Multiple particle tracking microrheology measured using bi-disperse probe diameters
Multiple particle tracking microrheology measured using bi-disperse probe diameters
复制标题
使用双分散探针直径测量多粒子跟踪微流变学
DOI：
10.1039/c8sm01098f
复制
发表时间：
2018
期刊：
影响因子：
3.4
通讯作者：
Schultz, Kelly M.
中科院分区：
文献类型：
--
作者：
Wehrman, Matthew D.;Lindberg, Seth;Schultz, Kelly M.
多粒子跟踪流变学（MPT）是定量表征软物质流变特性的有力工具。传统上，MPT使用单一粒度来表征流变性能。但在复杂系统中，对单一尺寸颗粒的MPT测量可以表征与材料的长度尺度相关结构相关的不同性质。通过改变探针的尺寸，MPT可以测量材料中与不同长度尺度相关的特性。我们开发了一种技术，同时跟踪一个双分散人口的探针粒子。0.5和2 μm颗粒嵌入在同一样品中，并使用基于亮度的平方回转半径Rg 2分别跟踪这些颗粒群。通过测量不同浓度甘油样品的粘度来验证双分散MPT。双分散MPT测量与文献值吻合良好。然后，该技术表征均匀的聚（乙二醇）-丙烯酸酯：聚（乙二醇）-二硫醇凝胶。临界松弛指数和临界凝胶化时间是一致的，并同意与以前的测量使用一个单一的粒子。最后，降解的非均相氢化蓖麻油胶体凝胶的特点。这两种颗粒尺寸测量的临界弛豫指数值不同，表明它们探测的是不同的结构。材料的异质性分析表明，测量的异质性是依赖于探针的大小，表明每个颗粒测量的长度尺度依赖的结构的流变学演变。总的来说，双分散MPT增加了单次测量中获得的信息量，从而能够更完整地表征从消费者护理产品到生物材料的复杂系统。
Multiple particle tracking microrheology (MPT) is a powerful tool for quantitatively characterizing rheological properties of soft matter. Traditionally, MPT uses a single particle size to characterize rheological properties. But in complex systems, MPT measurements with a single size particle can characterize distinct properties that are linked to the materials' length scale dependent structure. By varying the size of probes, MPT can measure the properties associated with different length scales within a material. We develop a technique to simultaneously track a bi-disperse population of probe particles. 0.5 and 2 μm particles are embedded in the same sample and these particle populations are tracked separately using a brightness-based squared radius of gyration, Rg2. Bi-disperse MPT is validated by measuring the viscosity of glycerol samples at varying concentrations. Bi-disperse MPT measurements agree well with literature values. This technique then characterizes a homogeneous poly(ethylene glycol)-acrylate:poly(ethylene glycol)-dithiol gelation. The critical relaxation exponent and critical gelation time are consistent and agree with previous measurements using a single particle. Finally, degradation of a heterogeneous hydrogenated castor oil colloidal gel is characterized. The two particle sizes measure a different value of the critical relaxation exponent, indicating that they are probing different structures. Analysis of material heterogeneity shows measured heterogeneity is dependent on probe size indicating that each particle is measuring rheological evolution of a length scale dependent structure. Overall, bi-disperse MPT increases the amount of information gained in a single measurement, enabling more complete characterization of complex systems that range from consumer care products to biological materials.