Viscous Fluid Dynamics and Characterization of Nano-Structured Polymers

纳米结构聚合物的粘性流体动力学和表征

• 批准号: 0071743
• 负责人: Harald Ade
• 金额: $ 31.25万
• 依托单位: North Carolina State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-05-01 至 2003-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0071743&HistoricalAwards=false
• 关键词: Viscous; Fluid; Dynamics; Characterization; Nano

Theoretical work over the last years has shown that the dynamics of two-dimensional viscous fluids is a richer phenomenon than hitherto believed and described theoretically. Depending on the hydrodynamic and diffusive time scales, the scaling invariance of phase coarsening can break down and jagged domains can form. In preliminary experiments, the various viscosity regimes considered in the theoretical simulations have been experimentally observed. A detailed quantitative comparison to theory will be made and the phase separation of viscous fluids, such as polymer melts, will be experimentally determined for fluid pairs ranging from highly immiscible to weakly incompatible. The primary model systems will be poly(methylmethacrylate)/polystyrene (PS), PS/brominated PS, and PS/poly(vinyl methyl ether) above their glass transition temperature. It is expected that data is acquired outside the applicability of the present simulations, most notably fluids with asymmetric composition and volume fractions as well as asymmetric viscosities. An interesting extension to binary viscous liquids will be the investigation of systems that contain small particles or beads in one of the phases. Recent theory shows that the addition of hard particles significantly changes both the kinetics and the morphology of the phase separation. In order to generate truly two-dimensional fluids, a special sample preparation method that will sandwich the polymer films between Si3N4 membranes will be developed. The surfaces will be treated to make them neutral or near neutral for the polymers utilized. In the process, control over confinement effects such as changes of viscosity in thin polymer films will be achieved. Near Edge X-ray Absorption Fine Structure (NEXAFS) microscopy will be an important characterization tool, complemented by other microscopies (AMF, VLM, SEM). - Improvements in the theoretical understanding of NEXAFS spectra will be pursued. The accuracy of compositional quantitation will be improved.Students will be trained in executing interdisciplinary research projects situated at the interface of Physics, Chemistry, Materials and Polymer Science. Fundamental understanding of polymer thin films will be advanced, which might improve applications such as coating, adhesives, lubricants, inks and a variety of thin films applications in the semiconductor industry. Part of the effort continues a longstanding collaboration with Dow Chemical.

过去几年的理论工作表明，二维粘性流体的动力学比迄今为止相信并从理论上描述的更丰富的现象。 根据流体动力学和扩散时间尺度，相结实的缩放不变性可能会分解，并且锯齿状的域可能会形成。 在初步实验中，已经观察到了理论模拟中考虑的各种粘度状态。 将与理论进行详细的定量比较，并将通过实验确定粘性流体的相位分离，例如聚合物熔体，用于从高度不混溶到弱不相容的流体对。 主要模型系统将是聚（甲基丙烯酸酯）/聚苯乙烯（PS），PS/溴化的PS，PS/聚（乙烯基甲基醚）在其玻璃过渡温度上方。 预计数据是在本模拟的适用性之外获得的，最著名的是具有不对称组成和体积分数以及不对称粘度的流体。 对二元粘性液体的一个有趣的扩展是研究其中一个阶段中包含小颗粒或珠子的系统。 最近的理论表明，硬粒子的添加显着改变了相位分离的动力学和形态。 为了产生真正的二维流体，将开发一种特殊的样品制备方法，将SI3N4膜之间的聚合物膜夹在三明治中。 将对表面进行处理，以使其用于使用的聚合物中性或接近中性。 在此过程中，将控制对限制效应的控制，例如薄聚合物膜中粘度的变化。 近边缘X射线吸收细胞（NEXAFS）显微镜将是一个重要的特征工具，由其他显微镜（AMF，VLM，SEM）互补。 - 将追求对Nexafs光谱的理论理解的改进。 构图定量的准确性将提高。学生将在执行位于物理，化学，材料和聚合物科学界面的跨学科研究项目中进行培训。 对聚合物薄膜的基本理解将是先进的，这可能会改善涂层，粘合剂，润滑剂，墨水和各种薄膜在半导体行业中的应用。 部分努力继续与Dow Chemical进行了长期合作。