Presidential Young Investigator Award: Sub-Triple Liquids and Crystallization in Supercritical Fluids

总统青年研究员奖：超临界流体中的亚三重液体和结晶

• 批准号: 8657010
• 负责人: Pablo Debenedetti
• 金额: $ 31.18万
• 依托单位: Princeton University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-03-01 至 1992-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8657010&HistoricalAwards=false
• 关键词: Presidential; Young; Investigator; Award; Sub

Research Summary: Sub-triple liquids (metastable liquids below their triple point): This project includes an experimental study of the phase transition (unique to sub-triple liquids) involving simultaneous boiling and crystallization, completion of a theoretical study of tensile instability (loss of tensile strength), and investigation of the molecular origin of density anomalies (liquids which contract when heated). The connection between tensile instability and density anomalies was derived by the PI. Crystallization in supercritical fluids: This portion of the project involves completion of equipment construction and preliminary experiments in which continuous precipitation occurs into a fluid whose temperature, pressure, and composition can be independently manipulated. Novelty/Innovation: Sub-triple liquids are an unexplored state of matter (the term was coined by the PI). Their behavior includes tensile instabilities (a decrease in tensile strength as the temperature is lowered, an experimentally observed anomaly first explained by the PI) and a phase transition involving rapid crystallization and boiling coupled with liquid disappearance, a phenomenon not to be found elsewhere in nature. Crystallization from supercritical fluids is a novel method for the production of uniform crystals and monodisperse polymer particles. The most innovative concept in this project is the attainment of uniform, controllable conditions within the fluid where nucleation occurs through a manipulation of pressure instead of temperature. Pressure perturbations travel at the speed of sound, thus guaranteeing uniformity throughout the fluid medium and are applied to a highly compressible fluid near its critical point, thus giving rise to large changes in density and hence solvent power. Technical Impact/Practical Significance: Tension generated when a degassed liquid is cooled inside a rigid container is ideally suited for the non-destructive testing of adhesion on flat surfaces. This is a problem of vital importance in microchip manufacture (e.g., photo-resist adhesion testing). The experimentally observed equilibrium of a sub-triple liquid and a crystal suggests the novel idea of creating solids which are uniformly stressed. Since it is otherwise impossible to subject a solid to isotropic tension, this process (tension crystallization) could lead to the production of materials with unique properties.

研究摘要：亚三重液体（以下为亚稳液体） 三重点）：该项目包括一项实验研究 的相变（独特的亚三重液体），涉及 同时沸腾和结晶，完成 拉伸失稳的理论研究 强度），并调查密度的分子起源 异常（液体加热时收缩）。 连接 张力不稳定性和密度异常之间的关系， PI。 超临界流体中的结晶：这一部分 该项目包括完成设备建设， 进行连续降水的初步实验 其温度、压力和成分可以 独立操作。 新奇/创新：亚三重液体是一种未探索的状态 ”（《说文》：“事”，“事”也。 他们的行为 包括拉伸不稳定性（当拉伸强度降低时， 温度降低，这是实验观察到的异常现象， 首先由PI解释）和涉及快速的相变 结晶和沸腾加上液体消失， 在自然界其他地方找不到的现象。 结晶 从超临界流体是一种新的方法， 均匀的晶体和单分散的聚合物颗粒。 最 该项目的创新概念是实现统一， 在流体内发生成核的可控条件 通过控制压力而不是温度。 压力扰动以音速传播，因此 保证整个流体介质的均匀性， 应用于临界点附近的高度可压缩流体， 从而引起密度和溶剂的大变化 动力. 技术影响/实际意义： 脱气液体在刚性容器内冷却， 适用于平板附着力的无损检测 表面。 这是微芯片中一个至关重要的问题 制造（例如，光致抗蚀剂粘附测试）。 的 实验观察到的亚三重液体和 水晶提出了创造固体的新想法， 均匀地强调。 因为不这样就不可能 一个固体向各向同性的张力，这个过程（张力 结晶）可能导致材料的生产， 独特的属性。