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arXiv 1306.5613cond-mat.softcond-mat.mes-hallcond-mat.mtrl-sci
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锂皂石水悬浮液老化过程中的物理化学效应

Physicochemical Effects in Aging Aqueous Laponite Suspensions

A. Shahin, Yogesh M Joshi

摘要:

我们通过进行广泛的流变学和电导率实验,研究了Laponite水悬浮液的老化行为作为Laponite浓度、盐浓度、自悬浮液制备以来所经过的时间(空闲时间)和温度的函数。我们观察到,时间演变的弹性模量,它描述了结构的建设和老化,转移到低的时间进行的实验,为更高浓度的锂皂石,更高浓度的盐,更高的温度和更高的空闲时间,同时保持在固体政权的曲率演变。因此,弹性模量在固体状态下的演变的适当移动导致老化时间、闲置时间、盐浓度、锂皂石浓度、温度的叠加。这种叠加的存在表明,无论所述变量在探索范围内的微观结构建设的一般性质。获得叠加所需的移位因子的行为表明,与结构建立相关的能垒随着空闲时间和温度的增加而降低;并且随着锂皂石和盐的浓度的增加而线性降低。电导率实验表明,悬浮液的离子电导率随着锂皂石浓度、盐浓度、温度的增加而增加,并且非常重要的是随着闲置时间的增加而增加。我们还使用DLVO理论分析了粒子间的相互作用,该理论表明,当粒子以平行方式彼此接近时,空闲时间、温度和盐浓度的增加会增加排斥能垒的高度,同时减小排斥能垒的宽度。流变学和电导率实验分析表明,在Laponite的水悬浮液的低能结构的吸引相互作用的强烈影响。

英文摘要:

We study aging behavior of aqueous suspension of Laponite as a function of concentration of Laponite, concentration of salt, time elapsed since preparation of suspension (idle time) and temperature by carrying extensive rheological and conductivity experiments. We observe that temporal evolution of elastic modulus, which describes structural buildup and aging, shifts to low times for experiments carried out for higher concentration of Laponite, higher concentration of salt, greater temperature and on higher idle time while preserving the curvature of evolution in the solid regime. Consequently appropriate shifting of evolution of elastic modulus in the solid regime leads to aging time idle time salt concentration Laponite concentration temperature superposition. Existence of such superposition suggests generic nature of microstructure buildup irrespective of mentioned variables in the explored range. Behavior of shift factors needed to obtain the superposition indicate that energy barrier associated with structural buildup decreases with increase in idle time and temperature; and decreases linearly with increase in concentration of Laponite and that of salt. The conductivity experiments show that ionic conductivity of the suspension increases with increasing Laponite concentration, salt concentration, temperature and very importantly the idle time. We also analyze the interparticle interactions using DLVO theory that suggests increase in idle time, temperature and salt concentration increases height of repulsive energy barrier while decreases width of the same when particles approach each other in a parallel fashion. Analysis of rheological and conductivity experiments suggest strong influence of attractive interactions on the low energy structures in aqueous suspension of Laponite.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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