Photo-Actuation of Liquid Crystalline Elastomer Materials Doped with Visible Absorber Dyes under Quasi-Daylight

Abstract

We studied the effect of visible absorber dyes on the photo-actuation performances of liquid crystalline elastomer (LCE) materials under quasi-daylight irradiation. The dye-doped LCE materials were prepared through infiltrating visible absorber dyes into a polysiloxane-based LCE matrix based on its solvent-swollen characteristic. They demonstrated well absorption properties in visible spectrum range and performed strong actuation upon the irradiation from quasi-daylight source, thus indicating that the presence of visible absorber dyes effectively sensitized the LCE materials to light irradiation since the light energy was absorbed by the dyes and then converted into heat to trigger the phase change of LCE matrix. The photo-actuation properties of dye-doped LCE materials with different visible absorber dyes, varied dye contents, and irradiation intensities were investigated. It was shown that the visible absorber dyes with different absorption bands created different photo-actuation performances of LCE materials, the one whose absorption band is near the intensity peak position of quasi-daylight spectrum created the optimum photo-actuation performance. The result disclosed a valuable light utilization way for photo-controlled LCE materials since it revealed that a light-absorbing dye, whose absorption band is in the high intensity region of light spectrum, is capable of effectively utilizing light energy to drive the actuation of LCE materials.

Liquid crystal-based actuators

“…Light can be employed to heat LCN if one introduces photothermal agents into the material (Dong and Zhao, 2018), which can convert light energy to thermal energy. Graphenes (Wei et al, 2016), carbon nanotubes (CNTs) (Ji et al, 2010;Camargo et al, 2011), metal nanoparticles (Sun et al, 2012;Hauser et al, 2016), dyes (de Haan et al, 2012Guo et al, 2016;Gelebart et al, 2017;Qin et al, 2020), and conjugated polymers (Liu et al, 2016) often serve as dopants due to their high light absorption and quantum yield of photo-thermal energy conversion for certain wavelengths (Dong and Zhao, 2018). Graphenes, CNTs, and metal nanoparticles are efficient at absorbing both visible (VIS) and near-infrared (NIR) light, while dyes are more specific (for instance, Lumogen IR788 (de Haan et al, 2012) and Dye 1002 (Kohlmeyer and Chen, 2013) are for NIR light; ABS407, ABS594, and ABS694 dyes (Qin et al, 2020) are for VIS light).…”

Toward Application of Liquid Crystalline Elastomer for Smart Robotics: State of the Art and Challenges

“…Thermally actuated LCEs can be easily converted into light-driven actuators by using photothermal effects ( Figure 4 d). Many photothermal fillers, such as carbon nanotubes (CNTs) [ 70 , 117 , 118 , 119 , 120 , 121 , 122 ], graphene oxides [ 123 ], dyes [ 29 , 122 , 124 , 125 , 126 , 127 , 128 , 129 ], gold nanorods [ 130 , 131 ], nanoparticles [ 132 ], conjugated polymers [ 133 ], and polydopamine [ 134 , 135 ], have been successfully introduced into LCEs to enable their light responsiveness. Kim et al [ 86 ] presented a strategy for preparing programmable, multiresponse LCE/CNT composites that can respond to both optical ( Figure 4 f) and electrical stimuli by introducing CNT functional fillers into LCE matrix.…”

Varied Alignment Methods and Versatile Actuations for Liquid Crystal Elastomers: A Review

“…Through material and structural designs and innovations in actuation technologies, it is expected to achieve more versatile deformation actuations for LCEs. 1) Material and structural designs: Through integrating heterogeneous materials and structures with different properties at multiple spatial scales, the mechanical properties [87,117,119,120] and stimuliresponsive performances [2,11,[121][122][123][124][125] of LCE composites can be tuned to a large extent, so as to enrich the deformation modes of LCEs. The common multiscale integration designs include adding nanoparticles (nanoscale), designing interpenetrating polymer networks or phase separation structure (mesoscale), patterning integration for multimaterials by 4D printing (microscale), and intralayer or interlayer bonding of multimaterials (macroscale).…”