23.2.4 PA

PA, previously known as polyene, was synthesized by polymerization of acetylene and was

reported by Natta et al. through a noble lecture in 1963 [9]. Shirakawa et al., in their noble

lecture, mentioned that the discovery of the PA film was a fortuitous error and possess

intrinsic electrical properties, which didn’t vary between its powder and film form [10].

Later, due to carbocation of PA, the charge carrier was termed a conducting polymer.

Synthesis of PA is mainly being carried out by three processes: a) catalytic polymerization,

b) non-catalytic polymerization, and c) precursor assisted synthesis. Ziegler–Natta catalysts

offer a good choice for catalytic polymerization owing to good solubility in organic

solvents. For a high molecular weight PA, a luttinger catalyst is used, which utilizes acet­

onitrile and other hydrophilic solvents. Further, non-catalytic polymerization of the PA

includes electrochemical polymerization, where aniline monomers are deposited on the

metallic electrode to get a uniform PA film. Ring-opening polymerization is another

method of synthesis, which doesn’t require any catalyst and electro-machine setup.

23.2.5 PEDOT

PEDOT is a popular member of this group and the very first material used as an electrode on

the human brain [11]. The PEDOT properties depend on the chemical structure, fabrication

condition, incorporation of surfactants or doping, polymer composition, post-treatment, and

polymerization. PEDOT is both n- and p-dopable and also displays electronic, electrical,

and magnetic properties akin to metals and semiconductors. To develop PEDOT with me­

chanical stability, conductivity, and degradation under a change in temperature, pressure, or

time strategies of both fundamental and practical are ensured according to the application.

PEDOT itself and its derivatives are highly transparent in the visible range therefore suitable

as flexible transparent electrodes.

23.2.6 PVDF

PVDF is a widely explored piezoelectric, thermo-mechanically stable, organic polymer for

bioelectronic applications because of its flexible electroactive and processing properties.

It exists in three dominant polymorphic forms, α, β, and γ. Among the three phases, the

β-phase is for the most part electroactive because of the all-trans (TTTT) configuration and

high dipole moment induced from CH2-CF2 [12]. The copolymerization of vinyl di­

fluoride with trifluoroethylene (PVDF-TrFE) also enhances the piezoelectric response

inducing chain alignment and high crystallinity [13].

23.3 Flexible Bioelectronics Synthesis, Fabrication, and Structural Design

PTh: Samanta et al. doped PTh with poly(ethylene glycol) (PEG)2000 and sodium p-toluene

with synthesized PTh-g-poly (dimethylamino ethylmethacrylate) using atom transfer ra­

dical polymerization (ATRP) technique. The graft copolymer using methylcellulose gel was

investigated the result showed photoluminescence property with change in temperature

and pH. The graft copolymer showed similarity to AND logic gate functions, whereas the

change in polarity in hydrogel at microenvironment was altered by the temperature and

pH, which acted as an input, therefore resulting in fluorescent output [14]. The conductive

Conducting Polymer-Based Biocomposites

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