Structural and rheological aging in model attraction-driven glasses by Rheo-SANS,Soft Matter

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Structural and rheological aging in model attraction-driven glasses by Rheo-SANS
Soft Matter ( IF 2.9 ) Pub Date : 2020-11-23 , DOI: 10.1039/d0sm01373k
Melissa B. Gordon _{1,

1,

2,

3,

4} , Christopher J. Kloxin _{1,

4,

5,

6,

7} , Norman J. Wagner _{1,

4,

5,

6,

7}

Affiliation

Aging in a model colloidal suspension comprised of particles with a thermoreversible attraction is studied using Rheo-SANS techniques in the attractive-driven glass state. Multiple thermal pathways lead to a common rheological and microstructural aging trajectory, as was observed previously for a thermoreversible gel. SANS measurements of the colloidal glass microstructure as a function of temperature and time during various quench protocols are quantitatively characterized in terms of an effective interaction strength that becomes an order parameter defining the microstructural state of the glass. Using previously validated concepts of a fictive temperature, a semi-empirical, quantitative relationship similar to an Avrami relationship is established between the mechanical aging (elastic modulus) and microstructural aging (order parameter) that is independent of thermal history for the thermal profiles studied herein at long times. Furthermore, shear rejuvenation is studied, and while shear may only partially reduce the degree of structure in the glass, aging upon flow cessation is found to follow a common trajectory when viewed in terms of the microstructural order parameter.

中文翻译：

Rheo-SANS在模型吸引驱动玻璃中的结构和流变老化

使用Rheo-SANS技术在吸引驱动的玻璃态下研究了由具有热可逆吸引力的颗粒组成的模型胶体悬浮液的老化过程。多个热通道导致共同的流变学和微观结构老化轨迹，如先前对于热可逆凝胶所观察到的。胶体玻璃微观结构随温度和时间变化而变化的SANS测量值，根据有效相互作用强度进行定量表征，有效相互作用强度成为定义玻璃显微结构状态的有序参数。使用先前验证的虚拟温度概念，半经验，在机械老化（弹性模量）和微观结构老化（有序参数）之间建立了与Avrami关系相似的定量关系，该关系与本文中长期研究的热曲线的热历史无关。此外，还研究了剪切振兴，虽然剪切可能仅部分降低玻璃的结构程度，但从微观结构有序参数来看，发现停流时的老化遵循共同的轨迹。

更新日期：2020-11-27

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