Search

It remains a challenge to produce soft robots that can mimic the responsive adaptability of living organisms. Rather than fabricating soft robots from bulk hydrogels,hydrogels are integrated into the interfacial assembly of aqueous two-phase systems to generate ultra-soft and elastic all-aqueous aquabots that exhibit responsive adaptability, that can shrink on demand and have electrically conductive functions. The adaptive functions of the aquabots provide a new platform to develop minimally invasive surgical devices, targeted drug delivery systems, and flexible electronic sensors and actuators.

Smart soft materials are the focus of extensive research efforts due to their potential applications in various fields. Inspired by nature, embedding smart micro‐inclusions in a soft substrate provides a feasible strategy to integrate the smartness of individual microparticles for creating smart materials at the macroscale, broadening the capabilities and applications of smart soft materials. This strategy decouples the design of intelligence and substrate materials, leading to a broader design space for both the smartness and the mechanical properties of the composites. In this Perspective, recent advances in creating smart soft materials using smart microparticles are summarized. The methods developed to construct composites of microparticles in a soft matrix are first introduced, followed by detailed discussions on the material compositions, stimuli and responsiveness, and properties of individual microparticles and the composite systems. Various applications based on advanced functionalities and capabilities that are enabled by those smart soft materials are highlighted. This study also points out research directions to further advance unconventional smart soft materials following this bioinspired approach. [ABSTRACT FROM AUTHOR]

Copyright of Automatisierungstechnik is the property of De Gruyter and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The dynamic nature of calamitic liquid crystals is exploited to perform isothermal phase transitions driven by dynamic covalent chemistry. For this purpose, nematic (N) arrays based on aldehyde 1 were treated with different amines (A–E) in an on‐surface process, which resulted in different isothermal phase transitions. These phase transformations were caused by in situ imination reactions and are dependent on the nature of the added amine. Transitions from the N to crystal (1A, 1E), isotropic (1B), and smectic (Sm) (1C, 1D) phases were achieved, while the resulting materials feature thermotropic liquid crystal behavior. A sequential transformation from the N 1 to the Sm 1C and then to the N 1B was achieved by coupling an imination to a transimination processes and adjusting the temperature. All of these processes were well characterized by microscopic, spectroscopic, and X‐ray techniques, unlocking not only the constitutional but also the structural aspects of the phase transitions. This work provides new insights into designing constitutionally and structurally adaptable liquid crystal systems, paving the way toward the conception of programable evolutive pathways and adaptive materials. [ABSTRACT FROM AUTHOR]

DNA origami nanodevices achieve programmable structure and tunable mechanical and dynamic properties by leveraging the sequence‐specific interactions of nucleic acids. Previous advances have also established DNA origami as a useful building block to make well‐defined micron‐scale structures through hierarchical self‐assembly, but these efforts have largely leveraged the structural features of DNA origami. The tunable dynamic and mechanical properties also provide an opportunity to make assemblies with adaptive structures and properties. Here the integration of DNA origami hinge nanodevices and coiled‐coil peptides are reported into hybrid reconfigurable assemblies. With the same dynamic device and peptide interaction, it is made multiple higher‐order assemblies (i.e., polymorphic assembly) by organizing clusters of peptides into patches or arranging single peptides into patterns on the surfaces of DNA origami to control the relative orientation of devices. The coiled‐coil interactions are used to construct circular and linear assemblies whose structure and mechanical properties can be modulated with DNA‐based reconfiguration. Reconfiguration of linear assemblies leads to micron scale motions and ≈2.5‐10‐fold increase in bending stiffness. The results provide a foundation for stimulus‐responsive hybrid assemblies that can adapt their structure and properties in response to nucleic acid, peptide, protein, or other triggers. [ABSTRACT FROM AUTHOR]

Inspired by nature, self‐regulation can be introduced in synthetic hydrogels by incorporating chemo‐mechanical signals or coupled chemical reactions to maintain or adapt the material's physico‐chemical properties when exposed to external triggers. In this work, we present redox and light dual stimuli responsive hydrogels capable of rapidly adapting the polymer crosslinking network while maintaining hydrogel stability. Upon irradiation with UV light, polymer hydrogels containing redox responsive disulfide crosslinks and light responsive ortho‐nitrobenzyl moieties show a release of payload accompanied by adaptation of the hydrogel network towards higher stiffness due to in situ crosslinking by S‐nitrosylation. Whereas the hydrogel design allows the network to either become softer in presence of reducing agent glutathione or stiffer upon UV irradiation, simultaneous application of both stimuli induces network self‐regulation resulting in a pulsatile form of payload release from the hydrogel. Finally, adaptive stiffness was used to make tunable hydrogels as substrates for different cell lines. [ABSTRACT FROM AUTHOR]

Hydrogels have emerged as prototypical stimuli‐responsive materials with potential applications in soft robotics, microfluidics, tissue engineering, and adaptive optics. To leverage the full potential of these materials, fabrication techniques capable of simultaneous control of microstructure, device architecture, and interfacial stability, that is, adhesion of hydrogel components to support substrates, are needed. A universal strategy for the microfabrication of hydrogel‐based devices with robust substrate adhesion amenable to use in liquid environments would enable numerous applications. This manuscript reports a general approach for the facile production of covalently attached, ordered arrays of microscale hydrogels (microgels) on silicone supports. Specifically, silicone‐based templates are used to: i) drive mechanical assembly of prepolymer droplets into well‐defined geometries and morphologies, and ii) present appropriate conjugation moieties to fix gels in place during photoinitiated crosslinking via a "graft from" polymerization scheme. Automated processing enabled rapid microgel array production for characterization, testing, and application. Furthermore, the stimuli‐responsive microlensing properties of these arrays, via contractile modulated refractive index, are demonstrated. This process is directly applicable to the fabrication of adaptive optofluidic systems and can be further applied to advanced functional systems such as soft actuators and robotics, and 3D cell culture technologies. [ABSTRACT FROM AUTHOR]

[Display omitted] Cephalopods have evolved an all-soft skin that can rapidly display colors for protection, predation, or communication. Development of synthetic analogs to mimic such color-changing abilities in the infrared (IR) region is pivotal to a variety of technologies ranging from soft robotics, flexible displays, dynamic thermoregulatory systems, to adaptive IR disguise platforms. However, the integration of tissue-like mechanical properties and rapid IR modulation ability into smart materials remains challenging. Here, by drawing inspiration from cephalopod skin, we develop an all-soft adaptive IR composite that can dynamically change its IR appearance upon equiaxial stretching. The biomimetic composite is built entirely from soft materials of liquid metal droplets and elastic elastomer, which are analogs of chromatophores and dermal layer of cephalopod skin, respectively. Driven by externally applied strains, the liquid metal inclusions transition between a contracted droplet state with corrugated surface and an expanded platelet state with relatively smooth surface, enabling dynamic variations in the IR reflectance/emissivity of the composite and ultimately resulting in reversible IR adaption. Strain-actuated flexible IR displays and pneumatically-driven soft devices that can dynamically manipulate their IR appearance are demonstrated as examples of the applicability of this material in emerging adaptive soft electronics. [ABSTRACT FROM AUTHOR]

Cellular organisms possess intricate mechano‐adaptive systems that enable them to sense forces and process them with (bio)chemical circuits for functional adaptation. Inspired by such processes, this study introduces a hydrogel system capable of mechanically activated and chemically transduced self‐destruction. Our judiciously designed hydrogels can mechanically generate radicals that are processed and amplified in a self‐propagating radical de‐crosslinking reaction, ultimately leading to mechanically triggered self‐immolation. We put such systems to work in mechano‐induced debonding, and in a bilayer actuator, where swelling‐induced bending generates sufficient force for selective degradation of one layer, leading to autonomous self‐regulation associated with unbending. Our work helps define design criteria for molecularly controlled adaptive and self‐regulating materials with embodied mechano‐chemical information processing, and showcases their potential for adhesives and soft robotics. [ABSTRACT FROM AUTHOR]

Super-resolution fluorescence microscopy techniques are powerful tools to investigate polymer systems. In this review, we address how these techniques have been applied to hydrogel nano- and microparticles, so-called nano- or microgels. We outline which research questions on microgels could be addressed and what new insights could be achieved. Studies of the morphology, shape, and deformation of microgels; their internal compartmentalization; the cross-linker distribution and polarity inside them; and their dynamics and diffusion are summarized. In particular, the abilities to super-resolve structures in three dimensions have boosted the research field and have also allowed researchers to obtain impressive 3D images of deformed microgels. Accessing information beyond 3D localization, such as spectral and lifetime properties and correlative imaging or the combination of data with other methods, shines new light onto polymer systems and helps us understand their complexity in detail. Such future trends and developments are also addressed. [ABSTRACT FROM AUTHOR]

Traditional orthopedic casting strategies used in the treatment of fractured limbs, such as fiberglass and plaster‐based tapes, suffer from several drawbacks, including technically challenging molding for application, occurrence of skin complications, and the requirement of a potentially hazardous oscillatory saw for removal, which is frightening for pediatric patients. This work presents the design and evaluation of a foam‐fabric cast (FFC) to overcome these drawbacks by integrating strategies from soft materials engineering and functional apparel design. A fabric sleeve is designed to enable the reactive injection molding of a polymer foam and provide a form‐fitting orthopedic cast for the human forearm—with sufficient mechanical reinforcement to stabilize a fractured limb. Through testing with a replica limb and human subjects with a range of forearm volumes, the FFC application process is demonstrated and characterized. The thermal, pressural, chemical, and hygienic safety are comparable to or safer than existing clinical technologies. The FFC weighs only ≈150 g, is water resistant, and represents a robust alternative to traditional casts that can be i) manufactured at a large scale for a low cost; ii) applied to patients simply, rapidly (≈5 min), and reliably; and iii) removed easily with a pair of scissors. [ABSTRACT FROM AUTHOR]

Thermal stiffening materials that are naturally soft but adaptively self‐strengthen upon heat are intriguing for load‐bearing and self‐protection applications at elevated temperatures. However, to simultaneously achieve high modulus change amplitude and high mechanical strength at the stiffened state remains challenging. Herein, entropy‐mediated polymer–mineral cluster interactions are exploited to afford thermal stiffening hydrogels with a record‐high storage modulus enhancement of 13 000 times covering a super wide regime from 1.3 kPa to 17 MPa. Such a dramatic thermal stiffening effect is ascribed to the transition from liquid‐liquid to solid–liquid phase separations, and at the molecular level, driven by enhanced polymer–cluster interactions. The hydrogel is further processed into sheath–core fibers and smart fabrics, which demonstrate self‐strengthening and self‐powered sensing properties by co‐weaving another liquid metal fiber as both the joule heater and triboelectric layer. [ABSTRACT FROM AUTHOR]

Natural superorganisms transform their collective shape for benefits, such as the safe transport of objects/themselves, which a sole individual cannot achieve. A significant gap exists between the transformability of natural superorganisms and the artificial emulation thereof. Here, the multi‐transformability and functions of a fire ant superorganism are imitated by a superhydrophobic nano‐magnetite swarm. The synthetic swarm at a liquid−air interface is transformed from a dispersed state into a 2D raft and a 3D bivouac by a magnetic field gradient. The swarm can transport small objects adaptively irrespective of their state (gas/liquid/solid) by switching their state without hindrance from physical obstacles. The swarm also exhibits adaptive jamming transition for regeneration ability, obstacle penetration, and dispersed solids collection. This work contributes to the development of swarm biomimetics, object transportation, and adaptive materials. [ABSTRACT FROM AUTHOR]

Endowing artificial advanced materials and systems with biomimetic self‐regulatory intelligence is of paramount significance for the development of somatosensory soft robotics and adaptive optoelectronics. Herein, a bioinspired phototropic MXene‐reinforced soft tubular actuator is reported that exhibits omnidirectional self‐orienting ability and is capable of quickly sensing, continuously tracking, and adaptively interacting with incident light in all zenithal and azimuthal angles of 3D space. The novelty of the soft tubular actuator lies in three aspects: 1) the new polymerizable MXene nanomonomer shows high compatibility with liquid crystal elastomer (LCE) matrices and can be in situ photopolymerized into the polymer networks, thus enhancing the mechanical and photoactuation properties; 2) the distinct hollow and radially symmetrical structure facilitates the actuator with fast photoresponsiveness and phototropic performance through retarding the heat conduction along the radial direction; 3) the MXene‐LCE soft tubular actuator simultaneously integrates sensing, actuation, and built‐in feedback loop, thus leading to a high light‐tracking accuracy and adaptive phototropism like a hollow stem of plants in nature. As a proof‐of‐concept demonstration, an adaptive photovoltaic system with solar energy harvesting maximization is illustrated. This work can provide insights into the development of artificial intelligent materials toward adaptive optoelectronics, intelligent soft robotics, and beyond. [ABSTRACT FROM AUTHOR]

Superlubricity is a terminology often used to describe a sliding regime in which the adhesion leading to friction or resistance to sliding literally vanishes. For improved energy security, environmental sustainability, and a decarbonized economy, achieving superlubric sliding surfaces in moving mechanical systems sounds very exciting, since friction adversely impacts the efficiency, durability, and environmental compatibility of many moving mechanical systems used in industrial sectors. Accordingly, scientists and engineers have been exploring new ways to achieve macroscale superlubricity through the use of advanced materials, coatings, and lubricants for many years. As a result of such concerted efforts, recent developments indicate that with the use of the right kinds of solids, liquids, and gases on or in the vicinity of sliding contact interfaces, one can indeed achieve friction coefficients well below 0.01. The friction coefficient below this threshold is commonly termed the superlubric sliding regime. Hopefully, these developments will foster further research in the field of superlubricity and will ultimately give rise to the industrial scale realization of nearly-frictionless mechanical systems consuming far less energy and causing much-reduced greenhouse gas emissions. This will ultimately have a substantial positive impact on the realization of economically and environmentally viable industrial practices supporting a decarbonized energy future. In this paper, we will provide an overview of recent progress in superlubricity research involving solid, liquid, and gaseous media and discuss the prospects for achieving superlubricity in engineering applications leading to greater efficiency, durability, environmental quality, and hence global sustainability.

The effect of anisotropic surface roughness on the spontaneous transport of droplets on chemical wettability gradients has not been investigated. Understanding the details of this process has the potential to unlock new fluid handling functionality critical to the development of next‐generation surfaces with intelligent control capabilities. Herein, the fabrication of chemical gradients with mechanically tunable anisotropic microtopography (microwrinkles with directional roughness) is described and the use of these surfaces in programable microdroplet transport is reported. In particular, the interplay between chemical gradient intensity, microwrinkle orientation, and droplet velocity/trajectory was investigated, enabling the rational synthesis of surface fluidic systems capable of mechanically programmable 2D droplet manipulations, vertical droplet transport, and droplet combination. These findings highlight the sophisticated capabilities of mechanically switchable droplet handling systems and demonstrate new avenues for designing intelligent materials with programable transport properties for potential use in surface/microfluidics, water harvesting, energy generation, bioanalysis, and microreactor design. [ABSTRACT FROM AUTHOR]

The effect of anisotropic surface roughness on the spontaneous transport of droplets on chemical wettability gradients has not been investigated. Understanding the details of this process has the potential to unlock new fluid handling functionality critical to the development of next‐generation surfaces with intelligent control capabilities. Herein, the fabrication of chemical gradients with mechanically tunable anisotropic microtopography (microwrinkles with directional roughness) is described and the use of these surfaces in programable microdroplet transport is reported. In particular, the interplay between chemical gradient intensity, microwrinkle orientation, and droplet velocity/trajectory was investigated, enabling the rational synthesis of surface fluidic systems capable of mechanically programmable 2D droplet manipulations, vertical droplet transport, and droplet combination. These findings highlight the sophisticated capabilities of mechanically switchable droplet handling systems and demonstrate new avenues for designing intelligent materials with programable transport properties for potential use in surface/microfluidics, water harvesting, energy generation, bioanalysis, and microreactor design.

Developing gel materials with tunable frictional properties is crucial for applications in soft robotics, anti-fouling, and joint protection. However, achieving reversible switching between extreme sticky and slippery states remains a formidable challenge due to the opposing requirements for energy dissipation on gel surfaces. Herein, a self-adaptive bicontinuous fluorogel is introduced that decouples lubrication and adhesion at varying temperatures. The phase-separated fluorogel comprises a soft fluorinated lubricating phase and a stiff yet thermal-responsive load-bearing phase. At ambient temperature, the fluorogel exhibits a highly slippery surface owing to a low-energy-dissipating lubricating layer, demonstrating an ultralow friction coefficient of 0.004. Upon heating, the fluorogel transitions into a highly dissipating state via hydrogen bond dissociation, concurrently releasing adhesive dangling chains to make the surface highly sticky with an adhesion strength of ≈362 kPa. This approach provides a promising foundation for creating advanced adaptive materials with on-demand self-adhesive and self-lubricating capabilities., (© 2024 Wiley‐VCH GmbH.)

There is growing interest in developing methods to 'wrap' nano‐ and micron‐sized biological objects within films that may offer protection, enhance their stability or improve performance. We describe the successful 'wrapping' of lectin‐decorated microspheres, which serve as appealing model micron‐sized objects, within cross‐linked polymer film. This approach utilizes polymer chains able to undergo a structural metamorphosis, from being intramolecularly cross‐linked to intermolecularly cross‐linked, a process that is triggered by polymer concentration upon the particle surface. Experiments demonstrate that both complementary molecular recognition and the dynamic covalent nature of the crosslinker are required for successful 'wrapping' to occur. This work is significant as it suggests that nano‐ and micron‐sized biological objects such as virus‐like particles, bacteria or mammalian cells—all of which may benefit from additional environmental protection or stabilization in emerging applications—may also be 'wrapped' by this approach. [ABSTRACT FROM AUTHOR]

Adaptive materials with tunable superhydrophobic surfaces promise to impact a range of fluid handling technologies; however, adaptive superhydrophobic materials remain difficult to fabricate, control, and switch rapidly. Here, a versatile method for generating hierarchically structured and adaptive superhydrophobic silicone films for the rational control of surface wettability and droplet adhesion is reported. Specifically, mechanical tension is utilized to manipulate networks of microcracks in nanoporous layers supported on elastomeric silicone films, enabling dynamic modulation of superhydrophobicity and droplet adhesion. The reported mechano‐responsive superhydrophobic surfaces are applied to directional droplet shedding and "no‐loss" droplet transport and are used to generate artificial "skins" with droplet tweezing capabilities. This approach provides materials with enhanced functionality useful to a range of emergent technologies, including adaptive textiles, biocompatible (wearable) sensors, soft robotics, anti‐icing systems, "no‐loss" droplet manipulators, and thermal management devices. [ABSTRACT FROM AUTHOR]

In recent years, the urgent need for reducing the environmental footprint of the building sector has prompted the development of several kinds of new adaptive materials for the built environment. In this work, cutting edge experimental and numerical techniques are used for exploring the potential integration of innovative photoluminescent components in outdoor lighting systems. To this aim, spectroradiometric techniques are used for quantifying the interaction among several compounds and different light sources. Furthermore, numerical simulations are used for evaluating the possible integration of photoluminescent disks in an existing pedestrian path in central Italy. Results show that the proper photoluminescent "active" material should always be coupled to specific light sources, e.g. a mix of yellow and blue afterglow compounds optimizes the afterglow intensity and duration when exposed to a typical white light or to the solar radiation. An optimization procedure could also be used for selecting the number and disposition of photoluminescent disks in real scale applications, as to guarantee the required illuminance levels for pedestrian comfort and sustainability. • Photoluminescent disks are produced and studied for the built environment. • Spectroradiometric analyses of the afterglow are carried out. • Photoluminescent materials-light source is optimized. • Potential real-scale integration is verified via lighting design simulations. • Minimum illuminance requirements are met combining LED and photoluminescent disks. [ABSTRACT FROM AUTHOR]

Recent research on mechano-radicals has provided valuable insights into self-growth and adaptive responsive materials. Typically, mechanophores must remain inert in the absence of force but respond quickly to external tension before other linkages within the polymer network. Azo compounds exhibit promising combinations of mechanical stability and force-triggered reactivity, making them widely used as mechano-radicals in force-responsive materials. However, the activation conditions and behavior of azo compounds have yet to be quantitatively explored. In this study, we investigated the mechanical strength of three azo compounds using single-molecule force spectroscopy. Our results revealed that these compounds exhibit rupture forces ranging from ~500 to 1000 pN, at a loading rate of 3×10 4  pN s -1 . Importantly, these mechanophores demonstrate distinct kinetic properties. Their unique mechanical attributes enable azo bond scission and free radical generation before causing major polymer backbone damage of entire material during polymer network deformation. This fundamental understanding of mechanophores holds significant promise for the development of self-growth materials and their related applications., (© 2024 Wiley-VCH GmbH.)

Electrorheological elastomers (EREs) have viscoelastic properties controllable by external electric fields. For their application, it is necessary to investigate the rheological properties of EREs under various loading conditions. In this work, anisotropic EREs based on a silicone rubber with 10 wt% of PI-Na polyimide particles oriented in an electric field were first obtained. Their elastic properties were evaluated in relation to the frequency and amplitude of strain in an electric field of strength from 0 to 2 kV/mm. The elasticity of the material investigated increased by 50% when the strength of electric field raised to 1.8 kV/mm. The maximum electrorheological effect was found to be at 25°C. [ABSTRACT FROM AUTHOR]

The assessment of the architectural stability of molecular porous materials is not yet a common practice, but critical to their understanding and development. The conformational adaptation of porous materials to guest binding and other chemical dynamics poses a risk of architectural damage, leading to performance deterioration during their prolonged usage. The deformation of the framework backbone and the disconnection of building units are driven by chemical, mechanical, and thermal perturbations, and can be quantitatively described by the term connection completeness. Analytical means that can be used to measure this parameter are presented in order to provide a standard, practical protocol for evaluating architectural damage made to framework materials. Preventive and remedial strategies are proposed for enhancing the architectural integrity of frameworks without compromising their functional mechanisms, paving the way to the design of robust yet adaptive materials. In this way, the discussion on architectural stability is initiated, and readers are encouraged to carefully characterize molecular porous materials for a better understanding of their structure-property relationship. [ABSTRACT FROM AUTHOR]

Adaptivity is an essential trait of life. One type of adaptivity is the reconfiguration of a functional system states by correlating sensory inputs. We report polymer transformers, which can adaptively reconfigure their composition from a state of a mixed copolymer to being enriched in either monomer A or B. This is achieved by embedding and hierarchically interconnecting two chemically fueled activation/deactivation enzymatic reaction networks for both monomers via a joint activation pathway (network level) and an AB linker monomer reactive to both A and B (species level). The ratio of enzymes governing the individual deactivation pathways (our external signals) control the enrichment behavior in the dynamic state. The method shows high programmability of the reconfigured state, rejuvenation of transformation cycles, and quick in situ adaptation. As a proof‐of‐concept, we showcase this dynamic reconfiguration for colloidal surface functionalities. [ABSTRACT FROM AUTHOR]

Bioinspired nanocomposites have made great progress for the fabrication of mechanical high‐performance structural materials, but their properties have thus far been engineered with a focus on static behavior. This contrasts profoundly with the dynamic reconfiguration often observed in living tissues. Here, a first concept is introduced for steady‐state, light‐adaptive reconfiguration of mechanical patterns in bioinspired nanocomposites under dissipative out‐of‐equilibrium conditions. This is realized for green, waterborne cellulose nanofibril/polymer nanopapers by achieving a heterogeneous activation of a photothermal effect. To this end, predefined mechanical patterns are designed by top‐down lamination of bottom‐up engineered bioinspired nanocomposites containing thermoreversible hydrogen bonds, as well as spatially selectively incorporated single‐walled carbon nanotubes for photothermal response. Global irradiation leads to localized photothermal softening by cascading light to heat, and to the dynamization and breakage of the thermoreversible supramolecular bonds, leading to macroscopic reconfiguration and even inversion of mechanical stiff/soft patterns. The altered configuration is only stable in a dissipative steady state and relaxes to the ground state once light is removed. The strategy presents a new approach harnessing the capabilities from top‐down and bottom‐up structuring, and by interfacing it with non‐equilibrium adaptivity concepts, it opens avenues for hierarchical bioinspired materials with anisotropic response in global fields. [ABSTRACT FROM AUTHOR]

Organic granular materials offer a valid alternative for non-biodegradable composites widely adopted in building construction and digital fabrication. Despite the need to find alternatives to fuel-based solutions, current material research in architecture mostly supports strategies that favour predictable, durable and homogeneous solutions. Materials such as soil, due to their physical properties and volatile nature, present new challenges and potentials to change the way we manufacture, built and integrate material systems and environmental factors into the design process. This article proposes a novel fabrication framework that combines high-resolution three-dimensional-printed biodegradable materials with a novel robotic-additive manufacturing process for soil structures. Furthermore, the research reflects on concepts such as affordance and tolerance within the field of digital fabrication, especially in regards to bio-materials and robotic fabrication. Soil as a building material has a long tradition. New developments in earth construction show how earthen buildings can create novel, adaptive and sustainable structures. Nevertheless, existing large-scale earthen construction methods can only produce highly simplified shapes with rough geometrical articulations. This research proposes to use a robotic binder-jetting process that creates novel organic bio-composites to overcome such limitations of common earth constructions. In addition, this article shows how biological polymers, such as polysaccharides-based hydrogels, can be used as sustainable, biodegradable binding agents for soil aggregates. This article is divided into four main sections: architecture and affordance; tolerance versus precision; water-based binders; and robotic fabrication parameters. Digital Soil envisions a shift in the design practice and digital fabrication that builds on methods for tolerance handling. In this context, material and geometrical properties such as material porosity, hydraulic conductivity and natural evaporation rate affect the architectural resolution, introducing a design process driven by matter. Digital Soil shows the potential of a fully reversible biodegradable manufacturing process for load-bearing architectural elements, opening up new fields of application for sustainable material systems that can enhance the ecological potential of architectural construction. [ABSTRACT FROM AUTHOR]

The analysis of scientific publications for rotor systems on the elastic supports made it possible to develop a basic version of the design scheme of active elastic support with controlled quasi-zero stiffness based on adaptive piezoceramic elements. The main components of the mathematical model of the functioning of active elastic supports with controlled quasi-zero stiffness based on adaptive piezoceramic elements are substantiated, which will help create the foundations of a theory for solving the problem of effective vibration protection. Numerical results show the possibility of effective applying of the proposed solution to the problem of rotor vibration damping. [ABSTRACT FROM AUTHOR]

Here, we describe a "smart" polymeric material, which is able to readily detect and discriminate amine vapors. The dynamic imine‐based network can be conveniently prepared by mixing a commercially available, amino‐functionalized polysiloxane with small amounts of a diarylethene dialdehyde. The photoswitchable crosslinker allows for reversible imprinting of custom‐designed patterns on the polymer surface with (sun)light and thus enables noninvasive information storage in the material, which before, during, and after amine exposure can readily be decoded with commonly used smartphone apps. This feature along with the self‐healing nature of the dynamic polymer, an easy recycling and manufacturing procedure, and the overall low cost and toxicity render this material advantageous to develop low‐cost and practical amine sensing devices for the broad public. © 2019 The Authors. Journal of Polymer Science Part A: Polymer Chemistry published by Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2378–2382 [ABSTRACT FROM AUTHOR]

Abstract: Controlling supramolecular growth at solid surfaces is of great importance to expand the scope of supramolecular materials. A dendritic benzene‐1,3,5‐tricarboxamide peptide conjugate is described in which assembly can be triggered by a pH jump. Stopped‐flow kinetics and mathematical modeling provide a quantitative understanding of the nucleation, elongation, and fragmentation behavior in solution. To assemble the molecule at a solid–liquid interface, we use proton diffusion from the bulk. The latter needs to be slower than the lag phase of nucleation to progressively grow a hydrogel outwards from the surface. Our method of surface‐assisted self‐assembly is generally applicable to other gelators, and can be used to create structured supramolecular materials. [ABSTRACT FROM AUTHOR]

ABSTRACT: Liquid crystal polymer networks (LCNs) lead the research geared toward macroscopic motion of materials. These actuators are molecularly programed to adapt their shape in response to external stimuli. Non‐photo‐responsive thin films of LCNs covered with heat absorbers (e.g., graphene or ink) are shown to continuously oscillate when exposed to light. The motion is governed by the heat dissipated at the film surface and the anisotropic thermal deformation of the network. The influence of the LC molecular alignment, the film thickness, and the LC matrix on the macroscopic motion is analyzed to probe the limits of the system. The insights gained from these experiments provide not only guidelines to create actuators by photo‐thermal or pure photo‐effects but also a simple method to generate mechanical oscillators for soft robotics and automated systems. © 2018 The Authors. Journal of Polymer Science Part A: Polymer Chemistry Published by Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 1331–1336 [ABSTRACT FROM AUTHOR]

Abstract: Chemical reactions are classically controlled by the judicious choice of functional groups as well as external factors such as temperature and catalysts. However, the use of light‐induced reactions not only offers precise temporal and spatial control, but critically allows highly specific reaction channels to be selectively addressed through wavelength and intensity, thereby enabling targeted covalent bonds to be made and broken. Photoreversible cycloadditions are the most promising candidates to seize the outlined potential upon selective cyclization and cycloreversion, but are today still far from fulfilling these expectations. The current Minireview critically explores the current challenges in the application of photoreversible cycloadditions and discusses the steps necessary to realize their potential in molecular biology, biomimetic systems, 3D laser lithographic processes, and advanced soft matter materials with reprogrammable and self‐healing properties. [ABSTRACT FROM AUTHOR]

Abstract: Dynamic controllability of self‐organized helical superstructures in spatial dimensions is a key step to promote bottom‐up artificial nanoarchitectures and functional devices for diverse applications in a variety of areas. Here, a light‐driven chiral overcrowded alkene molecular motor with rod‐like substituent is designed and synthesized, and its thermal isomerization reaction exhibits an increasing structural entropy effect on chemical kinetic analysis in anisotropic achiral liquid crystal host than that in isotropic organic liquid. Interestingly, the stimuli‐directed angular orientation motion of helical axes in the self‐organized helical superstructures doped with the chiral motors enables the dynamic reconfiguration between the planar (thermostationary) and focal conic (photostationary) states. The reversible micromorphology deformation processes are compatible with the free energy fluctuation of self‐organized helical superstructures and the chemical kinetics of chiral motors under different conditions. Furthermore, stimuli‐directed reversible nonmechanical beam steering is achieved in dynamic hidden periodic photopatterns with reconfigurable attributes prerecorded with a corresponding photomask and photoinduced polymerization. [ABSTRACT FROM AUTHOR]

Functional materials that respond to external stimuli are of major current interest. In particular, supramolecular systems that can interact with their surroundings, adapt to environmental changes and evolve with are even more fascinating, yet challenging. Combining the rich physico-chemical properties featured by metal centres with characteristics typical of classical organic polymers, metallopolymers or metallo-supramolecular polymers can be prepared, depending on their static versus dynamic structural features. Additionally, multiple and orthogonal functionalities can be encoded in their chemical structure affording materials with widespread potential applications to be employed as 'smart' materials for advanced technologies. In this Concept article, selected examples of metal-containing polymers will be described demonstrating large potentialities of such systems for creating stimuli-responsive materials with special emphasis for those showing optical applications. [ABSTRACT FROM AUTHOR]

3D printing is a powerful emerging technology for the tailored fabrication of advanced functional materials. This Review summarizes the state-of-the art with regard to 3D laser micro- and nanoprinting and explores the chemical challenges limiting its full exploitation: from the development of advanced functional materials for applications in cell biology and electronics to the chemical barriers that need to be overcome to enable fast writing velocities with resolution below the diffraction limit. We further explore chemical means to enable direct laser writing of multiple materials in one resist by highly wavelength selective (λ-orthogonal) photochemical processes. Finally, chemical processes to construct adaptive 3D written structures that are able to respond to external stimuli, such as light, heat, pH value, or specific molecules, are highlighted, and advanced concepts for degradable scaffolds are explored. [ABSTRACT FROM AUTHOR]

We describe single-chain polymer nanoparticles (SCNPs) possessing intramolecular dynamic covalent crosslinks that can transform into polymer films through a molecular recognition-mediated crosslinking process. The SCNPs utilise molecular recognition with surface-immobilised proteins to concentrate upon a substrate, bringing the SCNPs into close spatial proximity with one another and allowing their dynamic covalent crosslinkers to undergo intra- to interpolymer chain crosslinking leading to the formation of polymeric film. SCNPs must possess both the capacity for specific molecular recognition and a dynamic nature to their intramolecular crosslinkers to form polymer films, and an investigation of the initial phase of film formation indicates it proceeds from features which form upon the surface then grow predominantly in the xy directions. This approach to polymer film formation presents a potential method to 'wrap' surfaces displaying molecular recognition motifs-which could potentially include viral, cellular and bacterial surfaces or artificial surfaces displaying multivalent recognition motifs-within a layer of polymer film. [ABSTRACT FROM AUTHOR]

The native extracellular matrix is highly dynamic with continuous mutual feedback between cells being responsible for many important cell function regulators. However, establishing bidirectional interaction between complex adaptive microenvironments and cells remains elusive. Herein an adaptive biomaterial based on lysozyme monolayers self-assembled at a perfluorocarbon FC40-water interface is reported. The dynamic adaptivity of interfacially assembled protein nanosheets is modulated independently of bulk mechanical properties by covalent crosslinking. This provides a scenario to establish bidirectional interactions of cells with liquid interfaces of varying dynamic adaptivity. This is found that growth and multipotency of human mesenchymal stromal cells (hMSCs) are enhanced at the highly adaptive fluid interface. The multipotency retention of hMSCs is mediated by low cell contractility and metabolomic activity involving the continuous mutual feedback between the cells and materials. Consequently, an understanding of the cells' response to dynamic adaptivity has substantial implications for regenerative medicine and tissue engineering., (© 2023 Wiley-VCH GmbH.)

Eukaryotic cells have inner compartments (organelles), each with distinct properties and functions. One mimic of this architecture, based on biopolymers, is the multicompartment capsule (MCC). Here, MCCs in which the inner compartments are chemically unique and "smart," i.e., responsive to distinct stimuli in an orthogonal manner are created. Specifically, one compartment alone is induced to degrade when the MCC is contacted with an enzyme while other compartments remain unaffected. Similarly, just one compartment gets degraded upon contact with reactive oxygen species generated from hydrogen peroxide (H 2 O 2 ). And thirdly, one compartment alone is degraded by an external, physical stimulus, namely, by irradiating the MCC with ultraviolet (UV) light. All these specific responses are achieved without resorting to complicated chemistry to create the compartments: the multivalent cation used to crosslink the biopolymer alginate (Alg) is simply altered. Compartments of Alg crosslinked by Ca 2+ are shown to be sensitive to enzymes (alginate lyases) but not to H 2 O 2 or UV, whereas the reverse is the case with Alg/Fe 3+ compartments. These results imply the ability to selectively burst open a compartment in an MCC "on-demand" (i.e., as and when needed) and using biologically relevant stimuli. The results are then extended to a sequential degradation, where compartments in an MCC are degraded one after another, leaving behind an empty MCC lumen. Collectively, this work advances the MCC as a platform that not only emulates key features of cellular architecture, but can also begin to capture rudimentary cell-like behaviors., (© 2023 The Authors. Small published by Wiley-VCH GmbH.)

Various aldehyde-containing photoswitches have been developed whose reactivity toward amines can be controlled externally. A thermally stable bifunctional diarylethene, which in its ring-closed form exhibits imine formation accelerated by one order of magnitude, was used as a photoswitchable crosslinker and mixed with a commercially available amino-functionalized polysiloxane to yield a rubbery material with viscoelastic and self-healing properties that can be reversibly tuned by irradiation. [ABSTRACT FROM AUTHOR]

Topological phononic crystals, alike their electronic counterparts, are characterized by a bulk-edge correspondence where the interior of a material dictates the existence of stable surface or boundary modes. In the mechanical setup, such surface modes can be used for various applications such as wave guiding, vibration isolation, or the design of static properties such as stable floppy modes where parts of a system move freely. Here, we provide a classification scheme of topological phonons based on local symmetries. We import and adapt the classification of noninteracting electron systems and embed it into the mechanical setup. Moreover, we provide an extensive set of examples that illustrate our scheme and can be used to generate models in unexplored symmetry classes. Our work unifies the vast recent literature on topological phonons and paves the way to future applications of topological surface modes in mechanical metamaterials. [ABSTRACT FROM AUTHOR]

Nature provides design paradigms for adaptive, self-healing, and synergistic high-performance structural materials. Nacre's brick-and-mortar architecture is renowned for combining stiffness, toughness, strength, and lightweightness. Although elaborate approaches exist to mimic its static structure and performance, and to incorporate functionalities for the engineering world, there is a profound gap in addressing adaptable mechanical properties, particularly using remote, quick, and spatiotemporal triggers. Here, we demonstrate a generic approach to control the mechanical properties of nacre-inspired nanocomposites by designing a photothermal energy cascade using colloidal graphene as light-harvesting unit and coupling it to molecularly designed, thermoreversible, supramolecular bonds in the nanoconfined soft phase of polymer/nanoclay nacre-mimetics. The light intensity leads to adaptive steady-states balancing energy uptake and dissipation. It programs the mechanical properties and switches the materials from high stiffness/strength to higher toughness within seconds under spatiotemporal control. We envisage possibilities beyond mechanical materials, for example, light-controlled (re)shaping or actuation in highly reinforced nanocomposites. [ABSTRACT FROM AUTHOR]

Fluid actuated cellular structures are morphing structures inspired by the nastic movement of plants. These materials have a wide array of applications from morphing aircraft wings to soft robotics. The nonlinear shape-morphing behaviors of the fluid actuated cellular structures composed of randomly distributed polygonal motor cells are investigated in this work. A new multiscale modeling framework based on multiscale finite-element methods is proposed to simulate the nonlinear behaviors of such adaptive materials with irregular polygonal microstructures. The multiscale displacement and hydraulic pressure base functions are firstly constructed to establish the relationship between the microstructures of the fluidic actuating cells and the macroscopic deformation on the polygonal coarse-scale mesh. Then, the corotational formulation for geometrically nonlinear analysis is integrated to this multiscale method to decompose the nonlinear deformations of the polygonal coarse-grid element into rigid-body motions and pure deformational displacements. In addition, a master--slave displacement relationship is employed to ensure the displacement continuity at the interface between the polygonal multiscale coarse-grid elements and the traditional fine-scale elements in a same computational model. Several representative examples including a smart wing structure are investigated to validate the accuracy and efficiency of the proposed polygonal multiscale corotational method. [ABSTRACT FROM AUTHOR]