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Rheology, microrheology and structure of soft materials.

机译：流变学，微流变学和软质材料的结构。

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We study the relationship between the bulk rheological properties and the micron-scale structure and rheology of different types of soft materials. The materials studied are Laponite, a colloidal clay suspension; Carbopol, a dispersion of microgel particles; hydroxyethyl cellulose, a linear polymer solution; and hydrophobically modified hydroxyethyl cellulose, an associative polymer. Bulk properties are measured using conventional shear rheometry. The micron-scale measurements are performed using techniques based on multiple particle tracking and dynamic light scattering. From the thermal motion of suspended tracer particles, we obtain information about the local structure and viscoelastic properties of the materials. We investigate the evolution of Laponite from a liquid to a gel and find that the process is length-scale dependent. We study the properties of Carbopol as a function of microgel concentration and find that as concentration increases, a jamming transition occurs which is related to the onset of yield stress on the bulk scale. We compare the viscoelastic properties of hydroxyethylcellulose and its associative derivative and observe that the hydrophobic interactions in the latter lead to much slower dynamics than in the unmodified polymer. A study of the stress relaxation in hydroxyethylcellulose showed that it depended on both the wait time after the application and removal of a large strain and on the type and magnitude of the deformation applied. Our work exploits the unique ability of microrheological techniques to probe both the rheology and structure of soft materials on the microscopic scale, which enables a better understanding of the relationship between bulk scale properties and microscopic structure in these systems.;Keywords. Rheology, microrheology, soft materials, particle tracking, dynamic light scattering, viscoelasticity, yield stress, gelation, polymers.
机译：我们研究了不同类型的软质材料的整体流变性能与微米级结构和流变性之间的关系。研究的材料是Laponite，一种胶体粘土悬浮液； Carbopol，微凝胶颗粒的分散体；羟乙基纤维素，一种线性聚合物溶液；疏水改性的羟乙基纤维素，一种缔合聚合物。使用常规剪切流变法测量体积性质。使用基于多重粒子跟踪和动态光散射的技术执行微米级测量。从悬浮的示踪剂颗粒的热运动中，我们可以获得有关材料的局部结构和粘弹性的信息。我们调查了Laponite从液体到凝胶的演变过程，发现该过程与长度有关。我们研究了Carbopol作为微凝胶浓度的函数的性质，发现随着浓度的增加，发生了干扰转变，这与在整体规模上屈服应力的发生有关。我们比较了羟乙基纤维素及其缔合衍生物的粘弹性，并观察到后者中的疏水性相互作用比未改性的聚合物中的动力学慢得多。对羟乙基纤维素应力松弛的研究表明，应力松弛既取决于施加和去除大应变后的等待时间，也取决于施加的变形的类型和大小。我们的工作利用微流变技术的独特能力，可以在微观尺度上探测软质材料的流变学和结构，从而可以更好地了解这些系统中的体积尺度特性与微观结构之间的关系。流变学，微流变学，软质材料，颗粒跟踪，动态光散射，粘弹性，屈服应力，胶凝，聚合物。

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