A rapid method for flow-ready cylindrical microchannel fabrication

Most current methods of microchannel fabrication are expensive and time consuming or result in noncylindrical channels, which is undesirable for many applications. A rapid inexpensive method for the fabrication of flow-ready cylindrical polymer microchannels from polydimethylsiloxane (PDMS) is presented here. In this method, cylindrical needles are used as molds for the channels and also function as flow delivery devices after fabrication. Validation of channel function and smoothness can be accomplished by comparing experimental data to theoretical models. One model was previously developed by the author to predict the incipient motion of a glass sphere in contact with a perfectly smooth PDMS surface and deviations from the model are expected to be a function of channel roughness. The data collected in the present channels show fairly good agreement with the theoretical model, indicating a relatively smooth and consistent surface. In addition, detailed SEM images of the channel showed that the internal surface was qualitatively very smooth.