Collaborative Research: Line-Active Amphiphiles for Nanostructure Stability

合作研究：用于纳米结构稳定性的线活性两亲物

• 批准号: 0906727
• 负责人: T. Randall Lee
• 金额: $ 38.9万
• 依托单位: University of Houston
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2013-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0906727&HistoricalAwards=false
• 关键词: Collaborative; Research; Line; Active; Amphiphiles

TECHNICAL SUMMARYThe proposed research will develop a fundamental understanding of how line-active molecules (called linactants in the proposal) can be used to modify the line tension of nano- and meso-scale features within molecular monolayers. The ability to control line tension will be necessary to stabilize objects created using next-generation nanolithographic methods; furthermore, development and use of linactants will permit the creation of self-organized 2D features that are analogous to 3D micelles or microemulsions. The proposed experimental strategy will rely on molecular aggregation within two- and three-component monomolecular films prepared by Langmuir-Blodgett (LB) deposition and related self-assembly methods. Key components include the rational design and synthesis of line-active molecules that play roles in two-dimensions (2D) that are analogous to those of amphiphilic surfactant molecules in three-dimensional (3D) micelles, bilayers, and microemulsions. In the same manner in which a 3D surfactant possesses hydrophobic and hydrophilic regions, these linactant molecules will possess two dissimilar hydrophobic molecular moieties (either distinct tails or blocks within a single tail); each moiety is designed to interact favorably with one of the respective components of a phase-separated two-component monolayer film. Previous work by this collaborative team focused on linactants having one hydrocarbon tail or block and one fluorinated tail or block. These compounds successfully reduced the line tension between hydrocarbon- and fluorocarbon-rich monolayer phases; distinctive 2D self-assembly of the linactants into nanometer-scale clusters analogous to micelles was also observed. The specific objectives of this project are (1) to obtain a clearer understanding of the molecular mechanisms leading to linactant behavior in fluorocarbon/hydrocarbon mixed monolayer systems, and (2) to generalize the linactant phenomenon beyond fluorocarbon/hydrocarbon systems by designing and synthesizing linactants for use in alternative binary monolayer mixtures, including hydrocarbon/silicone, saturated/unsaturated hydrocarbons, and cholesterol/lipid.NON-TECHNICAL SUMMARYThe fundamental scientific research outlined in this proposal will lead to advances in the technologically important and emerging field of nanotechnology. As devices and materials are made smaller and smaller, the influence of surfaces and interfaces becomes increasingly important. In particular, the influence of surface tension leads to instabilities that can instigate the degradation of nanoscale patterns and structural features. For this reason, the fabrication of functional nanoscale structures requires the addition of molecular stabilizers -- molecules that partition at surfaces and reduce the surface tension between edges and domain boundaries. The science behind such stabilizers is reasonably well understood for traditional three-dimensional materials, such as micelles, emulsions, and even nanoparticles. However, no such science exists for molecules that are needed to stabilize two-dimensional nanostructures (i.e., nanoscale patterns fabricated on surfaces). The stability of such surface nanopatterns is required for future applications in molecular electronics, cataysis, biosensors, and biomaterials. This collaborative research project, which encompasses two distinct disciplines at two separate universities, will seek to broaden the participation of both women and minorities in science and education. All participants will be encouraged to join their local professional societies and to attend local and national meetings to advance our dissemination efforts. Also, through their participation in a variety of educational and outreach programs (e.g., REUs, RETs, NUE, GAANN, CU-Discovery Learning Center, Materials Science from CU K-12 outreach, Colorado High School Honors Institute, Houston Louis Stokes Alliance for Minority Participation, UH Latino Outreach, and Welch Summer Scholars), the researchers will continue to share this project with students, teachers, and members of the community at large. Furthermore, the proposed effort to link fundamental scientific discovery with technological and societal impact offers an ideal platform from which to communicate the benefits of research to the public.

技术总结拟议的研究将对如何使用线活性分子(在提案中称为线性剂)来改变分子单分子层中纳米和介观特征的线张力有一个基本的理解。控制线张力的能力对于稳定使用下一代纳米光刻方法创建的对象将是必要的；此外，连接剂的开发和使用将允许创建类似于3D胶束或微乳液的自组织2D特征。所提出的实验策略将依赖于通过Langmuir-Blodgett(LB)沉积和相关的自组装方法制备的双组分单分子膜和三组分单分子膜中的分子聚集。关键组成部分包括合理设计和合成在二维(2D)中发挥作用的线活性分子，这些分子类似于在三维(3D)胶束、双层和微乳液中的两亲性表面活性剂分子。与3D表面活性剂具有疏水和亲水区域的方式相同，这些乳化剂分子将拥有两个不同的疏水分子部分(要么是不同的尾部，要么是单个尾部内的块)；每个部分都被设计成与相分离的双组分单分子膜的各个组分中的一个有利地相互作用。这个合作团队之前的工作集中在具有一个碳氢化合物尾部或嵌段和一个氟化尾部或嵌段的链段。这些化合物成功地降低了富含碳氢化合物和碳氟化合物的单层相之间的线张力；还观察到这些连接物独特的2D自组装成类似胶束的纳米级簇。这个项目的具体目标是(1)更清楚地了解导致氟碳/烃混合单层体系中直线行为的分子机制，以及(2)通过设计和合成用于替代二元单层混合物的直线现象，将直线现象推广到氟碳/烃体系，包括烃/硅、饱和/不饱和碳氢化合物和胆固醇/脂。随着器件和材料变得越来越小，表面和界面的影响变得越来越重要。特别是，表面张力的影响会导致不稳定性，这可能会引发纳米级图案和结构特征的退化。出于这个原因，功能纳米级结构的制造需要添加分子稳定剂--分子在表面进行分割，降低边缘和区域边界之间的表面张力。这类稳定剂背后的科学对于传统的三维材料，如胶束、乳液，甚至纳米颗粒，都有相当好的理解。然而，对于稳定二维纳米结构(即表面制造的纳米级图案)所需的分子，还没有这样的科学。这种表面纳米粒子的稳定性是未来在分子电子学、催化、生物传感器和生物材料中应用的必要条件。这一合作研究项目包括两所不同大学的两个不同学科，将寻求扩大妇女和少数群体在科学和教育方面的参与。将鼓励所有参与者加入他们当地的专业协会，并参加地方和国家会议，以推动我们的宣传工作。此外，通过参与各种教育和外展计划(例如，REUS、RETS、NUE、GAANN、CU-Discovery学习中心、CU K-12外展的材料科学、科罗拉多高中荣誉学院、休斯顿路易斯·斯托克斯少数民族参与联盟、密歇根州立大学拉丁裔外展和韦尔奇夏季学者)，研究人员将继续与学生、教师和广大社区成员分享这一项目。此外，拟议的将基础科学发现与技术和社会影响联系起来的努力提供了一个向公众传播研究成果的理想平台。