Photomodulated Tricolor-Changing Artificial Flowers

Abstract

In nature, many flowers can open their petals into blooming flowers or furl them into buds and simultaneously alter the petal colors under the precise control of light, temperature, pH, humidity, or other environmental stimuli. Inspired by this fascinating natural phenomenon, here we report a two-spiropyran-unit-functionalized, monodomain/polydomain bilayer-structured liquid crystal elastomer strategy to fabricate an ultraviolet, green, and near-infrared trilight-modulated tricolor-changing flower mimic soft actuator. Relying on a combination of photochromic effect, thermochromic effect, pigment blending effect, photothermal conversion effect, and gradient stress effect, this flower mimic material can furl or open it “petals” under the on/off stimulation of near-infrared light and meanwhile possess a tristable showy color switch system which is tunable through varying the wavelength band (365, 520, and 808 nm) of light stimuli. Such a material has wide application prospects in camouflage materials, control devices, and biomimetic devices.

Kirigami‐Based Light‐Induced Shape‐Morphing and Locomotion

“…[17,18] Their versatile deformabilities upon heat/light stimuli give rise to a fast-increasing interest in realization of novel soft robotic systems, in which the nature-inspired strategies are often adopted. Strips mimicking opening and closing of seedpods and flowers, [19,20] actuators exhibiting caterpillar-like motion such as rolling, [21] inching [22] and travelling-wave movement, [23] swimmers mimicking microzooplankton, [24] and snail-like crawlers [25] are but few examples. Due to restrictions in sample size (below few centimeters) and lack of actuation complexity, such soft actuators are based on simple architectures with limited degrees of freedom in movement.…”

Graphene‐Based Bimorph Actuators with Dual‐Response and Large‐Deformation by a Simple Method

“…Flowers are very common in nature and can open their petals into blooming flowers. The pioneering works have shown the fabrication of artificial flower actuators based on silver nanowires/polymer or bilayer liquid crystal elastomer which show electrical voltage or light induced blooming . Here, we further develop artificial flowers with dual responsiveness.…”

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

“…By depending on the structures and compositions, LCE materials can experience shape changes in response to specific external stimuli including magnetism [7,8], heat [9], electric field [10], light [11], ions [12], moisture [13,14], and solvent [15], etc. The outstanding stimuliresponsitivities enable them to be widely used in smart actuators [16][17][18][19][20][21], biomimetic devices [22][23][24][25], artificial organs [26][27][28], and microrobots [29][30][31], etc. Thermal stimuli and light stimuli play major roles in various applications of LCE materials [4,11].…”

“…To overcome this problem, Marshall and Terentjev first utilized light-absorbing organic dyes as the components of photothermal conversion to realize the photo-actuation of LCE materials for reason that they could be dispersed into LCE matrices in molecular sizes [52]. From then on, many near-infrared (NIR) responsive dye-doped LCE materials have been developed [25,40,[53][54][55][56][57][58]. Quasi-daylight sources, with the emission spectra being similar to nature sun-light, generally possess the advantages of economy, convenience, and health, thus it would be more valuable to effectively utilize the energy of quasi-daylight, even the nature sunlight, to drive the actuation of LCE materials.…”

“…The dye-doped LCE materials are conventionally prepared via in situ synthesis by adding the dye molecules into synthetic reaction mixtures [25,40,52,54,55,57]. But the dye molecules may influence the synthesis reactions, while the phase separation may be induced by the synthesis reactions, resulting in the aggregation of dye molecules [59].…”