Characterization of Heat Transport Properties of Polymers for Nanoscale Thermal Processing

低成本、高通量的纳米制造技术对于确保现代工程的各个领域，特别是信息处理、存储和通信技术的持续发展至关重要。许多新兴的纳米制造技术要求对薄(100 Nm)聚合物薄膜进行精确的热加工。例如，纳米压印技术使用包含纳米级浮雕图案的刚性模板，使加热到玻璃化转变温度以上的聚合物层机械变形。得到的图案化聚合物用作后续纳米制造工艺的掩蔽层。局部加热也可以用来选择性地将嵌入纳米粒子的聚合物交联，以产生微米和纳米级的特征。受控加热起着重要的作用，因为聚合物薄膜中发生的物理或化学过程的动力学是温度的敏感函数。基于物理的聚合物加工设计和优化要求对热传输有基本的了解。在纳米尺度上，基础研究的需求尤其迫切，因为纳米限制和其他表面/界面效应预计将强烈影响聚合物的行为。这项研究开发了微型制造的实验平台，用于研究经历物理或化学转变(如玻璃化转变和聚合)的纳米级聚合物薄膜中的热输运。聚合物薄膜的热传输特性和局部瞬时加热过程中物理化学转变的空间范围将作为温度和升温速率的函数来确定。所建议的研究具有高度跨学科的性质，涉及到大分子体系中的热传递的基本方面。这项拟议研究的实验数据将为了解具有重大科学意义的纳米级聚合物动力学提供有用的见解。通过拟议的调查获得的基本认识还将使系统地探索新的热加工方案以及优化现有的聚合物纳米级热加工方法。这项研究还提供了一个令人兴奋的机会来培训研究生和高级本科生，并帮助他们获得跨学科的技能。学生将有一个非常有益的经验，他们的贡献可能会产生直接影响的项目具有很大的实际意义和公众认可度。拟议研究的这些方面将特别有助于激励本科生追求工程/科学事业。该奖项由化学和运输系统部门的热运输和热处理项目支持。

AbstractLow-cost high-throughput nano-manufacturing techniques are critical in ensuring continued progress in diverse areas of modern engineering, especially the information processing, storage, and communication technologies. Many emerging nano-manufacturing techniques require precise thermal processing of thin ( 100 nm) polymer films. The nano-imprint technique, for example, mechanically deforms polymer layers heated above glass transition temperature using a rigid template that contains nano-scale relief patterns. The resulting patterned polymer serves as a masking layer for subsequent nano-fabrication processes. Localized heating can also be used to selectively cross-link polymers embedded with nano-particles to produce micro- and nano-scale features. Controlled heating plays an important role because kinetics of physical or chemical processes occurring in polymer films is a sensitive function of temperature.Physics-based design and optimization of polymer processing requires fundamental understanding of thermal transport. The need for fundamental studies is particularly acute at nanoscales because nano-confinement and other surface/interface effects are expected to strongly influence the behavior of polymers. The proposed research develops micro-fabricated experimental platforms to investigate thermal transport in nanoscale polymer films undergoing physical or chemical transformation, such as glass transition and polymerization. The thermal transport properties of polymer films and spatial extent of physico-chemical transformation during localized transient heating will be determined as a function of temperature and heating rate.The proposed research is highly interdisciplinary in nature and addresses fundamental aspects of heat transfer in macromolecular systems. Experimental data from the proposed research will provide useful insight into nanoscale polymer dynamics that is of great scientific interest. Fundamental understanding gained through the proposed investigation will also enable systematic exploration of novel thermal processing schemes as well as optimization of existing nanoscale thermal processing methods for polymers.The research also offers an exciting opportunity to train graduate and advanced undergraduate students and help them acquire interdisciplinary skill sets. Students will have a very rewarding experience of working on projects of great practical relevance and public recognition where their contribution can potentially make direct impact. These aspects of the proposed research will be particularly helpful in motivating undergraduate students to pursue engineering/scientific career.This award is being supported by the Thermal Transport and Thermal Processing Program of the Chemical and Transport Systems Division.