Highly stable surface functionalization of high-aspect-ratio microgas chromatography columns using layer-by-layer self-assembly of sio2 nanoparticles

Abstract

A novel selective surface functionalization of 3D micro-silicon channels using a SiO2 nanoparticles (NPs) coating deposited using Layer-by-Layer (LbL) self-assembly technique is reported here. Additionally, application of SiO2 NPs coating as a stationary phase for chromatographic separation is also presented for the first time. Compared to previously reported techniques, this method enables a simple, low-cost and parallel processing scheme in obtaining homogenous and stable NPs coatings inside the microfluidic channel. Moreover, the reported scheme also provides good repeatability and ease of control over the coating thickness. The SiO2 NPs functionalized microfabricated gas chromatography columns with wide single capillary channels (1 m-long, 150 μm-wide, 240 μm-deep) and very narrow multicapillary channels (25 cm-long, 30 μm-wide, 240 μm-deep, 16 parallel channels) successfully separated a multicomponent gas mixture with a wide range of boiling points.