system was generated, which, when maintained in a well-spaced network, maintained its
connectivity even after the hydrophilic PSS domains have been rehydrated. The amount of
DMSO used in these gels, as well as the duration of the dry annealing process, may be
varied to get the mechanical properties that are needed (Figure 1.6c). It is important to note
that this technology is compatible with inkjet printing and allows for the fabrication of
patterns in a short amount of time (Figure 1.6d).
A combination of PEDOT-PSS and polyethylenimine (PEI) was developed by Cea et al.
[47] to produce a biocompatible material. The active channel of this novel material is
composed mostly of PEDOT-PSS, PEI, and D-sorbitol. In this study, D-sorbitol was uti
lized as a biocompatible stabilizer to boost the hydration and mobility of ions. However,
the interaction between PEDOT-PSS and PEI resulted in the development of unique
electrical characteristics (Figure 1.7a). PEI was responsible for electron transfer and re
duction of PEDOT through the creation of PEI-PSS complexes. It also causes de-doping in
PEDOT, which results in a decrease in its conductivity. When a gate bias is applied, PEI
becomes protonated and releases PSS, which, when bound to PEDOT, restores con
ductivity in the device under consideration. “Channel” is a term that refers to the passage
of information through a channel. The resultant material is extremely stable, and the
redox reaction is nearly perfect in terms of reversibility. The materials discovered may
be easily produced using a typical lithographic technique to generate thin and flexible
FIGURE 1.6
Schematic representation of (a) PEDOT: PSS domain aggregation via water evaporation, (b) morphology for
fibril domain in PEDOT: PSS hydrogel with DMSO as a de-hydrating agent, (c) the curves for Young’s moduli
and ultimate tensile strains in PEDOT: PSS, and (d) the representation of PEDOT: PSS with a free-standing
pattern. Reproduced with permission [ 46]. Copyright (2019), Springer Nature.
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Bioelectronics