School of Civil and Mechanical Engineering, Curtin University, GPO Box U1987, Perth, WA 6845, Australia.
Nanotechnology. 2018 Sep 21;29(38):385701. doi: 10.1088/1361-6528/aacd5d. Epub 2018 Jun 19.
Mechanical properties of polymer nanocomposites depend primarily on nanointerphases as transitional zones between nanoparticles and surrounding matrices. Due to the difficulty in the quantitative characterisation of nanointerphases, previous literature generally deemed such interphases as one-dimensional uniform zones around nanoparticles by assumption for analytical or theoretical modelling. We hereby have demonstrated for the first time direct three-dimensional topography and physical measurement of nanophase mechanical properties between nanodiameter bamboo charcoals (NBCs) and poly (vinyl alcohol) (PVA) in polymer nanocomposites. Topographical features, nanomechanical properties and dimensions of nanointerphases were systematically determined via peak force quantitative nanomechanical tapping mode. Significantly different mechanical properties of nanointerphases were revealed as opposed to those of individual NBCs and PVA matrices. Non-uniform irregular three-dimensional structures and shapes of nanointerphases are manifested around individual NBCs, which can be greatly influenced by nanoparticle size and roughness, and nanoparticle dispersion and distribution. Elastic moduli of nanointerphases were experimentally determined in range from 25.32 ± 3.4 to 66.3 ± 3.2 GPa. Additionally, it is clearly shown that the interphase modulus strongly depends on interphase surface area and interphase volume. Different NBC distribution patterns from fully to partially embedded nanoparticles are proven to yield a remarkable reduction in elastic moduli of nanointerphases.
聚合物纳米复合材料的力学性能主要取决于纳米界面，因为纳米界面是纳米粒子和周围基体之间的过渡区域。由于纳米界面的定量表征具有一定难度，因此之前的文献通常根据分析或理论模型的假设，将纳米界面视为纳米粒子周围的一维均匀区域。在此，我们首次直接对竹炭纳米纤维（NBC）和聚乙烯醇（PVA）在聚合物纳米复合材料中的纳米级机械性能的纳米级相间进行了三维形貌和物理测量。通过峰值力定量纳米力学轻敲模式，系统地确定了形貌特征、纳米力学性能和纳米界面的尺寸。与单个 NBC 和 PVA 基体相比，纳米界面具有明显不同的力学性能。单个 NBC 周围的纳米界面呈现出非均匀的不规则三维结构和形状，这可能受到纳米颗粒尺寸和粗糙度、纳米颗粒分散和分布的极大影响。通过实验确定了纳米界面的弹性模量在 25.32±3.4 到 66.3±3.2 GPa 范围内。此外，很明显，界面模量强烈依赖于界面表面积和界面体积。从完全嵌入到部分嵌入纳米颗粒的不同 NBC 分布模式被证明会显著降低纳米界面的弹性模量。
