Boots J N M, Fokkink R, van der Gucht J, Kodger T E
Physical Chemistry and Soft Matter, Wageningen University and Research, Stippeneng 4, 6708WE Wageningen, The Netherlands.
Rev Sci Instrum. 2019 Jan;90(1):015108. doi: 10.1063/1.5043628.
We present the development of a multi-position indentation setup capable of spatially mapping mechanically heterogeneous materials. A detailed description of the indentation instrumentation is first provided, emphasizing force sensitivity, noise reduction, and signal fidelity. We first present indentation experiments on soft hydrogels that are submerged in water and show how the large contributions to the measured force due to the air-water surface tension can be avoided. The displacement field of the indented hydrogel is visualized using fluorescently coated microspheres embedded in the hydrogel, allowing simultaneous mapping of the stress and strain fields for a soft polymer network. We then fabricate a polymer network with patterned elasticity using halftone UV lithography and map the elastic modulus with the multi-position indentation instrument. The applied UV pattern is found back in the measured elastic modulus map, showing the capability of the multi-position indentation setup to map mechanically heterogeneous polymer networks.
我们展示了一种能够对机械性能不均匀材料进行空间映射的多位置压痕装置的开发。首先详细介绍了压痕仪器，重点强调了力灵敏度、降噪和信号保真度。我们首先展示了在水中浸没的软水凝胶上进行的压痕实验，并说明了如何避免由于空气 - 水表面张力对测量力产生的巨大影响。使用嵌入水凝胶中的荧光涂层微球可视化压痕水凝胶的位移场，从而能够同时绘制软聚合物网络的应力和应变场。然后，我们使用半色调紫外光刻技术制造具有图案化弹性的聚合物网络，并用多位置压痕仪器绘制弹性模量图。在所测量的弹性模量图中可以找到所施加的紫外图案，这表明多位置压痕装置能够绘制机械性能不均匀的聚合物网络。
