Water-Dependent Micromechanical and Rheological Properties of Silica Colloidal Crystals Studied by Nanoindentation
Water-Dependent Micromechanical and Rheological Properties of Silica Colloidal Crystals Studied by Nanoindentation
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DOI：
10.1021/nl3024998
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发表时间：
2012-09-01
期刊：
影响因子：
10.8
通讯作者：
Lopez, Cefe
中科院分区：
文献类型：
--
作者：
Gallego-Gomez, Francisco;Morales-Florez, Victor;Lopez, Cefe
在这里，我们展示了纳米压痕技术详细研究二氧化硅胶体晶体（CC）微观力学响应的适用性。位移小于亚微米球体尺寸的敏感性，即使解决离散事件和表面的功能，揭示微粒功能与原子晶体的类比。显着的鲁棒性，长范围的结构变形，和大的能量dissipation. Easy实现的温度/速率依赖的纳米压痕量化的吸附水赋予二氧化硅CC的湿颗粒材料的性质，如粘塑性的最重要的作用。通过用石英颈代替毛细管桥，制备了一种新型的“非颗粒”CC，以直接测试与水无关的机械响应。二氧化硅碳纳米管，作为特定的（纳米，有序的）湿颗粒组装与明确的配置，可能是有用的模型系统的颗粒科学和毛细管凝聚力在纳米尺度上。
Here we show the suitability of nanoindentation to study in detail the micromechanical response of silica colloidal crystals (CCs). The sensitivity to displacements smaller than the submicrometer spheres size, even resolving discrete events and superficial features, revealed particulate features with analogies to atomic crystals. Significant robustness, long-range structural deformation, and large energy dissipation were found. Easily implemented temperature/rate-dependent nanoindentation quantified the paramount role of adsorbed water endowing silica CCs with properties of wet granular materials like viscoplasticity. A novel "nongranular" CC was fabricated by substituting capillary bridges with silica necks to directly test water-independent mechanical response. Silica CCs, as specific (nanometric, ordered) wet granular assemblies with well-defined configuration, may be useful model systems for granular science and capillary cohesion at the nanoscale.