Extraction of Silicone Uncrosslinked Chains at Air-Water-Polydimethylsiloxane Triple Lines
Extraction of Silicone Uncrosslinked Chains at Air-Water-Polydimethylsiloxane Triple Lines
复制标题
DOI：
10.1021/acs.langmuir.8b02128
复制
发表时间：
2018-10-16
期刊：
影响因子：
3.9
通讯作者：
Neukirch, Sebastien
中科院分区：
文献类型：
--
作者：
Hourlier-Fargette, Aurelie;Dervaux, Julien;Neukirch, Sebastien
聚二甲基硅氧烷(PDMS)等有机硅弹性体是实验室中常规使用的方便材料，它结合了易制备性、灵活性、透明性和透气性。然而，众所周知，这些弹性体含有一小部分未交联低分子量齐聚物，其影响尚不完全清楚，特别是在与液体接触时。在这里，我们表明，涉及空气、水和PDMS弹性体的三重线通过毛细诱导萃取机制导致未交联型有机硅低聚物对水-空气界面的污染。我们研究了静态接触线和运动接触线的情况，并研究了从部分浸没的PDMS板到沉积在PDMS板上的水滴或气泡的各种几何形状，所有这些都涉及空气-水-弹性体三重线。我们通过实验证明，移动接触线的污染时间比静态情况下的短得多。最后，我们提出了一个简单的孔弹性模型，该模型反映了实验中观察到的污染的主要特征。
Silicone elastomers such as polydimethylsiloxane (PDMS) are convenient materials routinely used in laboratories that combine ease of preparation, flexibility, transparency, and gas permeability. However, these elastomers are known to contain a small fraction of uncrosslinked low-molecular-weight oligomers, the effects of which are not completely understood, particularly when used in contact with liquids. Here, we show that triple lines involving air, water, and PDMS elastomers are responsible for the contamination of water-air interfaces by uncrosslinked silicone oligomers through a capillarity-induced extraction mechanism. We investigate both the case of static and moving contact lines and study various geometries ranging from partially immersed PDMS plates to water droplets or air bubbles deposited on PDMS plates, all involving air-water-elastomer triple lines. We demonstrate experimentally that the contamination timescale is strikingly shorter for moving contact lines than in the static case. Eventually, we propose a simple poroelastic model capturing the main features of contamination observed in experiments.