High-frequency rheology is a form of mechanical spectroscopy which provides access to fast dynamics in soft materials and hence can give valuable information about the local scale microstructure. It is particularly useful for systems where time-temperature superposition cannot be used, when there is a need to extend the frequency range beyond what is possible with conventional rotational devices. This review gives an overview of different approaches to high-frequency bulk rheometry, i.e. mechanical rheometers that can operate at acoustic (20 Hz–20 kHz) or ultrasound (> 20 kHz) frequencies. As with all rheometers, precise control and know-how of the kinematic conditions are of prime importance. The inherent effects of shear wave propagation that occur in oscillatory measurements will hence be addressed first, identifying the gap and surface loading limits. Different high-frequency techniques are then classified based on their mode of operation. They are reviewed critically, contrasting ease of operation with the dynamic frequency range obtained. A comparative overview of the different types of techniques in terms of their operating window aims to provide a practical guide for selecting the right approach for a given problem. The review ends with a more forward looking discussion of selected material classes for which the use of high-frequency rheometry has proven particularly valuable or holds promise for bringing physical insights.

中文翻译：

---

高频体流变测量：实验方法综述

高频流变学是一种机械光谱学，它提供了对软材料的快速动力学的访问，因此可以提供有关局部尺度微观结构的宝贵信息。当需要将频率范围扩展到超出传统旋转设备可能的范围时，它对于无法使用时间-温度叠加的系统特别有用。本综述概述了高频体流变仪的不同方法，即可以在声学 (20 Hz–20 kHz) 或超声 (> 20 kHz) 频率下运行的机械流变仪。与所有流变仪一样，运动学条件的精确控制和专有技术至关重要。因此，将首先解决在振荡测量中发生的横波传播的固有影响，确定间隙和表面载荷限制。然后根据其操作模式对不同的高频技术进行分类。它们经过严格审查，将操作的简便性与获得的动态频率范围进行对比。根据操作窗口对不同类型技术的比较概述旨在为针对给定问题选择正确方法提供实用指南。审查结束时对选定的材料类别进行了更具前瞻性的讨论，高频流变仪的使用已证明对这些材料类别特别有价值或有望带来物理见解。根据操作窗口对不同类型技术的比较概述旨在为针对给定问题选择正确方法提供实用指南。审查结束时对选定的材料类别进行了更具前瞻性的讨论，高频流变仪的使用已证明对这些材料类别特别有价值或有望带来物理见解。根据操作窗口对不同类型技术的比较概述旨在为针对给定问题选择正确方法提供实用指南。审查结束时对选定的材料类别进行了更具前瞻性的讨论，高频流变仪的使用已证明对这些材料类别特别有价值或有望带来物理见解。