Superposition 'Chirp' Rheometry: a new technique for the rapid rheological characterisation of complex fluids with transient microstructures.

复杂流体的流动和变形特性（即流变学），由于流体的微观结构而产生，通常是实现产品功能的关键因素。在这种情况下，“产品”的范围可以从使用功能性油墨制造的印刷电子元件到生理过程的“生物产品”，例如血液凝固-即血凝块。然而，复杂的流动条件（其是“过程”固有的）对流体微观结构的影响以及因此对流动性质的影响难以研究-特别是如果过程是动态的（例如，其中样品正在经历固化、凝胶化、凝结、干燥等）。该研究提案旨在开发，测试和演示一种新的技术，用于表征响应于流动条件而发生的流动敏感复杂流体的流变学（和微观结构）变化。建议开发一种技术，该技术使用“啁啾”波形（即频率调制波形）来探测流体在经历流动时的时间相关流动和变形特性。该项目的成功交付将为工业和学术流变学家、产品配方专家、制造商和工艺设计师提供（i）一种非常强大的工具，用于快速表征持续剪切流引起的流变/微观结构变化，（ii）对单向应力下凝胶化微观结构后果的新见解，和（iii）解释平行叠加流变数据的框架。

The flow and deformation properties (i.e. the Rheology) of complex fluids, which arise due to the fluids microstructure, are often a critical factor in achieving a product functionality. In this context, "products" may range from printed electronic components manufactured using functional inks, to the 'biological products' of physiological processes such as blood coagulation - i.e. the blood clot. However, the effect of complex flow conditions (which are inherent to the 'process') on the fluid microstructure, and hence flow properties, is difficult to study - especially if the process is dynamic (e.g. where the sample is undergoing curing, gelation, clotting, drying etc). This research proposal aims to develop, test and demonstrate a novel technique for characterising changes in the rheology (and microstructure) of flow-sensitive complex fluids occurring in response to a flow condition. It is proposed to develop a technique which uses 'chirp' waveforms (i.e. frequency modulated waveforms) to probe the time-dependent flow and deformation properties of fluids as they are experiencing flow. Successful delivery of the project will provide industrial and academic rheologists, product formulation specialists, manufacturers and process designers with (i) an extremely powerful tool for rapidly characterising rheological/microstructural changes occurring in response to a sustained shear flow, (ii) new insights into the microstructural consequences of gelation under unidirectional stress, and (iii) a framework for interpreting parallel superposition rheometric data.