Generation of hydrophilic poly(dimethylsiloxane) for high-performance microchip electrophoresis
Generation of hydrophilic poly(dimethylsiloxane) for high-performance microchip electrophoresis
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DOI：
10.1021/ac0609632
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发表时间：
2006-11-01
影响因子：
7.4
通讯作者：
Henry, Charles S.
中科院分区：
文献类型：
--
作者：
Vickers, Jonathan A.;Caulum, Meghan M.;Henry, Charles S.
聚二甲基硅氧烷（PDMS）已成为微芯片毛细管电泳和微流控中应用最广泛的材料之一。这种材料的普及是其低成本、简单制造和坚固的弹性体性能的结果。然而，PDMS的疏水性质限制了其用于微芯片CE、微流体图案化和其他非电泳应用的适用性。使用简单的空气等离子体处理可以使PDMS的表面亲水;然而，通过未反应的低聚物扩散到表面引起的疏水性恢复，这种性质迅速丧失。在这里，提出了一种简单的方法，用于生成在空气中具有长期稳定性的亲水性PDMS。通过简单的两步萃取/氧化过程使PDMS具有亲水性。首先，在一系列溶剂中提取PDMS，这些溶剂被设计成从本体相中除去未反应的低聚物。第二，在简单的空气等离子体中氧化无低聚物的PDMS，产生稳定的亲水性SiO2层。随后用X射线光电子能谱法将表面结合的硅氧烷转化为SiO2。SiO2萃取氧化PDMS在空气中稳定7天相比，小于3小时的原生PDMS。此外，改性PDMS的接触角减小至
Poly(dimethylsiloxane) (PDMS) has become one of the most widely used materials for microchip capillary electrophoresis and microfluidics. The popularity of this material is the result of its low cost, simple fabrication, and rugged elastomeric properties. The hydrophobic nature of PDMS, however, limits its applicability for microchip CE, microfluidic patterning, and other non-electrophoresis applications. The surface of PDMS can be made hydrophilic using a simple air plasma treatment; however, this property is quickly lost through hydrophobic recovery caused by diffusion of unreacted oligomer to the surface. Here, a simple approach for the generation of hydrophilic PDMS with long-term stability in air is presented. PDMS is rendered hydrophilic through a simple two-step extraction/oxidation process. First, PDMS is extracted in a series of solvents designed to remove unreacted oligomers from the bulk phase. Second, the oligomer-free PDMS is oxidized in a simple air plasma, generating a stable layer of hydrophilic SiO2. The conversion of surface-bound siloxane to SiO2 was followed with X-ray photoelectron spectroscopy. SiO2 on extracted-oxidized PDMS was stable for 7 days in air as compared to less than 3 h for native PDMS. Furthermore, the contact angle for modified PDMS was reduced to