Integrated hydrophobic and hydrophilic substrate by nanopatterned surfaces

Controlled integration of hydrophobic and hydrophilic surfaces has shown difficulty due to the challenges of post-treatment processing. In this paper, methods of systematic integration of hydrophobic and hydrophilic surfaces on the same sample are presented. Controlled fabrication of surfaces with different liquid contact angle is achieved. Surface hydrophobic properties have been altered with nanoscale surface patterning using cleanroom semiconductor fabrication techniques. Hydrophobic surfaces are achieved by fabrication of semi-ordered nanoporous surfaces with anodized aluminum oxide (AAO) followed by reactive ionic etching (RIE). Hydrophilic surfaces are made by using nanotexture surface film, made by proper conditions in CF4 RIE. Integration of these two techniques results in simple microfluidic channels from hydrophilic pathways surrounded by hydrophobic surfaces. The results from this paper will be applied for lab-on-chip applications, as efficient pathways for liquid transport.