One-stage fabrication of sub-micron hydrophilic microchannels on PDMS

A sub-micron hydrophilic microchannel was fabricated on poly(dimethylsiloxane) (PDMS) in one step using vacuum ultraviolet light (VUV) lithography in vacuum. The topographies and properties of the irradiated PDMS surface were characterized and analyzed by atomic force microscopy (AFM), and the chemical composition changes on VUV-treated PDMS analyzed by X-ray photoelectron spectroscopy (XPS). The hydrophilic stability of irradiated PDMS surface was studied by static water contact angle. As demonstrated, the hydrophilicity on surface of PDMS microchannel can be kept for a longer term even three months after the treatment.