Capillary kinetics of water in homogeneous, hydrophilic polymeric micro- to nanochannels

Abstract

The capillary kinetics of water inside homogenous PEG micro- to nanochannels formed by replica molding and UV-assisted bonding of a UV-curable PEG polymer is presented. The flow kinetics is measured and compared with that of heterogeneous PDMS channels supported on a glass substrate and having the same channel dimensions. Potential applications to pumpless, analytical tools are tested by flowing a water stream inside a complicated microfluidic network by spontaneous capillary action. The use of a fluorescent solution verified the presence of a concave curvature and complete filling inside the whole complicated PEG channel. The flow rate inside the PEG channel is sufficiently high even for nanochannels with a hydraulic radius of 190 nm. The PEG channel is useful for pumpless, high-speed analytical devices and for studying flow kinetics or dynamics in the micro/nanoscale regime.