Fig. 5
Tuning the performances of origami hierarchical sensor array (OHSA). a Schematic illustration of the typical chemical reactions of polydopamine with thiol-containing compounds (via Michael addition) and amino-containing compounds (Schiff base reaction/Michael addition). b Structural formula of the chemical ligands used for the functionalization of P/G ink. Bars (c) and color maps (d) represent the (Rend − Rb)/Rb responses of one-sided OHSA written with different functional P/G inks in different orders toward air exposure, respectively. Data are presented as the mean ± SD. e Microscopic measurement of papers of different thickness (thin, middle and thick). f Plots represent the (Rend − Rb)/Rb responses of one-sided OHSA by using these papers in diverse tracks toward air exposure. Data are presented as the mean ± SD
