Segmented Polyurethane Elastomers with Mechanochromic and Self‐Strengthening Functions

Seshimo, Kota; Sakai, Hio; Watabe, Takuma; Aoki, Daisuke; Sugita, Haruo; Mikami, K.; Mao, Yuchen; Ishigami, Akira; Nishitsuji, Shotaro; Kurose, Takashi; Ito, Hiroshi; Otsuka, Hideyuki

doi:10.1002/anie.202015196

Cited by 85 publications

(71 citation statements)

References 40 publications

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“…The radicals generated from dissociated DFSN under mechanical stimuli have also been shown to be capable of initiating radical polymerization. [ 201 ] The Otsuka group designed a segmented PU with DFSN located in the soft segment and methacryloyl groups in the side chains (Figure 25C). When external force was applied, the DFSN in the PU sample dissociated into pink radicals.…”

Section: Applicationsmentioning

confidence: 99%

Mechanochromophore‐Linked Polymeric Materials with Visible Color Changes

Qiu

Scofield

Gurr

et al. 2022

Macromol. Rapid Commun.

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Mechanical force as a type of stimuli for smart materials has obtained much attention in the past decade. Color‐changing materials in response to mechanical stimuli have shown great potential in the applications such as sensors and displays. Mechanochromophore‐linked polymeric materials, which are a growing sub‐class of these materials, are discussed in detail in this review. Two main types of mechanochromophores which exhibit visible color change, summarized herein, involve either isomerization or radical generation mechanisms. This review focuses on their synthesis and incorporation into polymer matrices, the type of mechanical force used, factors affecting the mechanochromic properties, and their applications.

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Section: Applicationsmentioning

confidence: 99%

Mechanochromophore‐Linked Polymeric Materials with Visible Color Changes

Qiu

Scofield

Gurr

et al. 2022

Macromol. Rapid Commun.

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“…52,53 However, as previously discussed, a few covalent systems have been shown to be reversible. Diarylbibenzofuranones [24][25][26] and difluorenylsuccinonitriles 27 are relevant conceptual examples to compare with Tr, since they are both scissile designs. The recombination process is not entropically favored with these motifs, thus the thermodynamic and kinetic stability of the mechanically activated species is paramount to avoid their decomposition or the incursion of parallel reactions involving them.…”

Section: The Potential Reversibility Of Triarylmethane Mechanophoresmentioning

confidence: 99%

A Perspective on the Force-Induced Heterolytic Bond Cleavage in Triarylmethane Mechanophores

Berrocal

Hemmer

2022

Synlett

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Triarylmethane derivatives and their corresponding trityl carbocations are among the oldest chemical species synthesized and studied by chemists. The carbocationic platforms are particularly interesting due to their stability, high extinction coefficient, and tunable absorption of light in the visible spectrum, which can be achieved through structural modifications. These stable cations are traditionally obtained through heterolytic cleavage of judiciously designed, parent triarylmethanes by exposure to acids or UV light (λ < 300 nm), and methods based on electrochemistry or radiolysis. Our group has recently discovered that trityl carbocations can be generated also via mechanical stimulation of solid polymer materials featuring triarylmethane units as covalent crosslinks. In this Synpacts contribution, we expand on our previous finding by discussing some intriguing research questions that we aim to tackle in the immediate future. 1 Introduction 2 The development of our first triarylmethane mechanophore 3 The potential reversibility of triarylmethane mechanophores 4 A general molecular platform for force-induced, scissile, homolytic and heterolytic bond cleavage? 5 Conclusion

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“…Innovative applications of SP-based systems include stretchable mechanochromic electronic skins, [161] 3D printed mechanochromic materials, [174] and visual-indicators for safe surgery. [175] Next to SP, other mechanochromic compounds find applications as colorimetric strain sensors, [176,177] touch sensors, [178,179] chromogenic probes in the visible and near-infrared, [159,180,181] and in devices for biological [182] and medical use [183] (Figure 4f). Similarly, mechanoresponsive luminescent materials, thanks to the high susceptibility of fluorescence emission to chemical and environmental variations, often find applications as precise probes for mechanical stress, heat, pH, and electromagnetic radiation.…”

Section: From Cromatophore As Absorbance Elements Through Molecular Mechanochromic Devicesmentioning

confidence: 99%

A Perspective on Cephalopods Mimicry and Bioinspired Technologies toward Proprioceptive Autonomous Soft Robots

Giordano

Carlotti

Mazzolai

2021

Adv Materials Technologies

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scientific community. [1][2][3][4][5][6][7] Regardless, every time a living being reveals novel adaptive and dynamically reactive mimicry behavior, it inspires and fosters futuristic and unexpected technological outcomes. [8][9][10][11][12] At the biological level, the visual crypsis is the ability of a species to resemble the surroundings by matching the coloration and the geometrical patterns of the habitat. In this sense, a living being can control its appearance optically (thanks to arranged and optimized structures at the mesoscopic scale, by means of pigmentation, or emissive elements) and morphologically (it can show wrinkles and textures on the body to evade detection or observation). [13][14][15][16][17][18] Both these mechanisms are characterized by a time response that ranges from milliseconds to hundreds of seconds. In nature, several species take advantage of cryptic abilities, as, e.g., in cephalopods, [7] crustaceans, [19] reptilians, [1,20,21] insects, [22,23] birds, [24,25] shells, [26,27] plants, [28,29] among many. The biotic color changing and body patterning relate to reproductive, communicative, and defensive and/or predatory strategies. Unfortunately, the nervous or central control-chain system that steers these behaviors in animals and plants, is still somehow fogged for scientists. [7,[30][31][32] A complete knowledge about their central information process systems, can open to astonishing developments in many scientific branches, from neurobiology [33,34] to quantum biology. [35] Undoubtedly, the most debated case of study in the natural world are cephalopods, which not only are highly evolved and specialized in fast adaptive color changing displays, but also are able to actuate their skin to generate 3D patterns, when exposed to specific mechanical, thermal, optical, or chemical stimuli. Soft muscular arrangements, [36][37][38] spatially distributed and expandable absorbing components (namely chromatophores), [39,40] iridescent elements (namely irido phores), [41,42] and bright white scatterers (namely leucophores) [43] are responsible for textural, postural and color changing. Moreover, octopuses are a remarkable intelligent species, able, for example, to open a jar or avoid predators in the order of seconds. [44] Thus, cephalopods are usually regarded as a perfect example of embodied intelligence, [45] thanks to the symbiosis between their body's mechanics and morphology, and the distributed sensory neuro-motor-control system. Their "learning", "mechanical" and "material intelligence" will be our lodestars along this review, resulting in a fascinating connection between Octopus skin is an amazing source of inspiration for bioinspired sensors, actuators and control solutions in soft robotics. Soft organic materials, biomacromolecules and protein ingredients in octopus skin combined with a distributed intelligence, result in adaptive displays that can control emerging optical behavior, and 3D surface textures with rough geometries, with a remarkably high control speed (≈ms). To be able ...

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Segmented Polyurethane Elastomers with Mechanochromic and Self‐Strengthening Functions

Cited by 85 publications

References 40 publications

Mechanochromophore‐Linked Polymeric Materials with Visible Color Changes

Mechanochromophore‐Linked Polymeric Materials with Visible Color Changes

A Perspective on the Force-Induced Heterolytic Bond Cleavage in Triarylmethane Mechanophores

A Perspective on Cephalopods Mimicry and Bioinspired Technologies toward Proprioceptive Autonomous Soft Robots

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