Oscillatory nanoindentation of highly compliant hydrogels: A critical comparative analysis with rheometry
Oscillatory nanoindentation of highly compliant hydrogels: A critical comparative analysis with rheometry
复制标题
DOI：
10.1557/jmr.2018.62
复制
发表时间：
2018-04-27
影响因子：
2.7
通讯作者：
Hay, Jennifer
中科院分区：
文献类型：
--
作者：
Akhtar, Riaz;Draper, Emily R.;Hay, Jennifer
我们提出了一种通过振荡纳米压痕测量水凝胶剪切复数模量的方法，对程序和不确定性分析进行了前所未有的关注。通过测试由葡萄糖酸-δ-内酯的受控水解形成的典型低分子量胶凝剂来验证该方法。将纳米压痕结果与使用杯中叶片和平行板夹具通过流变测定法获得的结果进行比较。在 10 Hz 时，通过振荡纳米压痕测量的特性为 G' = 38.1 +/- 2.8 kPa，tan δ = 0.22 +/- 0.02。在相同频率下，通过流变仪测得的性能为 G' = 15.3 +/- 2.9 kPa，tan δ = 0.11 +/- 0.016（叶片杯）和 G' = 7.9 +/- 1.1 kPa，tan δ = 0.05 +/- 0.004（平行板）。纳米压痕测得的剪切模量较大是由于测试规模所致。流变测定法表征了本体材料的响应，而纳米压痕法则探测了凝胶的纤维网络。这里介绍的程序和分析对于其他合规材料（例如水凝胶、软生物组织和食品）的纳米压痕测试很有价值。
We present a method for measuring the shear complex modulus of hydrogels by oscillatory nanoindentation, with unprecedented attention to procedure and uncertainty analysis. The method is verified by testing a typical low-molecular-weight gelator formed from the controlled hydrolysis of glucono-delta-lactone. Nanoindentation results are compared with those obtained by rheometry using both vane-in-cup and parallel-plate fixtures. At 10 Hz, the properties measured by oscillatory nanoindentation were G' = 38.1 +/- 2.8 kPa, tan delta = 0.22 +/- 0.02. At the same frequency, the properties measured by rheometry were G' = 15.3 +/- 2.9 kPa, tan delta = 0.11 +/- 0.016 (vane-in-cup) and G' = 7.9 +/- 1.1 kPa, tan delta = 0.05 +/- 0.004 (parallel-plate). The larger shear modulus measured by nanoindentation is due to the scale of testing. Whereas rheometry characterizes the bulk material response, nanoindentation probes the fibrous network of the gel. The procedure and analysis presented here are valuable for nanoindentation testing of other compliant materials such as hydrogels, soft biological tissue, and food products.