Light-driven artificial muscles based on electrospun microfiber yarns

Biomimetic Hierarchically Arranged Nanofibrous Structures Resembling the Architecture and the Passive Mechanical Properties of Skeletal Muscles: A Step Forward Toward Artificial Muscle

“…Regarding potential soft robotics applications, several studies have investigated the combination of polyurethane coated with conjugated polymers such as polyaniline ( Kang Gu et al, 2009 ), polypirrole Ebadi et al (2019a , b) and PEDOT ( Kwon et al, 2013 ), showing a good match between an electrostrictive and an elastomeric element. Polyurethane has been also used in blend with cellulose ( Wang et al, 2018 ) or CNTs ( Meng et al, 2019 ) in order to be actuated by moisture or electrical stimuli, respectively. Considering this literature background, in future works we will investigate the possibilities for our PU HNES to reproduce a new generation of bioinspired artificial muscles.…”

“…Increasing the structures complexity, Kang Gu et al (2009) proposed an artificial myofiber made of parallelly arranged PU nanofibers grouped together in a bundle, coated with polyaniline (PANi). More recently, Meng et al (2019) developed a yarn actuator by electrospinning a blend of aligned PU nanofibers loaded with carbon nanotubes (CNTs).…”

Smart Actuators Based on External Stimulus Response

“…Based on the characteristics of a fiber structure mimicking human muscles, CNTs were mixed with PU solution to form electrospinning precursor, and the so-made yarns can be triggered by NIR ( Meng et al, 2019 ). Due to the high heat absorption property of CNTs, CNTs can enable the yarns to efficiently absorb NIR and radiate heat, which induces the fast temperature change that leads to the contraction/expansion motions along the axial direction.…”

A Hollow Polyethylene Fiber-Based Artificial Muscle

“…To date, novel materials with various attributes have been explored and investigated based on different driving mechanisms or stimulus sources to fabricate fiber-shaped actuators acting as artificial muscle. Even though significant progresses on artificial muscle, such as liquid crystal elastomer fibers [14], thermally set silk fibers [10], graphenebased composite fibers [16][17][18], electrospun microfiber yarns [19], coiled polymer (polyethylene or nylon) fibers [20][21][22][23], torsional or twisted carbon nanotube hybrid fibers [3,7,24], have been reported recently and provided people more understanding on this hot research topic. For the strict standards of artificial muscle applications, such as high sensitivity, environmental adaptability, control convenience, and large-scale preparation, these fiber-shaped actuators are still hard to meet the demanding.…”

“…The reported silk-based and graphene oxide-based fiber actuators, acting as a humidity sensitive actuator, are difficult to adapt to easy changing environments [10,16]. The actuation of electrospun microfiber yarn and polymer (polyethylene or nylon) fiber actuators are benefited from their coiled structure, which the structure limited their application at the same time because they always need an extra force to maintain their coiled state [19,20,22]. The actuation behavior of the torsional or twisted carbon nanotube-based artificial muscle could be initiated by multiple stimulation (heat, electricity and vapors) [3,7,24].…”