Durable Hydrophilic Microchannels with Controlled Morphology by the Direct Molding Method

Abstract

We present a laminated hydrophilic microchannel fabricated by a direct micromolding and facile bonding technique with a hydrophilic organic-inorganic hybrid (HP) resin, which is built into two supporting parallel polydimethylsiloxane (PDMS) substrates. This approach allows one to shape the cross-section of the hydrophilic channel into a regular rectangular or geometrically complicated mouth-throat structure. Spontaneous self-wetting flow of water occurs when water is introduced to the HP microchannel with rectangular cross-section without the aid of mechanical pumping or electric field. The capillary flow velocity can be controlled by varying the channel size. The channel surface behaves like a glass surface in terms of zeta potential for pH larger than 3, and the electro-osmotic flow (EOF) velocity can be as high as 4.7 × 10(-4) cm(2)/V·sec at pH 9.0. The capillary electrophoresis (CE) module made of the HP resin for amino acid or DNA separation is demonstrated to yield a higher resolution in a shorter retention time with repeatability and long-lasting durable performance with antifouling property, when compared with PDMS CE.