Single-Particle Tracking To Probe the Local Environment in Ice-Templated Crosslinked Colloidal Assemblies.
Single-Particle Tracking To Probe the Local Environment in Ice-Templated Crosslinked Colloidal Assemblies.
复制标题
单粒子追踪探测冰模板交联胶体组件中的局部环境。
DOI：
10.1021/acs.langmuir.7b04120
复制
发表时间：
2018
期刊：
影响因子：
3.9
通讯作者：
G. Kumaraswamy
中科院分区：
文献类型：
--
作者：
Karthika Suresh;D. Sharma;Ramya Chulliyil;K. Sarode;V. Ravi Kumar;Arindam Chowdhury;G. Kumaraswamy
我们使用单粒子跟踪研究胶体动力学的混合组装体，包括胶体陷入交联聚合物网络。这些组件是使用冰模板制备的，并且是大孔整体结构。我们调查的组装，化学上相同，但表现出不同的机械响应的微观结构和性能的关系。具体来说，我们对比弹性组件，可以从大的压缩变形恢复与塑料组件，被压缩失败。颗粒跟踪提供了微观结构差异的见解，这些差异是弹性和塑性组件的不同机械响应的基础。由于这些组件中的胶体运动是缓慢的，因此颗粒跟踪对成像伪影（例如载物台漂移）特别敏感。我们表明，使用小波变换应用到荧光显微镜的探针粒子的轨迹消除阶段漂移，允许约2 nm的空间分辨率。在弹性和塑料支架中，探针颗粒被其他颗粒包围，因此它们的运动被束缚住。我们提出了均方位移和货车霍韦分布的颗粒运动，并表明，塑料组件的特点是显着更大的空间异质性相比，弹性海绵。在弹性组件中，颗粒扩散率在平均值附近达到峰值，而在塑料组件中，扩散率分布很广，没有明显的峰值。弹性和塑性组件都显示出与频率无关的固体模量，从颗粒跟踪微观流变学。在这里，也有一个更广泛的分布的模量值的塑料支架相比，弹性，在体流变测量，其中两个组件表现出类似的响应。我们解释我们的结果在胶体组件中的聚合物网格中的交联的空间分布。
We use single-particle tracking to investigate colloidal dynamics in hybrid assemblies comprising colloids enmeshed in a crosslinked polymer network. These assemblies are prepared using ice templating and are macroporous monolithic structures. We investigate microstructure-property relations in assemblies that appear chemically identical but show qualitatively different mechanical response. Specifically, we contrast elastic assemblies that can recover from large compressive deformations with plastic assemblies that fail on being compressed. Particle tracking provides insights into the microstructural differences that underlie the different mechanical response of elastic and plastic assemblies. Since colloidal motions in these assemblies are sluggish, particle tracking is especially sensitive to imaging artifacts such as stage drift. We demonstrate that the use of wavelet transforms applied to trajectories of probe particles from fluorescence microscopy eliminates stage drift, allowing a spatial resolution of about 2 nm. In elastic and plastic scaffolds, probe particles are surrounded by other particles-thus, their motion is caged. We present mean square displacement and van Hove distributions for particle motions and demonstrate that plastic assemblies are characterized by significantly larger spatial heterogeneity when compared with the elastic sponges. In elastic assemblies, particle diffusivities are peaked around a mean value, whereas in plastic assemblies, there is a wide distribution of diffusivities with no clear peak. Both elastic and plastic assemblies show a frequency independent solid modulus from particle tracking microrheology. Here too, there is a much wider distribution of modulus values for plastic scaffolds as compared to elastic, in contrast to bulk rheological measurements where both assemblies exhibit a similar response. We interpret our results in terms of the spatial distribution of crosslinks in the polymer mesh in the colloidal assemblies.