Surface engineering of poly(dimethylsiloxane) microfluidic devices using transition metal sol-gel chemistry
Surface engineering of poly(dimethylsiloxane) microfluidic devices using transition metal sol-gel chemistry
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DOI：
10.1021/la053085w
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发表时间：
2006-04-25
期刊：
影响因子：
3.9
通讯作者：
Culbertson, CT
中科院分区：
文献类型：
--
作者：
Roman, GT;Culbertson, CT
我们报告的涂层聚（二甲基硅氧烷）（PDMS）微通道使用过渡金属溶胶-凝胶化学和随后的表征涂层。使用软聚合物光刻产生的通道，并研究了三种金属醇盐溶胶-凝胶前体，异丙醇钛，异丙醇锆和三异丁醇氧化钒。金属醇盐扩散到PDMS通道的侧壁中，随后使用水蒸气水解。该过程导致形成二氧化钛、氧化锆或氧化钒的耐用金属氧化物表面。使用接触角、X射线光电子能谱（XPS）、拉曼、透射电子显微镜（TEM）、扫描电子显微镜（SEM）、原子力显微镜（AFM）和电渗迁移率（EOM）测量对所得表面进行表征。所有的金属氧化物改性的PDMS表面的亲水性比天然的PDMS显着。涂层的接触角对于PDMS-ZrO 2为90度，对于PDMS-TiO 2为61度，对于PDMS-vanadia为19度。XPS显示PDMS表面上存在二氧化钛、氧化锆和氧化钒。XPS光谱还显示，在PDMS的Si-O、Si-C或C-H键中原位沉积颗粒后，PDMS没有化学改性。原位沉积的颗粒用TEM成像，发现其均匀地分布在整个PDMS块体中。无机涂层的EOM测量在至少95天的时间内是稳定的。根据所用缓冲液的pH值，可以产生阴极和阳极EOM。PDMS-TiO 2、PDMS-ZrO 2和PDMS-vanadia通道的净零电荷点使用EOM对pH测量来计算，并且发现分别为4.1 +/- 0.25、6.1 +/- 0.2和7.0 +/- 0.43。除了用无机涂层修饰PDMS通道之外，这些无机涂层还使用硅烷化学用各种有机官能团衍生化，所述有机官能团包括低聚环氧乙烷（OEO）、氨基、全氟或巯基。接触角测量全氟，巯基，氨基，和OEO涂覆的表面分别产生的接触角为120，76，45，和23。这些接触角在95天内没有变化。OEO涂层通道将EOM从天然PDMS-TiO 2降低50%至0.9 +/- 0.05 x 10（-4）cm（2）/V.s（n = 5，5.5%RSD）。
We report the coating of poly(dimethylsiloxane) (PDMS) microchannels using transition metal sol-gel chemistry and the subsequent characterization of the coatings. The channels were created using soft polymer lithography, and three metal alkoxide sol-gel precursors were investigated, titanium isopropoxide, zirconium isopropoxide, and vanadium triisobutoxide oxide. The metal alkoxides were diffused into the sidewalls of a PDMS channel and subsequently hydrolyzed using water vapor. This procedure resulted in the formation of durable metal oxide surfaces of titania, zirconia, or vanadia. The resulting surfaces were characterized using contact angle, X-ray photoelectron spectroscopy (XPS), Raman, transmission electron microscopy (TEM), scanning electron microscopy (SEM), atomic force microscopy (AFM), and electroosmotic mobility (EOM) measurements. All of the metal oxide-modified PDMS surfaces were significantly more hydrophilic than native PDMS. Contact angles for the coatings were 90 for PDMS-ZrO2, 61 degrees for PDMS-TiO2, and 19 for PDMS-vanadia. XPS showed the presence of titania, zirconia, and vanadia on the PDMS surface. XPS spectra also showed no chemical modification of the PDMS after the in situ deposition of the particles either in the Si-O, Si-C, or C-H bonds of the PDMS. The particles deposited in situ were imaged with TEM and were found to be homogeneously distributed throughout the bulk of the PDMS. EOM measurements of the inorganic coatings were stable over a period of at least 95 days. Both cathodic and anodic EOMs could be generated depending upon buffer pH used. The points of net zero charge for PDMS-TiO2, PDMS-ZrO2, and PDMS-vanadia channels were calculated using EOM versus pH measurements and were found to be 4.1 +/- 0.25, 6.1 +/- 0.2, and 7.0 +/- 0.43; respectively. In addition to modifying PDMS channels with inorganic coatings, these inorganic coatings were derivatized with various organic functionalities including oligoethylene oxide (OEO), amino, perfluoro, or mercapto groups using silane chemistry. Contact angle measurements for perfluoro, mercapto, amino, and OEO-coated surfaces yielded contact angles of 120, 76, 45, and 23, respectively. These contact angles did not change over the period of 95 days. OEO-coated channels reduced the EOM by 50% from native PDMS-TiO2 to 0.9 +/- 0.05 x 10(-4) cm(2)/V.s (n = 5, 5.5% RSD).