Conjugated Polymer Actuators and Devices: Progress and Opportunities

Abstract

Conjugated polymers (CP), as exemplified by polypyrrole (PPy), are intrinsically conducting polymers with potential for development as soft actuators or 'artificial muscles' for numerous applications. Significant progress has been made in our understanding of these materials and the actuation mechanisms, aided by the development of physical and electrochemical models. Current research is focused on developing applications utilizing the advantages that CP actuators have (e.g. low driving potential, easy to miniaturise) over other actuating materials and on developing ways of overcoming their inherent limitations. CP actuators are available as films, filaments/yarns and textiles, operating in liquids as well as in air for, ready for use by engineers. This review initially highlights the milestones made in understanding these unique materials and their development as actuators. The primary focus is on the recent progress, developments, applications, and future opportunities for improvement and exploitation of these materials possessing a wealth of multifunctional properties.Received: ((will be filled in by the editorial staff))Revised: ((will be filled in by the editorial staff))

PEDOT-Based Conducting Polymer Actuators

“…EAPs are the current promising artificial biological muscles, owing to their high resilience and fracture toughness, ability to engender large actuation strains, and inherent vibration-damping properties, which are referred to as artificial muscles in many reports (Bar-Cohen, 2000Asplund et al, 2010). According to the deformation mechanism, EAPs can be divided into two categories (Smela, 2003;Romasanta et al, 2015;Kongahage and Foroughi, 2019;Melling et al, 2019). One is the electric field active material (also known as electronic EAPs), which is driven by electric fields or electrostatic action (Coulomb force) in dry environments.…”

“…One is the electric field active material (also known as electronic EAPs), which is driven by electric fields or electrostatic action (Coulomb force) in dry environments. Their actuation typically requires high voltage (about 20 V µm −1 ) (Melling et al, 2019) and specialized electronic equipment, which limits certain applications. The other current-active material is ionic EAPs driven by the mobility or diffusion of ions in solution or air environment.…”

“…Moreover, the more unique properties of CPs, such as holding strain under DC voltage or at open circuit, make it easy to produce consistent material and miniaturization. All these advantages make them promising materials for soft actuators (Melling et al, 2019).…”

Enhancing the Conductivity of the Poly(3,4‐ethylenedioxythiophene)‐Poly(styrenesulfonate) Coating and Its Effect on the Performance of Yarn Actuators

“…Conducting polymers (CPs) are electroactive polymers that deform under an electrical stimulation due to a reversible electrochemical reaction changing material composition and properties (such as volume) . These polymers have been used as soft actuators and often called artificial muscles due to their functional similarity with natural muscles …”

Electrically Pore‐Size‐Tunable Polypyrrole Membrane for Antifouling and Selective Separation

“…Conversely, the ions in the PPy membrane are deintercalated from the PPy at the oxidation potential and enter the bulk solution, resulting in volume shrinkage . Therefore, PPy can be utilized in applications such as electric trigger actuators, drug release, artificial muscles, and energy storage . Otero and Cortés produced all‐polymeric triple‐layer artificial muscles that functioned by swelling and shrinking of PPy in a redox reaction .…”