Understanding the Mechanism of Simultaneous Oleophobic/Hydrophilic Behavior: When a Nanometer-Thick Polymer Coating meets a Solid Surface

这项资助的研究目的是阐明在涂有纳米厚聚合物的固体表面上观察到的同时疏油/亲水行为的基本机制。尽管对水的可湿性比对油的可湿性更强的表面有许多重要的应用，但这种表面很少被报道。最近的研究表明，这种异常润湿行为可以通过在固体基底上涂上纳米厚的聚合物涂层来实现。然而，导致这一有趣而令人困惑的结果的机制至今仍不清楚。为了了解其机理，PI将通过x射线反射（XRR）和飞行时间二次离子质谱（ToF-SIMS）研究聚合物-基质相互作用如何准确影响聚合物纳米膜中的“静态”和“动态”孔，以建立水和油润湿过程的动力学。PI还将确定关键参数，包括聚合物结构、衬底结构和光化学辐照过程，这些参数决定了同时的疏油/亲水性。如果成功，将发现同时疏油/亲水性的潜在机制，并建立设计标准。同时的疏油/亲水表面在许多重要应用中是非常理想的，包括无洗涤剂清洁，防雾和油水分离。了解如何制造这样的表面将对环境和能源领域产生重大影响。该研究项目还将促进来自科学和工程领域代表性不足群体的学生的参与，包括为研究生和本科生提供研究培训，开发新课程，开展外展活动，例如最近在PI的指导下在匹兹堡大学建立的ENGAGE项目。通过多方面的活动，PI将促进各年龄段学生对科学和工程学科的兴趣和参与。

The research objective of this grant is to elucidate the fundamental mechanism that is responsible for simultaneous oleophobic/hydrophilic behavior observed on the solid surface coated with a nanometer-thick polymer. Although surfaces more wettable to water than to oil have many important applications, such surfaces have been very rarely reported. Recent studies indicate that such anomalous wetting behavior could be achieved by applying some nanometer-thick polymer coating on some solid substrate. However, the mechanism responsible for the interesting and puzzling result remains unclear to date. To understand the mechanism, the PI will investigate how exactly the polymer-substrate interaction affects the "static" and "dynamic" holes in the polymer nanofilms by x-ray reflectometry (XRR) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) to establish the kinetics of the wetting process of water and oil. The PI also will identify the key parameters, including polymer structure, substrate structure, and photochemical irradiation process, that govern simultaneous oleophobicity/hydrophilicity.If successful, the underlying mechanism of simultaneous oleophobicity/hydrophilicity will be discovered, and design criteria will be established. Simultaneous oleophobic/hydrophilic surfaces are highly desirable in many important applications, including detergent-free cleaning, anti-fogging, and oil-water separating. Understanding how to fabricate such surfaces will greatly impact the field of environment and energy. The research project also will promote the participation of the students from underrepresented groups in science and engineering fields, including providing research training to graduate and undergraduate students, developing a new courses, and conducting outreach activities, such as the ENGAGE program that recently was established at the University of Pittsburgh under the PI's direction. Through multi-faceted activities, the PI will promote interest and participation in science and engineering disciplines on the part of students of all ages.