Brown Laurie, Koerner Terry, Horton J Hugh, Oleschuk Richard D
Department of Chemistry, Queen's University, Kingston, Ontario, Canada K7L 3N6.
Lab Chip. 2006 Jan;6(1):66-73. doi: 10.1039/b512179e. Epub 2005 Dec 5.
The fabrication of polymer microchips allows inexpensive, durable, high-throughput and disposable devices to be made. Poly(methylmethacrylate) (PMMA) microchips have been fabricated by hot embossing microstructures into the substrate followed by bonding a cover plate. Different surface modifications have been examined to enhance substrate and cover plate adhesion, including: air plasma treatment, and both acid catalyzed hydrolysis and aminolysis of the acrylate to yield carboxyl and amine-terminated PMMA surfaces. Unmodified PMMA surfaces were also studied. The substrate and cover plate adhesion strengths were found to increase with the hydrophilicity of the PMMA surface and reached a peak at 600 kN m(-2) for plasma treated PMMA. A solvent assisted system has also been designed to soften less than 50 nm of the surface of PMMA during bonding, while still maintaining microchannel integrity. The extent to which both surface modifications and solvent treatment affected the adhesion of the substrate to the cover plate was examined using nanoindentation methods. The solvent bonding system greatly increased the adhesion strengths for both unmodified and modified PMMA, with a maximum adhesion force of 5500 kN m(-2) achieved for unmodified PMMA substrates. The bond strength decreased with increasing surface hydrophilicity after solvent bonding, a trend that was opposite to what was observed for non-solvent thermal bonding.
聚合物微芯片的制造能够生产出价格低廉、耐用、高通量且一次性使用的设备。聚甲基丙烯酸甲酯（PMMA）微芯片是通过将微结构热压印到基板上，然后与盖板键合而成。人们研究了不同的表面改性方法以增强基板与盖板之间的附着力，包括：空气等离子体处理，以及对丙烯酸酯进行酸催化水解和氨解，以得到羧基封端和胺基封端的PMMA表面。还对未改性的PMMA表面进行了研究。发现基板与盖板之间的附着力随着PMMA表面亲水性的增加而增强，对于经等离子体处理的PMMA，附着力在600 kN m⁻²时达到峰值。还设计了一种溶剂辅助系统，在键合过程中使PMMA表面不到50 nm的部分软化，同时仍保持微通道的完整性。使用纳米压痕方法研究了表面改性和溶剂处理对基板与盖板附着力的影响程度。溶剂键合系统极大地提高了未改性和改性PMMA的附着力，未改性PMMA基板的最大附着力达到5500 kN m⁻²。溶剂键合后，键合强度随着表面亲水性的增加而降低，这一趋势与非溶剂热键合所观察到 的情况相反。
