CAREER: Creasing of Surface-Attached Polymer Gels

本研究计划的目标是详细了解表面附着聚合物凝胶溶胀引起的折痕不稳定性。 虽然这种现象至少从19世纪中期以来就在各种背景下被观察到，但它仍然没有得到很好的描述，也没有得到广泛的重视。 然而，它对生物材料和“智能”表面等领域的现代材料研究具有重要意义，并为具有可切换特性的表面设计提供了独特的机会。 PI的工作将集中在模型水凝胶系统，允许定量测定以下内容：（i）折痕发生的条件以及不稳定性的发生如何取决于软表面的材料特性;（ii）折痕自然采用的结构，以及如何通过适当的材料设计控制这些结构;以及（iii）折痕形成如何改变表面特性。 利用通过这些实验获得的基本理解，将设计出响应环境线索动态改变其地形和化学的响应表面。 这项研究将被整合到研究生、本科生和K-12水平的学生的实验室和课堂上的各种教育体验中。非技术总结用聚合物薄层涂覆材料提供了一种控制其表面性能的强大方法。 例如，表面附着的水凝胶（主要由水组成的软聚合物固体）用于调节材料与生物细胞的相互作用，并创造出能够感知和响应环境变化的“智能”材料。 在某些条件下，这些软聚合物层可以经历不稳定性，其中它们的自由表面自发地弯曲和折叠以形成形貌特征。 该项目旨在深入了解这种不稳定性及其对表面特性的重要性，并对生物界面材料的设计方式以及可以根据需要改变其特性的表面的创建产生重大影响。 除了为材料研究跨学科领域的本科生和研究生提供技术培训外，该计划还将为麻省大学的下一代科学教育工作者提供一个扎实介绍有效教学策略的机会。 通过与波士顿科学博物馆的合作，该计划的科学成果将被纳入到大学以外的更广泛受众的模块中。

TECHNICAL SUMMARYThis goal of this research program is to develop a detailed understanding of the creasing instability induced by swelling of surface-attached polymer gels. Though this phenomenon has been observed in a variety of contexts since at least the mid-1800's, it remains poorly characterized and not widely appreciated. However, it has important implications for modern materials research in areas such as biomaterials and "smart" surfaces, and offers unique opportunities for the design of surfaces with switchable properties. The PI's work will focus on model hydrogel systems that allow quantitative determination of the following: (i) the conditions under which creasing occurs and how the onset of the instability depends on the material properties of the soft surface; (ii) the structures naturally adopted by creases, and how these structures can be controlled by proper material design; and (iii) how surface properties are altered by crease formation. Using the fundamental understanding gained through these experiments, responsive surfaces that dynamically alter their topography and chemistry in response to environmental cues will be designed. This research will be integrated into a variety of educational experiences in the laboratory and the classroom for students at the graduate, undergraduate, and K-12 levels.NON-TECHNICAL SUMMARYCoating a material with a thin layer of polymers provides a powerful way to control its surface properties. For example, surface-attached hydrogels (soft polymeric solids consisting primarily of water) are used to tune the interactions of materials with biological cells, and to create "smart" materials that sense and respond to changes in their environment. Under certain conditions, these soft polymer layers can undergo an instability in which their free surfaces spontaneously buckle and fold to form topographical features. This project aims to develop a thorough understanding of this instability, and its importance for surface properties, with significant impacts expected on the way that materials at the biological interface are designed, and on the creation of surfaces that can alter their properties on demand. In addition to providing technical training for undergraduate and graduate students in interdisciplinary areas of materials research, this program will offer the next generation of science educators at UMass an opportunity for a solid introduction to effective teaching strategies. Through a partnership with the Boston Museum of Science, the scientific results from this program will be incorporated into modules that reach a broader audience beyond the university.