Fabrication and optical properties of zirconia nanoparticle array on a patterned hydrophilic-hydrophobic substrate

Abstract

This study presents a convenient method for nanoparticles (NPs) patterning with high controllability of the number of NPs. Dot-array of zirconia (ZrO2) NPs were fabricated on a microcontact printed hydrophilic-hydrophobic substrate without any post-functionalization on ZrO2 NPs. Because the substrate has hydrophilic patterns with hydrophobic passivation, ZrO2 colloids in de-ionized water were selectively deposited on the substrate; thus, an “electrostatic approach” by functionalization of ZrO2 NPs is not required. In addition, the number of patterned NPs was controllable by size of hydrophilic area, deposition time, and concentration of colloidal NPs. The number of NPs increases over ten times as the size of polydimethylsiloxane (PDMS) dot stamp increase from 5 to 10 μm in diameter, while it increases twice and four times by increasing deposition time (1 to 60 min) and concentration of NPs colloidal solution (16 to 57 mM), respectively. Moreover, ellipsometric reflectance of the dot-arrays of ZrO2 NPs patterned with different concentrations of NP solutions was measured and discussed in comparison with the absorbance spectrum of a powder sample of ZrO2 NPs.