Development of Smart Nanotribological Surfaces using Multifunctionalized Mesoporous Nanosphere Films

使用多功能介孔纳米球薄膜开发智能纳米摩擦表面

• 批准号: 0409625
• 负责人: Sriram Sundararajan
• 金额: $ 15.6万
• 依托单位: Iowa State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-08-01 至 2007-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0409625&HistoricalAwards=false
• 关键词: Development; Smart; Nanotribological; Surfaces; using

Development of Smart Nanotribological Surfaces using Multifunctionalized MesoporousNanosphere FilmsWith the current development of technology, a stricter requirement for controlling tribological phenomena (friction, wear and lubrication) at desired levels is arising in various engineering practices, especially in micro/nanoscale systems. Traditional tribological systems exhibit two weaknesses - the inability to adapt to changes in operating conditions to provide uniform tribological response and the durability of the tribological interface. Designing 'smart' films that exhibit self-adapting behavior to changes in operating conditions 'self-repairing' or 'self-healing' behavior would be extremely beneficial. Mesoporous Nanosphere Materials (MNMs) are a novel class of materials that exhibit a high degree of molecular design control of its internal pores and external surfaces, which can be taken advantage of to realize tribological films that are adaptive and self-healing.The research objectives of this proposal are to design novel tribological coatings/film systems utilizing mesoporous silica/alumina nanosphere materials that (i) can provide superior tribological performance formicro/nanoscale applications; (ii) are self-adapting ('smart') to changes in operating conditions and (iii) are self-healing to provide enhanced durability and longevity in tribological performance. Each phase involves chemical synthesis, deposition and chemical, structural, mechanical and tribological evaluation of each material system. The first phase of the proposed research program involves the synthesis and deposition of a closely packed monolayer of MNMs that are rigidly linked to the substrate. The second phase involves designing self-adaptive films using (a) MNMs that are internally functionalized using grafted monolayers incorporating a thermosensitive polymer (Poly-(N-isopropylacrylamide) (PNIPAAm)) which will cause a change in the frictional response of the surface below and above the lower critical solution temperature (LCST) of the polymer; (b) a self-lubricating hybrid self-assembled monolayer-nanoparticle surface utilizing MoS2 and graphitized carbon nanoparticles. The nanoparticles, being self-lubricating in nature at low and high humidity respectively, will aid in maintaining a uniform friction response of the surface. The third phase involves the design of a 'self-healing' tribological surface incorporating self-assembled monolayers (SAMs) and MNMs - a SAM covered surface with pockets of MNMs will be fabricated using photolithography and SAM chemistry. The MNMs will be externally functionalized with a polymer layer with tribological characteristics similar to that of the surface SAMs while internal pores will house free SAM molecules in solution. Wear or surface fracture initiated release of SAM molecules will allow active adsorption of molecules onto worn sites thus performing a 'self-healing' action. Micro/nanoscale tribological characterization will be performed using atomic force microscopy and microtribometry techniques developed at the PI's laboratory while synthesis of MNM films will be performed via techniques established by the co-PI.The intellectual merits of the interdisciplinary research efforts include the development of novel and innovative design strategies to produce 'smart' tribological surfaces and obtaining a better understanding of chemical and physical phenomena associated with molecular design of materials and tribological behavior. The realization of such 'smart' systems would be extremely rewarding for tribological pairs subjected to multiple and repeated environmental changes and which require very high durability, which can occur in consumer, defense, aerospace and medical applications. In addition, the research demonstrates molecular design strategies that provide ways to obtain a high degree of control in tailoring the structure and behavior of the final system. Two Ph.D. students will work on the project. They will be exposed to cross-disciplinary research and benefit from the learning experience. In order to enhance the participation of women and minority students in graduate education and research, students from these underrepresented groups will be targeted for work on the project. Research results will be disseminated into several undergraduate and graduate courses being taught by the PIs in Mechanical Engineering and Chemistry that will enhance the education of about 200 students every year. The broad impacts of the proposed activities are (i) the research activities promote interdisciplinary research efforts in system design that can lead to novel engineering strategies for superior tribological interfaces in a wide range of applications (ii) they promote increased participation of women and/or minority students through targeted recruitment efforts and (iii) the research activities enhance the education of undergraduate and graduate students of two departments at Iowa State University by emphasizing the importance of interdisciplinary research and nanoscale design strategies.

利用多功能化介孔纳米球膜开发智能纳米摩擦表面随着当前技术的发展，在各种工程实践中，特别是在微/纳米系统中，对将摩擦学现象（摩擦、磨损和润滑）控制在期望水平的要求越来越严格。传统的摩擦学系统表现出两个弱点-不能适应操作条件的变化以提供均匀的摩擦学响应和摩擦学界面的耐久性。设计出对操作条件的变化表现出自适应行为的“智能”膜，即“自我修复”或“自我修复”行为，将是非常有益的。 介孔纳米球材料（MNM）是一类新型材料，其表现出对其内孔和外表面的高度分子设计控制，本论文的研究目标是利用介孔二氧化硅/氧化铝纳米球材料设计新型摩擦学涂层/膜体系，可以为微/纳米级应用提供上级摩擦学性能;（ii）对操作条件的变化是自适应的（“智能的”）和（iii）是自修复的以提供增强的摩擦学性能的耐久性和寿命。 每个阶段涉及化学合成，沉积和化学，结构，机械和摩擦学评估的每种材料系统。拟议的研究计划的第一阶段涉及的合成和沉积的MNM紧密堆积的单层刚性连接到基板。第二阶段涉及使用（a）MNM设计自适应膜，所述MNM使用并入热敏聚合物的接枝单层进行内部官能化（聚-（N-异丙基丙烯酰胺）（PNIPAAm）），其将在低于和高于聚合物的下临界溶解温度（LCST）时引起表面摩擦响应的变化;（B）利用MoS 2和石墨化碳纳米颗粒的自润滑混合自组装单层-纳米颗粒表面。纳米颗粒在低湿度和高湿度下分别具有自润滑性质，将有助于保持表面的均匀摩擦响应。第三阶段涉及的“自我修复”的摩擦学表面的设计，结合自组装单分子层（SAM）和MNM-SAM覆盖的表面与口袋的MNM将使用光刻和SAM化学制造。MNM将用具有与表面SAM类似的摩擦学特性的聚合物层进行外部官能化，而内部孔将容纳溶液中的游离SAM分子。磨损或表面断裂引发的SAM分子释放将允许分子主动吸附到磨损部位上，从而执行“自我修复”作用。微/纳米级摩擦学表征将使用PI实验室开发的原子力显微镜和微摩擦学技术进行，而MNM膜的合成将通过共同建立的技术进行。跨学科研究工作的智力价值包括开发新颖和创新的设计策略，以生产“智能”摩擦表面，并更好地了解化学和物理与材料的分子设计和摩擦学行为相关的现象。这种“智能”系统的实现对于经受多次和重复环境变化并且需要非常高的耐久性的摩擦学对来说将是非常有益的，这可能发生在消费者、国防、航空航天和医疗应用中。此外，该研究还展示了分子设计策略，这些策略提供了在定制最终系统的结构和行为时获得高度控制的方法。 两个博士学生们将在这个项目上工作。他们将接触到跨学科的研究，并从学习经验中受益。为了加强妇女和少数民族学生对研究生教育和研究的参与，该项目的工作将针对这些代表性不足群体的学生。研究成果将传播到几个本科生和研究生课程正在教授的PI在机械工程和化学，这将提高约200名学生的教育，每年。拟议活动的广泛影响是：（i）研究活动促进系统设计中的跨学科研究工作，从而在广泛的应用中为上级摩擦学界面带来新的工程战略;（ii）通过有针对性的招聘工作，促进妇女和/或少数民族学生更多地参与;以及（iii）这些研究活动通过强调跨学科研究和纳米级设计策略的重要性，加强了爱荷华州州立大学两个系的本科生和研究生的教育。