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Thermoresponsive Stability of Colloids in Butyl Acetate/Ethanol Binary Solvent Realized by Grafting Linear Acrylate Copolymers
Langmuir ( IF 3.7 ) Pub Date : 2017-09-07 00:00:00 , DOI: 10.1021/acs.langmuir.7b00301
Lu Jin 1 , Jonas Bemetz 1 , Xia Meng 1 , Hua Wu 1 , Massimo Morbidelli 1
Affiliation  

We have developed a new class of thermoresponsive colloids that can exhibit a sharp reversible transition between dispersion and aggregation in binary BuAc/EtOH solvents based on the UCST (upper critical solution temperature)-type phase separation. This is realized by grafting linear PMMA-BA (random) copolymer onto the colloidal particles. We have selected TiO2/PS hybrid spheres (HSs) as a model system to demonstrate our general design concept. By grafting the linear PMMA-BA copolymer onto the HS surface, with the molecular weight from 30 to 40 kDa, we found that the thermoresponsive transition between dispersion and aggregation is fast, sharp, and reversible. At high mass fractions of the HSs, we have even observed a sharp transition between dispersion and gelation (or phase separation). The transition temperature can be tuned by varying the binary solvent composition, BuAc/EtOH, and the molecular weight of the grafted linear copolymer in the range from 5 to 55 °C. One of the most important features of this work is that the thermoresponsive materials used in organic solvents are initially synthesized in water with widely applied conventional (instead of research-based) techniques, thus being well suited for industrial production. In addition, the proposed approach is rather general and applicable to realizing the thermoresponsive transition for various types of colloids and nanoparticles.

中文翻译:

通过接枝线性丙烯酸酯共聚物实现的乙酸丁酯/乙醇二元溶剂中胶体的热响应稳定性

我们已经开发出新的一类热响应性胶体,它基于UCST(临界温度上限)型相分离,在二元BuAc / EtOH溶剂中的分散和聚集之间表现出明显的可逆转变。这是通过将线性PMMA-BA(无规)共聚物接枝到胶体颗粒上来实现的。我们选择了TiO 2/ PS混合球体(HS)作为模型系统,以展示我们的总体设计概念。通过将线性PMMA-BA共聚物接枝到具有30至40 kDa分子量的HS表面上,我们发现分散和聚集之间的热响应转变是快速,尖锐和可逆的。在高质量分数的HS上,我们甚至观察到了分散和凝胶化(或相分离)之间的急剧转变。可以通过改变二元溶剂组成,BuAc / EtOH和接枝线性共聚物的分子量在5至55°C之间来调节转变温度。这项工作的最重要特征之一是,有机溶剂中使用的热响应性材料最初是通过广泛应用的常规(而不是基于研究的)技术在水中合成的,因此非常适合工业生产。另外,所提出的方法相当通用,并且适用于实现各种类型的胶体和纳米颗粒的热响应转变。
更新日期:2017-09-07
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