Photothermal Thin Films with Highly Efficient NIR Conversion for Miniaturized Liquid-Crystal Elastomer Actuators

Abstract

This work presents the development of highly efficient photothermal thin films (PTFs) and the demonstration of their application on miniaturized polymer-based soft actuators. The proposed PTF, which comprises acrylic-based black paint and EGaIn liquid metal (LM) microdroplets, serves as an excellent absorber for efficiently converting near-infrared (NIR) irradiation into heat for actuating liquid-crystal elastomer (LCE) actuators. The introduction of LM microdroplets into the PTFs effectively increases the overall thermal efficiency of PTFs. Miniaturized soft crawlers monolithically integrated with the NIR-driven LCE actuators are also implemented for demonstrating the application of the proposed PTF. The crawler’s locomotion, which is inspired by the rectilinear movement of snakes, is generated with the proposed PTF for inducing the LC-to-isotropic phase transition of the LCEs. The experimental results show that introducing LM microdroplets into the PTF can effectively reduce the thermal time constants of LCE actuators by 70%. Under periodic on/off NIR illumination cycles, the locomotion of crawlers with different dimensions is also demonstrated. The measurement results indicate that the proposed PTF is not only essential for enabling photothermal LCE actuation but also quite efficient and durable for repeated operation.

Innovations in spider silk‐inspired artificial gel fibers: Methods, properties, strengthening, functionality, and challenges

“…In recent times, the integration of physics and chemistry has enabled the miniaturization of actuators at micro and nanoscales, which are vital for several applications such as soft robotic systems and drug delivery. Various materials with special stimulus‐responsive properties have been developed into actuators, including dielectric‐, LCE, gels, conductive polymers, shape memory polymers, and carbon nanomaterials, into various configurations such as fibers, films, and bulky objects (3D) 252 . In addition, LCE fibers, in particular, with good shape deformability and reversibility, are ideal choice for soft actuators 253 .…”

Electrically Driven Crosslinked Liquid Crystal Polymers†

“…Thus, incorporating LM into LCE can enhance the thermal conductivity of the material while preserving its flexibility and shape‐change capabilities. [ 21,72‐75 ] Additionally, owing to LM's superior fluidity of LMs compared with that of solid metals, they can be patterned and processed as desired. [ 76 ]…”

“…This two‐way shape‐memory behavior enables CLCP to achieve various motion modes and hold significant potential in various fields, including artificial muscles, bionic actuators, and soft robots, which can further advance the human society. [ 18‐29 ]…”

Plasmonic group IV transition metal carbide interfaces for solar-driven desalination

“…16 To tackle these efficiency issues an influx of research has gone into discovering materials which can absorb broadband solar radiation and harness it to generate heat for water evaporation. Known as photothermal materials, the most prominent examples include non-radiative recombination in inorganic semiconductors, [17][18][19][20] thermal vibration in polymeric materials [21][22][23] and carbon-based light absorbers, [24][25][26][27][28][29] and localized heating in plasmonic nanostructures. 30,31 Plasmonic materials are perhaps the most promising as they display efficient light-to-heat conversion.…”