Bio-inspired Polymer Composite Actuator and Generator Driven by Water Gradients
By Mingming Ma, Liang Guo, Daniel G. Anderson, Robert Langer. Science, 2013
756 citations recorded by the source corpus.
Mini Mighty Muscle Actuators—or artificial muscles—take electrical or chemical energy and convert it into mechanical force. Typically, actuators made from polymers can show large deformations, but cannot generate a lot of force. Ma et al. (p. 186; see the Perspective by Kim and Kwon) describe a polymer composite based on a modified polypyrrole that expands in response to water absorption. The composite was able to generate large stresses and forces, and offered a high work density approaching those of the best conducting polymer electrochemical actuators. Magnetic nanoparticles incorporated into polymer films were used to control the locomotion of the actuator. Polymer actuators are manipulated by changing hydration conditions and show strong contractile forces. [Also see Perspective by Kim and Kwon] Here we describe the development of a water-responsive polymer film. Combining both a rigid matrix (polypyrrole) and a dynamic network (polyol-borate), strong and flexible polymer films were developed that can exchange water with the environment to induce film expansion and contraction, resulting in rapid and continuous locomotion. The film actuator can generate contractile stress up to 27 megapascals, lift objects 380 times heavier than itself, and transport cargo 10 times heavier than itself. We have assembled a generator by associating this actuator with a piezoelectric element. Driven by water gradients, this generator outputs alternating electricity at ~0.3 hertz, with a peak voltage of ~1.0 volt. The electrical energy is stored in capacitors that could power micro- and nanoelectronic devices.
Subfields: Biomedical Engineering
View Paper: https://www.semanticscholar.org/paper/3faa75627bc026868b5eec900ac4d31050da080d
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In Biomedical Engineering
Citations in the corpus
- Synthesis, properties, and applications of graphene oxide/reduced graphene oxide and their nanocomposites (2019, background): “For suf fi ciently thick hydrophilic fi lms exposed to water, there results an asymmetric swelling causing bending of fi lms that results in reversible actuation of polymer fi lms upon hydration/dehydration cycling [115 – 117].”
- Hygrobot: A self-locomotive ratcheted actuator powered by environmental humidity (2018, methodology): “The irregular directions of bending and twisting of previous hygroscopic actuators make it nearly impossible to control their wriggling trajectory, severely limiting their use as a robotic actuator (20, 21).”