Understanding Acid-Base Interactions using Interface-Sensitive Spectroscopy

使用界面敏感光谱了解酸碱相互作用

• 批准号: 1105370
• 负责人: Ali Dhinojwala
• 金额: $ 50万
• 依托单位: University of Akron
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-06-01 至 2016-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1105370&HistoricalAwards=false
• 关键词: Understanding; Acid; Base; Interactions; using

TECHNICAL SUMMARYThe objective of this NSF project is to exploit the interface sensitivity of infrared-visible sum frequency generation spectroscopy (SFG) to measure acid-base interactions at solid-solid interfaces. An understanding of polar interactions is important in the areas of adhesion, friction, and wetting. In-situ characterization of acid-base interactions and their role in adhesion of these coatings at the molecular level and under kinetic conditions (for example: during sliding and mechanical contact) pose a formidable challenge to scientists. The principal investigator (PI), Professor Dhinojwala, proposes to directly probe the acid-base interactions for polymers in contact with inorganic sapphire substrate or sapphire modified with self-assembled monolayers with acidic or basic end groups to understand these interactions at the molecular level. SFG instrumentation is used to directly monitor the shifts in the vibrational peaks of the acidic and basic groups and correlate them with interaction energies to study exchange kinetics at polymer-solid interface as a function of time, temperature, and composition. This proposal explores the kinetics and thermodynamics of surface segregation driven by acid-base interactions. In addition, this proposal focuses on blends and copolymers to study the role of these interaction energies on the segregation of near solid-solid interfaces and dynamics during sliding and peel-off. The study of interaction energies and its experimental results have important implications in understanding friction and adhesion hysteresis. These interaction energies will be compared with adhesion measurements using the Johnson-Kendall- Roberts (JKR) geometry. In addition to these experiments, the PI will also conduct atomistic molecular dynamics simulations (MD) and quantum calculations to understand the magnitude of the frequency shift and its effect on segregation. The SFG, MD, and quantum calculations of these experiments will be used in conjunction to understand the influence of surface concentration, steric constraints, and surface roughness on acid-base interactions and the consequences on adhesion energies. NON-TECHNICAL SUMMARYThe fundamental understanding of acid-base interactions helps in predicting the adhesion of polymers to substrates and in developing the next generation of enhanced coatings and adhesives for applications in multiple areas, including, but not limited to, electronics, bio-mineralization, peptide-based surface recognition, nano-composites and solar cells. This project will support two graduate students who will work together as a group with experts in the areas of surface science, MD simulations, and industrial research. The students working with this broad multidisciplinary group will be provided training to work as a team. Additionally, the graduate students will also have the opportunity to supervise NSF-REU students during the summer. As a volunteer Director of District 5 Science Day, the PI will continue his outreach to host District Science Day at The University of Akron (UA). The PI has also initiated a mentorship program where he brings together scientists from industries and academia to mentor the science projects. This mentorship program was started in the city of Hudson, Ohio, and the PI plans to make this program available to all schools in District 5. In collaboration with UA's business school and Austen Bio-innovation Institute in Akron, the PI is helpping in developing a multidisciplinary Bio-design class offered to UA students in physical sciences, business, and medicine with a goal of observation or experimental based approach to solve problems. This class will be taught in collaboration with professors from UA's business and medicine schools.

技术总结该NSF项目的目的是利用红外可见总和频率产生光谱（SFG）的界面灵敏度来测量固相接口处的酸碱相互作用。 对极性相互作用的理解在粘附，摩擦和润湿领域很重要。 酸碱相互作用的原位表征及其在分子水平和动力学条件下（例如：在滑动和机械接触期间）在这些涂层粘附中的作用构成了对科学家的巨大挑战。 首席研究员（PI），Dhinojwala教授提议直接探测与与无机蓝宝石底物接触的聚合物的酸碱相互作用，或者用具有酸性或基本最终基团的自组装单层修饰的无机蓝宝石底物或蓝宝石在分子水平上了解这些相互作用。 SFG仪器用于直接监测酸性和基本组振动峰的变化，并将它们与相互作用能量相关联，以研究在聚合物 - 固体界面处的交换动力学，这是时间，温度和组成的函数。该建议探讨了由酸碱相互作用驱动的表面隔离的动力学和热力学。此外，该建议集中于研究这些相互作用能在滑动和剥落过程中近乎固体界面和动力学的隔离方面的作用。相互作用能量及其实验结果的研究对理解摩擦和粘附滞后具有重要意义。这些相互作用的能量将与使用Johnson-Kendall-Roberts（JKR）几何形状进行比较。除这些实验外，PI还将进行原子分子动力学模拟（MD）和量子计算，以了解频移的大小及其对分离的影响。 这些实验的SFG，MD和量子计算将结合使用，以了解表面浓度，空间约束和表面粗糙度对酸碱相互作用的影响以及对粘附能的影响。非技术总结，对酸碱相互作用的基本了解有助于预测聚合物对底物的粘附以及开发下一代增强的涂料和粘合剂，以在多个领域的应用中进行应用，包括但不限于电子，生物矿化，肽表面识别，Nano-Composites，Nano-Composites和solar Cell和solar Cell和solar Cell。 该项目将支持两名研究生，他们将与表面科学，MD模拟和工业研究领域的专家一起共同合作。与这个广泛的多学科小组一起工作的学生将接受团队合作的培训。此外，研究生还将有机会在夏季监督NSF-REU学生。 作为第5区科学日的志愿主任，PI将继续他在阿克伦大学（UA）举办地区科学日的宣传。 PI还启动了一项指导计划，他将来自行业和学术界的科学家汇集在一起​​，以指导科学项目。该指导计划始于俄亥俄州的哈德逊市，PI计划将该计划提供给第5区的所有学校。与Akron的UA商学院和Austen Bio Innecation Institute合作，PI正在为基于物理学的学生提供多学科Bio-Design的方法，以实现型和医学，以实现型和医学，或者与Medicess和Medicial一起开发多学科的生物识别课程，或者进行实验。该课程将与UA商业和医学学校的教授合作教授。