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是一种比迄今为止理论上所认为和描述的更丰富的现象。 根据流体动力学和扩散时间尺度，相粗化的尺度不变性可能会被破坏，并可能形成锯齿状域。 在初步实验中，通过实验观察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，并将通过实验确定从高度不混溶到弱不相容的流体对的粘性流体（例如聚合物熔体）的相分离。 主要模型系统将是高于其玻璃化转变温度的聚（甲基丙烯酸甲酯）/聚苯乙烯（PS）、PS/溴化PS和PS/聚（乙烯基甲基醚）。 预计数据是在当前模拟的适用范围之外获得的，尤其是具有不对称成分和体积分数以及不对称粘度的流体。 二元粘性液体的一个有趣的扩展将是研究其中一相包含小颗粒或珠子的系统。 最近的理论表明，硬颗粒的添加显着改变了相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，将聚合物薄膜夹在 Si3N4 膜之间。 表面将经过处理，使其对所用聚合物呈中性或接近中性。 在此过程中，将实现对限制效应的控制，例如聚合物薄膜中粘度的变化。 近边 X 射线吸收精细结构 (NEXAFS) 显微镜将成为一种重要的表征工具，并得到其他显微镜（AMF、VLM、SEM）的补充。 - 将寻求改进对 NEXAFS 光谱的理论理解。 成分定量的准确性将得到提高。学生将接受执行物理、化学、材料和高分子科学交叉学科研究项目的培训。 对聚合物薄膜的基本了解将得到推进，这可能会改善涂料、粘合剂、润滑剂、油墨和半导体行业中的各种薄膜应用等应用。 其中一部分努力是继续与陶氏化学的长期合作。