【作者】 薛飞；

【导师】 孟子晖；

【作者基本信息】 北京理工大学 ， 应用化学， 2014， 博士

【摘要】 将纳米尺度的结构单元进行可控的自组装，使其成为有活性的纳米结构功能材料是一项巨大的技术挑战。光子晶体是两种以上折光指数不同的材料在空间按照一定的周期顺序排列所形成的有序结构功能材料。其结构单元处于可见光波长范围，存在光学禁带，可以调制光的传播，是一种新兴的纳米结构功能材料，在许多方面都存在应用价值。光子晶体结构的制备是光子晶体研究领域的重要研究方向之一。目前，三维光子晶体结构制备的研究较为深入，但是对二维光子晶体制备的研究相对较少。光子晶体异质结构丰富了光子晶体的光学性质，但是此方面的研究大多集中于三维光子晶体结构上，而且存在制备周期长，有序度不容易控制等问题。近年来，界面自组装为二维光子晶体的制备提供了有效方法，但是却需要精细操作，较难控制。将刺激响应性材料与光子晶体结构相结合，可以发展出具有响应速度快，信号自表达等性质的光子晶体生化传感材料。目前，光子晶体生化传感应用方面仍然存在一些不足和可改进之处：首先，在光子晶体传感材料选择性上仍有提高的空间。其次，常规光子晶体生化传感器是以三维光子晶体为模板制备得到的反蛋白石结构材料，制备步骤较为繁琐。再次，三维光子晶体传感材料的研究较为广泛，但是在二维光子晶体传感应用方面的研究较少。另外，通常刺激响应性材料为功能化的水凝胶材料，所能检测的目标物种类较为有限。针对上述研究现状和发展瓶颈，本文从光子晶体制备和光子晶体生化传感应用两方面入手进行了较为深入的研究。在光子晶体结构制备方面，本文首先制备了光学禁带处于可见光波区的三维光子晶体和二维光子晶体；然后，利用层层转移沉积的方法制备得到了二维光子晶体异质结构；最后利用聚甲基丙烯酸甲酯微球在甲苯中的单分散性发展出一种快速制备二维光子晶体自支撑膜的方法。在光子晶体生化传感应用方面，本文先后制备了对葡萄糖和内分泌干扰物对硝基苯酚具有高选择性识别的三维光子晶体传感材料。然后，将二维光子晶体结构引入智能响应材料中，发展出了对葡萄糖、pH和高级脂肪酸具有快速、比色（colorimetric）响应的二维光子晶体传感材料。具体研究内容和结果如下：1）制备了单分散好、粒径在一定范围可控的聚甲基丙烯酸甲酯（PMMA）、聚苯乙烯（PS）、二氧化硅（SiO2）胶体微球，并通过垂直沉降自组装方法将胶体微球制备成三维光子晶体。所得到的光子晶体结构高度有序，布拉格衍射峰强度高，结构色单色性好，而且处于可见光波区。2）制备了大粒径（>500nm）的PS和PMMA胶体微球，并通过尖端导流自组装的方法在空气/水界面制备了二维光子晶体。通过布拉格衍射光谱检测、德拜衍射环表征、结构色观察等手段检测了二维光子晶体的光学特性。在此基础之上，采用反复转移沉积的方法将不同粒径的PMMA微球有序组装在一起，形成了二维光子晶体异质结构。研究表明，所得到的光子晶体异质结构的光子禁带得到了有效的扩展，而且不同层之间紧密堆砌；布拉格衍射、德拜环衍射和结构色等光学性质近似等同于内部每层二维光子晶体的光学性质叠加。3）将PMMA胶体微球分散于甲苯/乙醚混合溶液中，在一定时间内滴在水面，可以制备得到单层的胶体晶体薄膜。所制备的胶体晶体膜具有良好的机械强度，虽然厚度只有几十纳米，但自支撑面积可达1cm2。该PMMA膜具有二维光子晶体的光学性质，有望在分析和分离等领域得到应用。4）将分子印迹技术与光子晶体技术相结合发展出了分子印迹光子晶体传感材料。首先以三维PMMA光子晶体为模板，制备出具有反蛋石结构的分子印迹光子晶体凝胶。在pH9.6的缓冲液环境中，光子晶体凝胶实现了葡萄糖的快速高选择性响应（检测限为1mM）。另外，我们制备了分子印迹胶体微球，并将微球自组装得到胶体晶体，通过胶带粘贴固定，得到分子印迹胶体晶体，可用于内分泌干扰物对硝基苯酚的检测。结果表明，30mM的对硝基苯酚引起分子印迹胶体晶体50nm的红移，检测限为1mM。随着目标物浓度的增加，印迹胶体晶体的结构色由绿色变为红色，实现了比色检测。5）将PS二维光子晶体包埋在苯硼酸功能化的水凝胶薄膜中，制备得到了二维光子晶体凝胶，实现了对葡萄糖的高选择性比色响应。研究表明，在生理离子强度的环境下，二维光子晶体凝胶对葡萄糖的响应覆盖生理血糖浓度范围，检测限为0.1mM，响应时间为3min。6）以PS二维胶体晶体为模板，填充聚甲基丙烯酸羟乙酯-丙烯酸凝胶，并除掉模板得到表面具有单层规则孔洞的二维反蛋白石光子晶体凝胶，在pH2-7范围内具有快速响应（<3min）。凝胶对pH的体积响应转化为二维光子晶体的德拜衍射环的尺寸和结构色的变化，检测手段成本低，而且简单可靠。7）为了扩展响应性凝胶的检测目标物种类，我们创新性地将蛋白质交联成凝胶，用于光子晶体传感材料。我们选用牛血清蛋白（BSA）进行验证性实验。利用戊二醛为交联剂，结合PS二维光子晶体，制备得到BSA二维光子晶体凝胶。结果表明，所制备的BSA凝胶透明且机械强度较好。由于BSA在血液中具有运输脂肪酸到肝脏的功能，因此BSA凝胶对月桂酸具有响应。总之，光子晶体结构独特的光学性质和光子晶体传感材料的信号自表达能力引起了人们的广泛关注，我们希望上述工作为光子晶体功能材料的有效制备提供方法借鉴，并拓展该种材料在生化传感体系中的应用。更多还原

【Abstract】 The integration of nanoscale building blocks with well-controlled architectures intoactive nanostructured functional materials is a great technical challenge. Photonic crystalsare an emerging type of nano structural functional materials that possess periodicity in therefractive index. Due to the periodicity in dielectric materials, photonic crystal materialspossess a photonic band gap and special light manipulation properties. As a new typeadvanced functional polymers, photonic crystals demonstrate wide application in opticalsensing materials and optical devices.One important research direction of photonic crystal is the preparation of photoniccrystal structures. Three-dimensional (3D) photonic crystal fabrication has been widelyinvestigated. However, the formation of two-dimensional (2D) photonic crystals has beenreported only until recent years. For instance, most photonic crystal heterostructures whichcan enrich the optical properties are prepared based on3D photonic crystals. However, thepreparation procedure is time-consuming and the ordering is likely to be damaged. For2Dphotonic crystal preparation, even though the interface self-assembly affords an efficientmethod, it needs careful operation.Another important research area is photonic crystal structure-based stimuli-responsivematerial by combining intelligent material with photonic crystal. The raid response andself-reporting properties make these photonic crystal sensing materials becomingincreasingly attractive in the area of chemical and biological sensing. Unfortunately, thereare still some problem exist. First, the selectivity of many photonic crystal bio-chemicalsensors are not desirable. Second, traditional photonic crystal sensing materials are inverseopal structures prepared by using3D photonic crystals as templates. These preparationprocedures are tedious. Third,2D photonic crystal sensing materials are not studied widelyas3D photonic crystals yet. In addition, the target analytes are limited due to that most ofthe materials are based on functional hydrogels.In order to solve the problems encountered in the fabrication of photonic crystals andapplication of responsive photonic materials, in this thesis, we are focusing on the fabrication of photonic crystals and development of photonic crystal sensing materials. Inphotonic crystal preparation, firstly, several3D and2D photonic crystals with optical bandin visible region were fabricated; secondly, photonic crystal heterostructures based on2Dphotonic crystal were prepared; finally, a simple method for the preparation of free-standing2D colloidal crystal film were developed. In photonic crystal responsive materials, firstly,glucose responsive inverse opal hydrogel films and p-nitrophenol responsive colloidalcrystal films with high selectivity were developed; secondly, several photonic crystalsensing materials based on2D photonic crystal were prepared. These2D photonic crystalsensors exhibit fast and colorimetric response to glucose, pH, and fatty acid, respectively.The main contents and results are summarized as follows:1) Monodisperse size-controlled poly methyl methacrylate (PMMA), poly styrene (PS)and silica colloidal microspheres were fabricated, and formed3D colloidal crystals usingvertical deposition self-assembly methods. The resulting3D photonic crystals with wellordering and good monochromaticity exhibit strong Bragg diffraction in the visible region.2) Larger size (>500nm) PS and PMMA colloidal microspheres were prepared, andassembled into2D photonic crystals at the air/water interface by a needle tip flow method.The Bragg diffraction, Debye diffraction ring detection and structural color were used tocharacterize the optical property of these photonic crystals. Further more, two-and three-layer colloidal crystal heterostructures (CCHs) based on2D photonic crystals werefabricated by successive deposition of2D PMMA colloidal monolayer colloidal arrays ofdifferent particle sizes.The structure and optical properties of2D CCHs were characterizedby SEM, reflectance spectra, Debye diffraction rings and their diffracted wavelengths. Thelayers maintain their spacing and ordering and the2D CCHs diffraction measurementssuggest that the optical properties of the composite colloidal heterostructures arise mainlyfrom the independent diffraction of the individual2D colloidal arrays.3) A novel method to fabricate thin free-standing2D PMMA colloidal crystal filmswas developed. PMMA colloids were dispersed into methylbenzene/diethyl ether solution,and then one droplet of the suspension solution was dropped on the water surface. ThePMMA dispersion spreads on water surface and self-assembled into a thin2D colloidal crystal free-standing film. The obtained2D colloidal crystal film is mechanically strong andcan be transferred to mental mesh (~1cm2). In addition, it efficiently diffracts light as2Dphotonic crystal does which is promising in separation and analyticaltechnique.4) A glucose-sensitive inverse opal hydrogel based on the combination of photoniccrystal templating and molecular imprinting technique were fabricated. At pH9.6, theunique3D ordered porous hydrogel revealed selective optical changes in response toglucose concentration with a detection limit of1mM. In addition, by a self-assemblyapproach using p-nitrophenol (PNP) imprinted colloidal spheres, PNP responsive colloidalcrystal was prepared. The ordering of the colloidal crystal was stabilized by attaching thesecolloidal crystal onto an adhensive tape. The results showed that the diffraction wavelengthof the imprinted colloidal crystal red-shifted more than50nm in response to30mM PNPwith a detection limit of1mM. Color change due to the diffraction light shift can beobserved.5) A novel2D photonic crystal sensing material for the visual detection of glucosewith high selectivity is developed.PS2D colloidal crystal is embedded in a phenylboronicacid (PBA) functionalized hydrogel film to diffract light to sensitively report on thehydrogel surface area. The2D photonic crystal sensor exhibits significant sensitivityforglucose across the entire human physiological glucose range at the physiological ionicstrength with a detection limit of0.1mM and response time of3min.6) A hydrogel film with a highly ordered macropore monolayer on its surface bytemplate photo-polymerization of2-hydroxethyl methacrylate-co-acrylicacid hydrogelmonomers on a2D PS colloidal crystal were fabricated. The2D inverse opal hydrogelshowed pH response across pH2to7with response time of3min. Debye diffraction ringdetection and color change detection method which are easy and low-cost were used tocharacterize the hydrogel sensor.7) In order to expand the target analytes, a proof-of-concept for introducing proteinhydrogel into photonic crystal sensing material to expand the range of analytes weredemonstrated. Bovine serum albumin (BSA) isa globular protein that functions asbloodstreamcarriers of hydrophobes such as fatty acids. This novel2D photonic crystal protein hydrogel was prepared by attaching2D colloidal crystal onto pure BSA hydrogels.The2D photonic crystal BSA hydrogel is transparent and has desired mechanical strength.The binding ofsodium dodecanoateto the protein hydrogel swells the hydrogel volumecausing shifts inthe diffraction.Fabrication of photonic crystal and their application in bio-chemical sensing materialhave attracted considerable interest due to their unique optical properties and functionality.We expect that the work presented in this thesis could provide a convenient and efficientstrategy for the development of functional materials towards bio-chemical sensingapplications.更多还原