叶绿体色素的四氯化碳溶液的光谱特征较为接近,且具有较高的光稳定性。进一步以该色素体系为芯材,以三聚氰胺—甲醛树脂为壁材,研究了采用原位聚合法制备叶绿体仿生色素微胶囊的工艺方法,确定了一组能够制备尺寸、形貌和光谱特征与叶绿体相似的色素微胶囊的制备工艺参数。研究了NMMO溶剂法制备叶肉组织仿生多孔纤维素膜的工艺方法,分析了影响纤维素膜多孔性的主要工艺因素,研究表明:多孔纤维素膜的厚度、平均孔洞尺寸等形态结构及其光谱反射率可以通过调节纤维素溶液中的共溶剂DMSO含量和旋转涂膜速度来控制,多孔纤维素膜的结晶度等结晶结构可通过调整凝固浴的组分来控制。确定了一种能够制备高性能叶肉组织仿生多孔纤维素膜的工艺方法。开展了有关纳米金/纤维素杂化膜的制备研究,成功地实现Frens法制备的纳米金与再生纤维素的杂化,发现了杂化膜中纳米金的含量与反应时间的指数关系和与所使用的金溶胶的浓度的线性关系。基于对纳米金与纤维素之间的杂化机理研究,建立了杂化反应“冠醚效应”模型。第一次采用无硫工艺制备了具有独特电学性质的纳米金/纤维素杂化导电膜材料,当纳米金含量在11.6210%以上时,该种杂化膜具有比较稳定的、类似于半导体二极管的电学性质。更多还原

【Abstract】 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%.更多还原