Viscoelastic Response of Ultrathin Polymer Films: Bubble Inflation, Liquid Dewetting and Molecular Architecture Effects

超薄聚合物薄膜的粘弹性响应：气泡膨胀、液体反润湿和分子结构效应

• 批准号: 1207070
• 负责人: Gregory McKenna
• 金额: $ 37.5万
• 依托单位: Texas Tech University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-05-01 至 2016-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1207070&HistoricalAwards=false
• 关键词: Viscoelastic; Response; Ultrathin; Polymer; Films

TECHNICAL SUMMARY: The work is a fundamental investigation of the viscoelastic response of ultrathin polymer films in two different conditions. The work will compare, contrast, and seek origins of differences between the nanobubble inflation method developed by the PI at Texas Tech University and the liquid dewetting method developed by Bodiguel and Fretigny in Paris (which are the only methods currently available to measure the viscoelastic response of unsupported films). The two techniques had shown substantial differences in glass transition temperatures as functions of film thickness. The two methods differ in that one measures films with free surfaces and the other measures films floating on a mobile substrate. The planned research will examine the effects of changing substrate, molecular weight, and molecular architecture on the viscoelastic properties of ultrathin polymer films. It will explore the hypothesis that the relevant differences in confinement behavior are related to very subtle differences in surface energy/surface interactions and will provide new data focused on the understanding of how surfaces and interfaces impact the dynamics of polymers confined to the nanometer size scale.NON-TECHNICAL SUMMARY: The dramatic influence of nanoscale confinement on material behavior is exemplified by the response of ultrathin polymer films that show tremendous property changes, for example, in freely suspended films having nanometer thicknesses. Yet the origins of these changes are not yet elucidated. The present work probes these changes using two novel nanomechanical test methods. The work compares and contrasts mechanical properties of a series of polymers having different molecular characteristics. In addition, because there is such a strong apparent effect of the environment seen by the film surface, the work probes the behavior of the ultrathin polymer films exposed to liquids having different properties. The research provides new data in the understanding of how surfaces and interfaces impact the mechanics of polymers confined to the nanometer size scale. The project also has an important component that trains graduate students and, in addition to their scientific training, involves them in a STEM outreach program to young girls through the "Science: It's a Girl Thing" Program at Texas Tech University.

技术摘要：这项工作是对两种不同条件下超薄聚合物膜的粘弹性响应的基本研究。这项工作将比较，对比和寻求起源的起源，这是PI在德州理工大学开发的纳米泡通货膨胀方法与巴黎Bodiguel和Fretigny开发的液体脱水方法（这是目前可用于衡量粘弹性响应的唯一方法）不受支持的电影）。 这两种技术显示玻璃过渡温度作为膜厚度的功能存在实质性差异。 这两种方法的不同之处在于，一种方法是用自由表面的胶片和其他措施浮在移动基板上的膜。计划的研究将研究不断变化的底物，分子量和分子结构对超薄聚合物膜粘弹性特性的影响。它将探讨以下假设：限制行为的相关差异与表面能量/表面相互作用的非常细微的差异有关，并将提供新的数据，重点是理解表面和界面如何影响局限于纳米尺寸尺寸量表的聚合物的动态。非技术摘要：超薄聚合物膜的响应体现出巨大的特性变化，例如，在具有纳米厚度的自由悬浮膜中，纳米级限制对物质行为的戏剧性影响。 然而，这些变化的起源尚未阐明。 目前的工作使用两种新型的纳米力学测试方法探究了这些变化。 这项工作比较和对比具有不同分子特征的一系列聚合物的机械性能。此外，由于膜表面看到的环境具有如此强大的明显影响，因此该作品探测了暴露于具有不同特性的液体的超薄聚合物膜的行为。该研究提供了新数据，以理解表面和界面如何影响局限于纳米尺寸尺度的聚合物的力学。 该项目还具有一个重要的组成部分，可以通过Texas Tech University的“ Science：这是女孩：这是女孩事物”计划向年轻女孩参加STEM外展计划的培训。