Functional devices primarily based on soft materials have many natural examples, but perhaps prime among these: the octopus. This invertebrate can exhibit multiple modes of locomotion, [5,6] macroscale shape, [7] and color changes for communication and camouflage. [8] Several of these features have already been artificially realized, including soft robotic arms capable of elongation, shortening, bending, [7] and crawling, [9] form-fitting to gently pick up delicate bodies, [10] and robots capable of navigating 3D environments through both large voids and confined spaces by changing morphology. [11] Likewise, research into responsive color adaptability has resulted in actuators combining structural and pigmental color changes, [12] poly mer-dispersed systems that can reversibly change color by heating, [8] and 3D printed cholesteric elastomer materials that respond to atmospheric humidity. [13] Normally, the desire for multiple functions in a single printed device is followed by the need for multiple printing feed materials-if not also multiple processing techniques. This makes upscaling and commercialization of such versatile soft robots less attractive. [14] In this work, we present a soft robot fabrication concept using easily-synthesized, azobenzene-functionalized cholesteric liquid crystal ("azo-ChLC") oligomer inks. For processing, we use high-operating temperature direct ink write (DIW) 3D printing, a versatile technique that has shown great promise for printing liquid crystalline materials in recent years. [15] The capability of printing structurally colored cholesteric inks is a rather recent addition, [13,16,17] the possibilities of which we aim to broaden in this paper.During a single direct ink writing print run, the azo-ChLC oligomer ink's constituent molecules can self-organize supramolecularly into three distinct, "macroscopic" mesophase alignments: uniaxial planar pseudo-nematic, typically used for soft actuators, and structurally colored planar and slanted chiral nematics (cholesterics), which can both be used as photonic elements. [15] Incorporating a photoisomerizable azobenzene derivative into a liquid crystal is a common way to achieve photo-actuation, [18,19] and has also been applied successfully in DIW printed LC elastomers since. [20,21] The potential of this single-material, multi-alignment DIW approach is finally demonstrated with structurally colored, lightresponsive actuators. Depositing the ink in specific areas using specific alignments simply by adjusting the local print conditions, these multi-domain "4D" photonic actuators (the "4 th Envisioning robotic devices with functionality resulting from processing rather than exclusively material composition, multimodal responsive devices produced from a single azobenzene-functionalized cholesteric liquid crystal elastomer ink are demonstrated. The resulting device displays simultaneous structural color and actuation in response to both ultraviolet and blue light exposures. Through direct ink writing, a microextrusion-based additive manufa...

As buildings are a large energy user, it is important to not only reduce their consumption, but also have them generate their own electricity. Here, we describe a smart window that could reduce electricity consumption, normally used for air conditioning and lighting, by absorbing excess solar radiation with dichroic fluorescent dye molecules aligned in a switchable liquid crystal host and guiding the re-emitted light energy to the edges of the device, where it can be used to generate electricity via attached photovoltaic cells. The liquid crystals are responsive both to temperature changes and applied electrical fields. At higher temperatures, transmission decreases due to increased disorder in the liquid crystals, while the application of an electrical field increases transmission by effectively realigning the dyes for minimal absorption. Using alternative configurations, a window with a transparent rest state was also produced, in which transmission can be decreased by applying an electrical field; the thermal response remains identical.