Micron‐Scale Soft Actuators Fabricated from Multi‐Shell Polystyrene Particle‐Gold Nanoparticle Nanohybrids

Abstract

Actuators made of soft matter are needed for a variety of fields ranging from biomedical devices to soft robotics to microelectromechanical systems. While there are a variety of excellent methods of soft actuation known, the field is still an area of intense research activity as new niches and needs emerge with new technology development. Here, a soft actuation system is described, based on a core-multi-shell particle, which moves via photothermal expansion. The system consists of a novel polystyrene-based thermally expandable microsphere, with a secondary shell of a silicate-silane graft copolymer, to which gold nanoparticles are covalently linked. The gold nanoparticles act as photothermal nano-transducers, converting light energy into the thermal energy necessary for microsphere expansion, which in turn results in material movement. Actuation is shown in isolated particles in thermal and photothermal regimes using metal ceramic heaters or 520 nm laser illumination, respectively. Macroscale actuation is demonstrated by making a composite material of particles suspended in the transparent elastomer polydimethylsiloxane. The sample demonstrates an inchworm-like movement by starting from an arched geometry. Overall, this work describes a new particle-based actuation method for soft materials, and demonstrates its utility in driving the movement of a composite elastomer.

Self‐healing polymers for soft actuators and robots

“…[41][42][43][44][45][46] The photochemical changes at the molecular scale could transformed into the visible macroscopic deformation of bulk materials, producing the photochemical actuators. On the other hand, introducing the appropriate photothermal constituents into thermalsensitive soft materials, such as metal nanoparticles and derivant, carboneous nanomaterials, organic dyes including cyanines, croconaines, dopamine, porphyrins et al, [47][48][49][50][51][52] could realize various photothermal effects to trigger expansion of volume, phase transitions, desorption of molecules, and surface tension of the matrixes, from which photothermal actuators are fabricated. For photothermal actuators, it's required to design responsive composites with high light absorption and good thermal conductivity so that the photon energy can be effectively converted into heat energy to induce the mechanical deformation.…”

A Data‐Driven Review of Soft Robotics

“…[483,[572][573][574][575] This use case is the only deviation from electric sensors. Chromatically changing actuators, [503] microsphere expansion inducing volumetric changes, [576] and a self-oscillating locomotor are examples of the subjects of just a few of the recent publications that describe optically driven soft devices. [577] The last function medium regards chemical operation.…”

Fast Responsive and High-Strain Electro-Ionic Soft Actuator Based on the 3D-Structure MXene-EGaIn/MXene Bilayer Composite Electrode

“…Soft actuators that can reversibly change their geometric shape, volume, size, or properties under various external stimuli have broad potential in many fields, including soft robots, wearable electronic devices, flexible sensors, energy harvesting, biomedical devices, and artificial intelligence. − Among these, soft actuators stimulated by factors such as light, , electricity, , temperature, , humidity, , and electro-ionic soft actuators exhibit activation and controllable actuation performance at low voltages. In recent years, electro-ionic soft actuators have attracted wide attention due to their lightweight, high flexibility, and simple manufacturing process.…”