Long Timothy M, Prakash Shaurya, Shannon Mark A, Moore Jeffrey S
Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
Langmuir. 2006 Apr 25;22(9):4104-9. doi: 10.1021/la052977t.
Separation rates and resolutions within capillary electrophoretic (CE) systems can be enhanced when surface zeta potentials are uniform with minimum deviations from ideal pluglike flow. Microfluidic CE devices based on poly(methyl methacrylate) (PMMA) are being developed due to the optical clarity, availability, stability, and reproducible electroosmotic flow (EOF) rates displayed by this polymer. Control of EOF in polymer-based CE systems can be achieved by surface zeta potential alteration through chemical modification. Herein, a method will be presented for the surface functionalization of PMMA with chemistry analogous to formation of trichlorosilane self-assembled monolayers on SiO2. The current method involves two separate steps. First, surface activation with water-vapor plasma introduces surface hydroxylation. Second, treatment of the plasma-treated PMMA with a substituted trichlorosilane solution forms the functional surface layer. The modified surfaces were characterized using several analytical techniques, including water contact angle, X-ray photoelectron spectroscopy, Fourier transform infrared-attenuated total reflection, secondary ion mass spectroscopy, and measurement of EOF velocities within PMMA microchannels.
当表面zeta电位均匀且与理想的塞状流的偏差最小时，毛细管电泳（CE）系统中的分离速率和分辨率可以提高。基于聚甲基丙烯酸甲酯（PMMA）的微流控CE装置正在被开发，因为这种聚合物具有光学透明度、可用性、稳定性和可重现的电渗流（EOF）速率。通过化学修饰改变表面zeta电位，可以实现基于聚合物的CE系统中EOF的控制。本文将介绍一种对PMMA进行表面功能化的方法，其化学过程类似于在SiO2上形成三氯硅烷自组装单分子层。目前的方法包括两个独立的步骤。首先，用水蒸气等离子体进行表面活化，引入表面羟基化。其次，用取代的三氯硅烷溶液处理经等离子体处理的PMMA，形成功能表面层。使用几种分析技术对改性表面进行了表征，包括水接触角、X射线光电子能谱、傅里叶变换红外衰减全反射、二次离子质谱以及测量PMMA微通道内的EOF速度。
