快速磁响应光子晶体的研究进展

响应性光子晶体是由不同介质周期性排列组成的带隙介质材料, 其中磁响应光子晶体因为能将外界磁场强弱变化快速表达为光学信号而在近几年发展迅速。本文从理论到具体工作综合论述了快速磁响应光子晶体的研究进展。首先基于布拉格衍射定律介绍了磁响应光子晶体在外部磁场的作用下产生光子带隙的原理, 然后系统总结了该类光子晶体的不同合成途径, 并在其能快速响应的基础上从稳定效果、形态尺寸控制和带隙分布等方面进行了综合分析, 最后从应用上探讨了具有快速磁响应特性的光子晶体对于传感器、防伪、彩色印刷等领域的潜力。     

化学所利用低黏附超疏水基材制备窄带隙聚合物光子晶体研究取得新进展

光子晶体以其特殊的周期结构和可以对光子传播进行调控的特性被称为“光学半导体”,被认为是未来光子工业的材料基础。近年来,光子晶体的结构、制备和光学特性研究受到全球范围内的高度关注,并在各类光学器件、光导纤维通讯和光子计算等领域呈现广阔的应用前景。在国家自然科学基金委、科技部和中国科学院的支持下,化学所有机固体和新材料实验室的科研人员针对目前光子晶体制备和应用开展了广泛研究。他们通过结构设计,制备了具有硬核一软壳结构的乳胶粒,制备了具有特殊紧密堆积结构的高强度光子晶体。     

光子晶体传感器研究进展

部分生物体呈现的颜色具有与角度有关,不易褪色的特点。光子晶体是一种介电常数随空间周期性变化的新型光学微结构材料,其最根本特征是具有光子禁带。本文介绍了光子晶体的结构性能特点及自组装制备方法如模板法、刻蚀法等。也重点阐述了光子晶体在光、电、力、热及化学物质检测方面的应用,体现了光子晶体在传感器应用上的优势。文末对光子晶体今后的研究方向做了展望。     

油性介质中组装二氧化硅胶体晶体薄膜

报道厂一种由粒径大于700nm的SiO2微球组装胶体晶体薄膜的方法。以一种密度较大的疏水性有机物替代水或醇类为分散剂,通过对SiO2微球表面进行疏水性处理改善其在油性介质中的分散性,采用改进的垂直沉积法在油性分散剂中制备SiO2胶体晶体。用扫描电子显微镜、红外光谱仪和紫外－可见光谱仪对SiO2胶体晶体薄膜的形貌、结构和光学性能进行了观察测试。结果表明;较大密度的分散剂能有效降低SiO2微球的沉降速度,组装成直径在700～2000nm范围的SiO2微球的胶体晶体。获得的SiO2光子晶体具有长程有序结构,并在近红外区具有显著的光子频率带隙。     

相分离法制备超疏水丙烯酸聚氨酯及防伪应用

以丙烯酸聚氨酯作为柔顺单体、丙烯酸十八酯作为可逆结晶相、三羟甲基丙烷三丙烯酸酯为交联剂,形成三维化学交联结构,通过相分离法制备了一种疏水薄膜。通过冷场发射扫描电镜及接触角测试表明,材料表面呈现片状堆积结构,尺寸在1μm~5μm左右。将超疏水表面进行热处理后,材料在相变温度调控下,可以实现超疏水到亲水的转换。同时,通过相变可控制薄膜的透明度,引起光学衍射特征变化,可应用于光子晶体图案化防伪领域。     

同步拉伸速率对双向拉伸聚乙烯薄膜结晶结构及性能的影响

实验采用双向拉伸聚乙烯(BOPE)原料线型低密度聚乙烯(LLDPE),用同步双向拉伸的方法制备BOPE薄膜,研究了双向拉伸过程中拉伸速率对薄膜结构和性能的影响。使用偏光显微镜(PLM)和差示扫描量热法(DSC)对未拉伸聚乙烯流延片的结晶形貌和热性能进行了研究。研究了不同拉伸速率下机器方向(MD)拉伸力的实时变化趋势,用DSC表征了不同BOPE薄膜样品的热性能。发现拉伸速率影响拉伸过程中聚乙烯晶体和分子结构及最终样品的结晶度和晶片厚度分布。实验研究了BOPE薄膜的力学和光学性能,分析了薄膜的宏观性能和分子结构之间的关系。实验结果表明,较高的拉伸速率有利于薄膜性能的提高。     

原料结构对BOPP薄膜拉伸工艺及性能的影响

选取5种具有典型结构的双向拉伸聚丙烯(BOPP)薄膜专用料,研究了该专用料分子结构对BOPP薄膜拉伸工艺及性能的影响。结果表明:共聚组分含量较高的F280B原料具有较宽的拉伸工艺窗口,其薄膜的光学性能较好,但力学性能相对较低;薄膜性能受原料分子链等规度和共聚单体含量等因素的影响。     

基于同步辐射技术的高分子多尺度结构薄膜拉伸加工物理研究

基于自制溶液拉伸装置与同步辐射技术,对不同温度状态下聚乙烯醇薄膜水中拉伸诱导结构演变,及其纤维化过程进行了深入探究。通过拉力传感器所获拉伸过程的应力应变曲线以力学平台起点、终点、应变硬化点作为界限点进行区间划分。宽角X射线衍射结果表明,在①～③区间,出现了拉伸诱导聚乙烯醇晶体熔融过程。小角X射线散射结果表明,拉伸诱导片晶-纳米纤维结构转换过程出现在②区间初始,且此过程即熔融-重构过程。在③区间,在含量不断增多趋势下,纳米纤维结构开始发生周期性排列,邻纤维间距大约在14～18nm。而拉伸温度上升,可显著提高纳米纤维结构排列整体性与完善性,此纤维结构有助于优化偏光膜产品结构均衡化与光学性能。     

高熵化透明陶瓷研究进展

透明陶瓷作为一种具有优异理化性能的结构功能一体化材料,多年来已在诸多领域替代传统透明材料进行使用,如固态照明、高功率固体激光器、高密度屏蔽窗口、光学元件及光电器件等,而近年来高熵陶瓷的研究为透明陶瓷的进一步发展提供新思路。透明陶瓷高熵化使其可利用高的构型熵来改善或提升其力、热、光学等性能,从而实现更多领域、更深层次的功能化应用。综述了作为高熵透明陶瓷潜在结构的几种陶瓷体系的结构、制备、性能和应用进展,详细介绍了当前透明陶瓷高熵化研究的现况,并对其未来的发展及应用进行展望。     

共聚组分含量对BOPP薄膜性能的影响

采用具有不同共聚组分含量的PP原料,进行双向拉伸成型BOPP薄膜,并对薄膜拉伸过程中的拉伸力变化,以及薄膜性能进行了测试和研究.结果表明,随原料中共聚组分含量的增大,薄膜的成型拉伸力有所下降,薄膜的拉伸模量、强度等力学性能相应降低,而薄膜的雾度、光泽度等光学性能明显改善.     

Enhanced Visible Light Absorption in a Photocatalytic Thin Film from a Decoupled Photonic Crystal

The optical and photocatalytic properties of a photonic crystal structure were examined to elucidate the origin of the enhanced visible light absorption from semiconductor photonic crystals. Both an enhancement in visible light absorption and an increase of the photoactivity of the semiconductor photocatalyst were found when a photonic crystal layer was decoupled from the photocatalytic film. The decoupling clearly shows that the optical enhancement arose from the dielectric mirror effect of the photonic crystal. As such, the enhancement was maximized by matching the high light absorbance region of photocatalytic semiconductors with the characteristic photonic band gap of the decoupled photonic crystal layer under various illumination conditions. For enhanced visible light photocatalytic activity, the decoupled photonic crystal layer does not have to be made from the same light-harvesting materials, but can be synthesized by a wide range of materials for ease of the fabrication process.     

超快激光在玻璃内部直写纳米晶及其应用

超快激光直写技术由于其灵活性、高效性和良好的方向性,可以三维选择性地在材料内部进行加工,被广泛应用于玻璃的微晶化及其器件的制备中,在光储存、波导激光器、光子电路和集成光子芯片等领域有着广泛的应用前景。本文简要概述了超快激光在玻璃内部诱导析晶的原理,晶态/非晶态自组织周期性结构的形成机制,以及超快激光在玻璃三维空间中诱导析晶的最新研究进展,总结了通过控制激光参数和玻璃成分等实现对结晶形态、结构及光学性质调控的相关研究,并对所直写的微纳结构在非线性器件、光储存、激光器等领域的应用和发展方向进行了概述与展望。     

光学透明胶膜CEF0807的性能研究

光学透明胶膜(CEF0807)是一种用于粘接光学透明元件的特种PSA(压敏胶),其对被粘基材的力学性能、透光性能、雾度、色彩失真度和可靠性等影响很大。研究结果表明:CEF0807是一种粘接性能优异的压敏胶,其对玻璃、聚碳酸酯(PC)、聚甲基丙烯酸甲酯(PMMA)和聚对苯二甲酸乙二醇酯(PET)等基材的180°剥离强度分别为141、117、108、103 N/100 mm;CEF0807具有优异的光学性能,其透光率为94.3%,而雾度和色差(ΔE)仅分别为0.80%和1.48;CEF0807经环境可靠性测试后性能优异,非常适合于光学元件、光学视窗等材料的粘接。     

TiO2薄膜纳米改性搪瓷表面光泽影响的研究

采用溶胶-凝胶法制得稳定的淡黄色透明TiO2溶胶溶液,通过浸渍提拉法在搪瓷表面制备TiO2薄膜。研究了在搪瓷表面涂有不同层数的TiO2薄膜对其光泽度的影响,同时还采用XRD和SEM分析了搪瓷表面TiO2薄膜的晶体结构和显微形貌。结果表明,薄膜在400℃热处理1 h后,具有完整的锐钛矿相和良好的光学性能;不同层数的TiO2薄膜对搪瓷表面的光泽度产生了显著的影响。     

水溶液中均匀硫化镉微球的制备及其在结构色中的应用

均匀的硫化镉（CdS）微球具有较高的折射率,由其组成的光子晶体颜色亮丽,具有低角度依存性,近年来在结构生色领域被广泛应用。但是,目前较为成熟的合成均匀硫化镉微球的方法存在有机溶剂的大量使用和高温能耗大等问题。因此,设计了一种在水溶液中合成均匀硫化镉微球的绿色合成方法,通过受控注射的方式辅助进料,解决了金属盐前驱体在水中水解速度过快导致微球生长不平衡的问题。同时,受控注射的方式可以更有利于控制体系中二价镉的浓度,成功地合成出180~410 nm的均匀硫化镉微球。进一步通过水平诱导组装的方式构筑了以不同粒径的硫化镉微球为基元的三维光子晶体结构。这种光子晶体薄膜展示出亮丽、低角度依存的结构色,更利于结构色在颜色显示等领域的应用。     

Structural color films with lotus effects, superhydrophilicity, and tunable stop-bands

The structural blue color of a Morpho butterfly originates from the diffraction of light and interference effects due to the presence of the microstructures on the wing of the butterfly. Structural color on the surface of a damselfish reversibly changes between green and blue. Inspired by these creatures, we have been trying to prepare high-quality and functional structural color films. We describe our efforts in this Account. A useful technique to prepare such structural color films in colloidal solution is a "lifting" method, which allows us to quickly fabricate brilliant colloidal crystal films. The thicknesses of the films can be controlled by precisely adjusting the particle concentration and the lifting speed. Moreover, in order to prepare a complicated structure, we have used template methods. Indeed, we have successfully prepared the inverse structure of the wing of a Morpho butterfly with this technique. Initially, however, our structural color films had a whitish appearance due to the scattering of light by defects in the colloidal crystal film. Later, we were able to prepare a non-whitish structural color film by doping an appropriate dye in the colloidal particles to absorb the scattering light. In addition to the structural blue color, the wing of the Morpho butterfly has superhydrophobic properties. According to Wenzel's equation, the hydrophobic and hydrophilic properties are enhanced when the roughness of the hydrophobic and hydrophilic surface is increased, respectively. Based on this mechanism, we have successfully prepared structural color films with superhydrophobic properties, as well as with superhydrophilic properties. Another important property that can be seen in nature is tunable structural color, such as the color change that can be seen on the surface of a damselfish. In order to mimic such color change, we have developed several tunable structural color films. In particular, we have successfully prepared phototunable photonic crystals using photoresponsive azobenzene derivatives. In order to apply these structural color films, we developed a technique for patterning them by taking advantage of the wettability of the substrate surface. These materials can be used in the future for self-cleaning pigments and tunable photonic crystals.     

Preparation of flexible and transparent SMA films by simple composite with MBS potential for negative birefringence compensator

The brittleness of poly(styrene maleic anhydride) (SMA) was improved by compositing with elastic poly(methyl methacrylate‐butadiene‐styrene) (MBS) to develop it into optical film. Transparent and flexible SMA films were prepared, and the flexibility of them was checked by folding endurance test and folding bend. The transparence of SMAMBS films were proved by the transmittance and haze measurements. In actual view, the letters could be clearly observed while they were covered by prepared films. The thermal stability of them was confirmed by DSC and TGA analysis. These physical properties of films are comparable to that of polycarbonate which is widely used as optical film. Besides of these, mechanical and fracture properties of them were found to be also suitable for this purpose. Furthermore, negative birefringence could be obtained by orientationally stretching them. Such results indicate that, films prepared from composites are competent for negative birefringence optical compensator in the field of liquid crystal display. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

线状缺陷态光子晶格光学特性的实验研究

利用实验的方法对自散焦LiNbO3∶Fe晶体中构造的缺陷态光子晶格光学性质进行了研究。实验表明影响缺陷态光子晶格光学性质的因素很多,如有无格子、晶格周期的不同,还有缺陷在晶格中的角度和缺陷间晶格列数都对其光学性质有很大的影响。文中同时对实验现象也做了初步的理论解释,这对光子晶格的制作与应用有一定的指导意义。     

Mechanical nondiscoloring and antistretching photonic crystal films based on Zn2+ coordination and hydroxypropyl methylcellulose

Mechanical nondiscoloring and antistretching photonic crystal (PC) films, especially those with stable structure colors during deformation, have great potential applications in wearable display devices, decoration, and packaging. Here, PC films with antistretching and invariant structural colors during deformation were prepared, by combining Zn²⁺ coordinated elastic material and hydroxypropyl methylcellulose (HPMC) with polystyrene@silica (PS@SiO₂) colloidal crystals. The PC films release energy by forming local fractures at a microscopic level during the straining process but the lattice spacing and effective refractive index of the local array do not change. According to the Bragg law, the structure color remains unchanged. The introduction of HPMC gave the PC films excellent tensile properties, and the maximum tensile strength reached 10 MPa. And after 100 times of stretching, bending and compression cycles, the structural color remained unchanged.     

Electrospinning of biopolymer nanofibers encapsulated with functional nanoparticles toward core-shell fluorescence encoding

Photochromism has been an efficient approach to improve authenticity of commercial products. In order to prepare an authentication nanofibrous film with mechanical reliability, it has been crucial to improve the engineering production route of the authentication materials. Herein, we electrospun photoluminescent nanofibrous film with a fiber diameter of 50–200 nm from the environmentally-friendly polylactic acid embedded with nanoparticles of rare-earth activated strontium aluminate (NRESA; 10–15 nm). The created nanocomposite film was colorless in daylight, and became an intense green in ultraviolet light. The strontium aluminate photochromic agent must be applied in the nanoparticle form to ensure film transparency by enhancing its dispersion without aggregation in the electrospun polylactic acid nanofiber bulk. An emission peak was observed at 518 nm after excitation of the pigment-polylactic acid nanofibers at 365 nm. Raising NRESA ratio increased the hydrophobic properties of the pigment-polylactic acid nanofibers without changing their visual or mechanical properties. The transparent films showed high photochromic reversibility without exhaustion under numerous exposure cycles of ultraviolet light and darkness. The nanofibrous mats were elastic and flexible. The current technique is an effective strategy for making a variety of anti-counterfeiting substances.