Figure 4 | Scientific Reports

Figure 4

From: The pursuit of further miniaturization of screen printed micro paper-based analytical devices utilizing controlled penetration towards optimized channel patterning

Figure 4

View of front and back face (shown on the left and right side of each pair of channels, respectively) of the paper substrates after being patterned. Colored-ink water was flown through the channels, and the background of the images was removed through image processing for clearer visualization. For the case of Xuan paper, all the patterns were found to be the same on the front and back face of the substrate, after the hydrophobic agent was squeegeed one time, implying that the barrier penetrated completely through the thickness of the substrate. Whatman filter paper, however, presented considerable leakage of the flow on the back face of the substrate, indicating that one squeeze of the hydrophobic agent is not enough to build an effective barrier.

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