Use Particle-Tracking Velocimetric Observations to Guide Evidence-Based Investigations of PolymerDynamics in Presence of Chain Entanglement

使用粒子跟踪测速观测来指导存在链缠结的聚合物动力学的循证研究

• 批准号: 0804726
• 负责人: Shi-Qing Wang
• 金额: $ 34.2万
• 依托单位: University of Akron
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-05-01 至 2012-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0804726&HistoricalAwards=false
• 关键词: Use; Particle; Tracking; Velocimetric; Observations

TECHNICAL SUMMARYThe proposed research aims to achieve three objectives: (A) carefully examining the previous results to identify potential sources of technical error and scientific ambiguity; (B) removing experimental difficulties to verify whether the new emerging picture would still hold in absence of any artifacts that have caused controversies in the literature; (C) building on the newly available understanding to further probe the nature of disintegration of chain entanglement network due to external deformation. Specifically, many current findings have not been proved to beyond doubt and cannot form the new phenomenological foundation for polymer rheology unless improved experiments are carried out. These experiments include (i) interrogation of strain-induced chain disentanglement under circumstances where the sample at the edge of a shear cell would not suffer fracture and (ii) flow birefringence measurements in absence of any inclusions such as solid particles that have been suspected by de Gennes to be the source of shear banding. Single-molecule imaging velocimetry is proposed as an effective method to probe velocity field in entangled systems without any foreign particles and to directly determine whether shear inhomogeneity would arise from flow-induced polymer migration or from non-uniform chain disentanglement. Finally, in anticipation of potential implications for polymer processing, particle-tracking velocimetric technique will be applied to examine effect of chain disentanglement in pressure-driven flow and related phenomena.NON-TECHNICAL SUMMARY:Each year, more than two hundred billion pounds of plastic and rubber materials are made into consumer products in this country. Such a huge volume typically flows in a manner similar to pouring honey or squeezing tooth paste. How the various polymeric materials flow under different processing conditions is a subject of both academic and economic importance. The fruits of the proposed studies could alter our long-held knowledge about polymer flow and transform the contents of existing textbooks on the subject. Current scientific findings and proposed research offer new hope that could eventually give the domestic market a cutting edge in the global competition and innovation for more efficient production of petroleum-based consumer goods of higher quality. Ultimately, the outcome of the proposed work could directly impact the R&D directions in the plastic and rubber industries. The impact of this investigation is clearly going beyond the border of the United State, as the emerging new picture begins to be discussed in classroom and recorded for video streaming on the world wide web at http://eres.avs.uakron.edu/eres/coursepass.aspx?cid=647. The visualization-intensive nature of the research also makes it attractive materials for youngsters in middle and high schools, making science intuitive, observational and straightforward to perceive.

本研究的目的有三：（A）仔细检查以前的结果，以确定技术错误和科学模糊性的潜在来源;（B）消除实验困难，以验证新出现的图像是否仍然成立，如果没有任何人工制品，在文献中引起争议;（C）在现有新认识的基础上，进一步探讨由于外部变形而导致的链缠结网络解体的本质。 具体地说，目前的许多发现还没有被证明是毫无疑问的，不能形成新的唯象基础，除非进行改进的实验。 这些实验包括（i）在剪切单元边缘处的样品不会发生断裂的情况下询问应变诱导的链解缠结，以及（ii）在不存在任何夹杂物（例如de Gennes怀疑是剪切带来源的固体颗粒）的情况下测量流动双折射。 单分子成像测速技术被认为是一种有效的方法，可以探测没有任何外来粒子的纠缠系统中的速度场，并直接确定剪切不均匀性是否会产生流动诱导的聚合物迁移或从非均匀链解缠结。 最后，在聚合物加工的潜在影响的预期中，粒子跟踪测速技术将被应用于研究在压力驱动的流动和相关的phenomenon.Non-Technical摘要：每年，超过两千亿磅的塑料和橡胶材料被制成消费品在这个国家。 如此巨大的体积通常以类似于倾倒蜂蜜或挤压牙膏的方式流动。 各种聚合物材料在不同加工条件下如何流动是一个具有学术和经济意义的课题。 这些研究成果可能会改变我们长期以来对聚合物流动的认识，并改变现有教科书的内容。 目前的科学发现和拟议的研究提供了新的希望，最终可能使国内市场在全球竞争和创新中处于领先地位，以更有效地生产更高质量的石油消费品。 最终，拟议工作的结果可能直接影响塑料和橡胶行业的研发方向。 这项调查的影响显然超出了美国的边界，因为新出现的新图片开始在课堂上讨论，并在万维网上录制视频流，网址为http://eres.avs.uakron.edu/eres/coursepass.aspx?。cid=647。 研究的可视化密集型性质也使其成为初中和高中青少年的有吸引力的材料，使科学直观，观察和直接感知。