There are limitations associated with CP like PANi in the context of in vivo applications.

Issues like lower stability with conjugated particles, low mechanical strength, and low

sensitivity are often encountered. These problems are generally addressed by either

chemical modifications on the surface of PANi or mixing/blending with biocompatible

non-conductive polymers with enhanced mechanical strength.

Performance tuned stretchable biocomposites of PPy were used as a potential candidate

for wearable electronics mimicking the skin-like properties. Apart from that, there are

several reports where significant electronic modifications were observed after PPy in­

corporation into the substrate. Out of many, sensors and actuators made of PPy are

trending among the research community with a flexible feature. The capability of PEE-

PPy matrix to convert chemical gradient to mechanical work was demonstrated and it

finds applications in sensors, switches, and ultra-low-power sources. A mechanical sensor

based on PPy-SA-gelatin biocomposite was also developed. Apart from self-healing and

biocompatibility, PPy incorporated sensors presented good flexibility and adjustable re­

sistance under the bending motion of fingers. Flexible supercapacitor electrodes are one

of the essential components of energy storage systems. In this regard, flexible PPy/copper

sulfide (CuS) or bacterial cellulose (BC) nanofibrous composite membranes as super­

capacitor electrodes were proposed [43]. The supercapacitors achieved a relatively high

specific capacitance and retained their initial value even after 300 cycles. PPy and agarose

composite (APY gel) electrodes were prepared for electronic skin mimicking [44]. The

electrodes exhibited Young’s modulus close to human skin and can be directly painted on

human skin for possible bendable or stretchable electronics. Moreover, it showed prop­

erties such as thermoplasticity and self-healing. Another application, which demands

precise and controllable flexibility is actuated catheter. In this perspective, PPy coated

minimally invasive catheter was developed to enhance intravascular navigation during

angiographic procedures [44]. A PA is insoluble, making it very much difficult to process

it for biomedical applications and surface modifications. Since any kind of chemical

modifications in the polymer leads to change in their electronic or mechanical properties,

it hereby hinders any possible chances for PAs to bind any biological molecule.

Nanostructured PEDOT provides an adaptable neural interface coating with minimal

hardness mismatch and glial reaction, improved neural electrode performance by in­

creasing its charge storage ability, and reduced its electrical impedance without a sub­

stantial increase in the geometric surface area [6]. Parylene-based, flexible, neural PEDOT

coated microelectrodes have been successfully used for electrocorticography in rat

brain [45]. Khodagoly and his coworkers developed ‘Neurogrid’, a flexible, ultra-

comfortable high density, low impedance PEDOT coated multielectrode array that was

able to record spikes from individual superficial cortical neurons for one week, without

any intervention [11]. As shown in Figure 23.6, the well-explored CP has established

various applications and with more novel challenges can exile with enhanced properties.

Piezoelectric sensors based on a PVDF nanofibrous membrane and microporous

zirconium-based metal-organic frameworks (MOFs) have been used for arterial pulse

monitoring with superior flexibility over the existing wrist pulse monitoring sensors

(600 mV, 5N) (Figure 23.7i) [47]. Polydopamine (PDA)-barium titanate-polyvinylidene

fluoride (BTO/PVDF) piezoelectric nanocomposites in a fiber made through compre­

hensive phase-field simulation given maximum piezoelectric charge, voltage coefficient,

and mechanical stiffness. The prepared, nonwoven piezoelectric (PMNP) textile showed

outstanding sensitivity and long-term stability for wearable biomonitoring, including

limb motion detection, facial expression identification, respiratory monitoring, and

human-machine interfacing (Figure 23.7ii) [48]. PVDF-TrFE matrix (tuned up to −76.8 mV

Conducting Polymer-Based Biocomposites

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