Ordered Block Copolymer Thin Films Studied by Guided-Wave Depolarized Light Scattering

导波去偏光散射研究有序嵌段共聚物薄膜

• 批准号: 0514422
• 负责人: Bruce Garetz
• 金额: $ 39万
• 依托单位: Polytechnic University of New York
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-01 至 2009-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0514422&HistoricalAwards=false
• 关键词: Ordered; Block; Copolymer; Thin; Films

TECHNICAL EXPLANATIONThis proposal seeks funds to continue the development of a novel analytical technique forcharacterizing the organization of anisotropic nanostructures (e.g. lamellae and cylinders)in optically transparent block copolymer thin films. Quantitative measurement oforganization is critical for many proposed applications of nanotechnology, ranging fromfuel cells to optoelectronic devices. GWDLS allows the low-cost, non-destructive, realtimemeasurement of order formation and defect density in optically transparent thinfilms. Among methods for thin-film characterization, GWDLS is unique in that itprovides an average measure of defect density over macroscopic length scales (~1 cm) ina film. Position-space methods for studying defect structure, such as atomic forcemicroscopy (AFM) and scanning electron microscopy (SEM), can measure local defectstructure, but are impractical for obtaining statistical averages over macroscopic regions.The GWDLS technique involves the coupling of a laser beam into a guided mode of aplanar optical waveguide consisting of a block copolymer film deposited on a lowrefractive index substrate. Light coupled into a guided mode propagates through the filmby total internal reflection. As the light interacts with anisotropic grains in the film, itgenerates depolarized scattered light which propagates in guided modes with orthogonalpolarization. This scattered light is coupled out of the film and detected. In the proposedwork, we will (1) Modify the current GWDLS apparatus to study the propagation ofpolarized light in a symmetric silica-polymer-silica sample environment using a gratingcoupler. (2) Develop a theoretical model for quantifying the relationship between theGWDLS signal and statistical properties of randomly oriented and partially orientedgrains in thin films. (3) Use GWDLS to determine the order-disorder transitiontemperature of block copolymer thin films with both lamellar and cylindrical order. (4)Measure the kinetics of order formation in thin films after quenching from the disorderedto the ordered state. (5) Obtain a quantitative measure of the average grain size bycomparing the measured signal with theoretical predictions. All of the polymers andsubstrates required for the project will be prepared by the students. Completecharacterization of the films using complementary techniques such as AFM, SEM, andSIMS will be carried out. NON-TECHNICAL EXPLANATIONBalsara will serve as a faculty instructor in the Math and Science Summer Academywhich brings approximately 60 students from local high schools to the University campusto participate in a six-week enrichment program in math and science. Typically half ofthe participants are African American, one quarter Chicano, and the remaining quarterAsian, Caucasian, Filipino and Latino. Garetz will continue his 7-year involvement withPolytechnic University's David Packard Center for Technology and EducationalAlliances. His activities include conducting workshops at the New York CityScience/Technology Forum where 500 students from New York City public schoolscome to Poly for a full-day program where they meet outstanding engineers andtechnologists representing centers of higher education, hospitals, and corporations. Thegraduate students working on this project will receive multidisciplinary scientific trainingencompassing synthesis and characterization of polymers, optics, lithography, and nonequilibriumthermodynamics. Their background in characterization and manipulatingnanostructured thin films is relevant for current and future technologies.

技术说明本提案寻求资金继续开发一种新颖的分析技术，用于表征光学透明嵌段共聚物薄膜中各向异性纳米结构（例如薄片和圆柱体）的组织。组织的定量测量对于纳米技术的许多拟议应用（从燃料电池到光电器件）至关重要。 GWDLS 可以低成本、非破坏性地实时测量光学透明薄膜中的有序形成和缺陷密度。在薄膜表征方法中，GWDLS 的独特之处在于它提供了薄膜中宏观长度尺度（~1 cm）缺陷密度的平均测量。用于研究缺陷结构的位置空间方法，例如原子力显微镜 (AFM) 和扫描电子显微镜 (SEM)，可以测量局部缺陷结构，但对于获得宏观区域的统计平均值是不切实际的。GWDLS 技术涉及将激光束耦合到由嵌段共聚物薄膜组成的平面光波导的引导模式中 沉积在低折射率基底上。耦合成导模的光通过全内反射穿过薄膜传播。当光与薄膜中的各向异性颗粒相互作用时，会产生去偏振散射光，该光以正交偏振的导模传播。这种散射光从薄膜中耦合出来并被检测到。在拟议的工作中，我们将（1）修改当前的GWDLS设备，使用光栅耦合器研究对称二氧化硅-聚合物-二氧化硅样品环境中偏振光的传播。 (2) 建立一个理论模型来量化GWDLS信号与薄膜中随机取向和部分取向颗粒的统计特性之间的关系。 (3) 利用GWDLS测定层状和柱状嵌段共聚物薄膜的有序-无序转变温度。 (4)测量淬火后薄膜从无序态到有序态有序形成的动力学。 (5) 通过将测量信号与理论预测进行比较，获得平均晶粒尺寸的定量测量值。该项目所需的所有聚合物和基材将由学生准备。将使用 AFM、SEM 和 SIMS 等补充技术对薄膜进行完整表征。 非技术说明巴尔萨拉将担任数学和科学暑期学院的讲师，该学院将吸引约 60 名来自当地高中的学生来到大学校园，参加为期六周的数学和科学强化课程。通常一半的参与者是非裔美国人，四分之一是奇卡诺人，剩下的四分之一是亚洲人、白人、菲律宾人和拉丁裔。加雷茨将继续参与理工大学大卫帕卡德技术和教育联盟中心长达七年的工作。他的活动包括在纽约市科学/技术论坛举办研讨会，来自纽约市公立学校的 500 名学生来到 Poly 参加全日制课程，在那里他们会见代表高等教育中心、医院和企业的杰出工程师和技术专家。从事该项目的研究生将接受多学科科学培训，包括聚合物、光学、光刻和非平衡热力学的合成和表征。他们在表征和操纵纳米结构薄膜方面的背景与当前和未来的技术相关。