School of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
J Microencapsul. 2012;29(3):277-85. doi: 10.3109/02652048.2011.646331. Epub 2012 Jan 4.
Microspheres, including microcapsules and cells or beads, are widely used to produce many functional products. Information about their mechanical properties is essential to understanding their performance during manufacturing, processing and end-use applications. The mechanical characterization of microspheres requires applying a mechanical load onto single microspheres and measuring the corresponding deformation, and theoretical modelling of the force-deformation relationship, which allows the determination of mechanical property parameters of the materials such as the elastic modulus, yield stress or failure stress/strain. This review presents the techniques developed for the characterization of microspheres, but focus is on the two most common techniques: atomic force microscopy and compression testing by micromanipulation. The merits and limitations of these techniques and their future developments required are discussed along with the four key aspects to mechanically characterize single microspheres: (i) elastic regime, (ii) plasticity, (iii) rupture behaviour and (iv) time-dependent effects, such as viscoelasticity and permeation.
微球，包括微胶囊和细胞或珠粒，被广泛用于生产许多功能性产品。了解它们在制造、加工和最终用途应用过程中的机械性能是至关重要的。微球的机械特性表征需要将机械载荷施加到单个微球上，并测量相应的变形，以及对力-变形关系进行理论建模，这使得可以确定材料的机械性能参数，如弹性模量、屈服应力或失效应力/应变。本综述介绍了用于微球特性表征的技术，但重点介绍了两种最常见的技术：原子力显微镜和微操作压缩测试。讨论了这些技术的优点和局限性以及它们未来发展所需的方向，以及机械表征单个微球的四个关键方面：（i）弹性区，（ii）塑性，（iii）破裂行为，（iv）时变效应，如粘弹性和渗透。
