In this work, the effect of lacquer type was studied. Three types
of acrylic lacquer were investigated, including paint lacquer, matte
spray lacquer and gloss spray lacquer. For paint lacquer, the paper
was painted with paint lacquer instead of spraying. The results
indicated that it was inappropriate for fabrication of pattern on
paper because the penetration of lacquer into the filter paper and
the diffusion under the iron mask could not be controlled (Fig. 3a).
To study the matte spray lacquer and gloss spray lacquer, the
spraying method was used as the lacquer application method.
With the matte spray lacquer (Fig. 3b), the hydrophobic and
hydrophilic areas can be generated on the paper-based devices,
however, the uniformity of pattern on paper was difficult to observe.
For gloss spray lacquer, the results indicated that the hydrophobic
and hydrophilic areas were clearly distinguished (Fig. 3c). Therefore,
the gloss spray lacquer was chosen for fabricating the paper-based
devices throughout the following work.