Fig. 4: 3D-printable conductive PEDOT:AlgS inks for wearable sensing.
a Formulation and crosslinking scheme of conductive inks comprised of alginate with PEDOT fillers doped with AlgS and PSS. b Dispersibility limit of PEDOT:AlgS and PEDOT:PSS in 3% w/v alginate solutions in water. c The relative increase in conductivity of alginate (7.1 × 10−4 S m−1) as a result of introducing conductive PEDOT fillers at their dispersibility limit before crosslinking with Fe3+. The p-value is determined from a two-tailed Student’s t-test with unequal variances (n = 3 independent samples). d Effect of PEDOT dopants on the impedance spectroscopy characteristics of alginate inks. The inset shows Nyquist plots corresponding to the ink formulations. e Illustration of the multilayer patterns of PEDOT:AlgS in alginate after crosslinking in 25 mM FeCl3 solutions. f SEM images of the freeze-dried hydrogels based on the mixtures of PEDOT:PSS and PEDOT:AlgS (4 and 20% w/v, respectively) in alginate (n = 3 independent samples with similar results). g Temperature sensitivity of PEDOT-incorporated alginate hydrogels (n = 3 independent samples). h, i Results of electrocardiogram (ECG) and electromyography (EMG) recordings using conductive hydrogels as electrode interfaces, respectively. Values in (c) and (g) represent the mean and the standard deviation (n = 3 independent samples).
