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Mechanoresponsive smart windows can modulate optical transparency by mechanical actuation, showing the advantages of low cost, energy efficiency, and chemical stability. To date, mechanoresponsive smart windows are mainly built on periodic nano- or microstructures such as arrays, wrinkles, 3D photonic crystals, and polymeric nanocomposites. However, the production of periodic structures requires multiple and complicated processes, which restricts large-scale manufacturing of mechanoresponsive smart windows for practical application. Here, we report one-pot fabrication of poly methacrylic acid sodium salt (PMANa)/polyurethane (PU) mechanoresponsive smart windows with a nonperiodic naturally occurring microsized structure. The obtained smart windows display a high contrast ratio and stable transparency switching behavior under 80% tensile strain over 1000 cycles and have a large breaking elongation of 820%. It offers a promising platform for designing and fabricating multifunctional optical devices including anticounterfeiting labels and dynamical light gratings.

Multifunctionality is an essential feature for the application of soft actuators in the fields of soft robotics, flexible electronics, and energy generators. Accordingly, liquid crystal polymer networks (LCNs) afford a promising platform for designing multifunctional soft actuators due to their reversible, programmable, and multi-stimuli-responsive shape changing behaviors via the self-organization of liquid crystals. Although the introduction of functional components (e.g. conductive and magnetic fillers) has been considered to be an effective approach to exploit multifunctional LCN soft actuators, it remains a great challenge to integrate a particular role of functional components while maintaining inherent shape changing capabilities of LCNs. Herein, we report a facile method to achieve multifunctional LCN soft actuators by directly injecting the desired functional component in the liquid state into LCN tubular actuators. In our design, the LCN tubular actuators prepared via the mechanical programming process act as a structural framework, providing reversible shape changing behaviors with a large strain both in length and inner diameter. To introduce conductive functionality, liquid metals (LMs) are selected as the functional component due to their ultrahigh conductivity and controllable melting point. The multifunctional LCN soft actuators elegantly couple ultrahigh conductivity of the LMs and original shape changing behaviors of the LCN tubular actuators and are demonstrated as a thermal-responsive electrical switch.

An elastomer with both mechanical robustness and self-healing capability is desired and is much needed to meet the increasing demand for next-generation soft electronics that can not only remotely sense and wirelessly communicate but also autonomically self-heal once damaged. It has long been a challenge for materials scientists and engineers to design and process such type of polymer since mechanical robustness and self-healing are largely contradictory in nature. Herein, elastomer networks based on synergetic triple dynamic non-covalent interactions are developed through a polyurethane–polyethylenimine (PU–PEI) colloidal complex. The PU–PEI elastomer exhibits a maximum tensile strength of 15.8 MPa, breaking elongation of 1360% and toughness of 127.8 MJ m−3, which are superior to those of the current suite of self-healable elastomers at room temperature. Meanwhile, the dynamic hydrogen bonds, ionic interactions and polymer entanglement interactions yield a self-healing efficiency of 86% in 3 hours in water at room temperature. The self-healing behavior can also autonomically occur in humid air. In addition to its superior mechanical properties, the PU–PEI elastomer is transparent, recyclable and solution processable. It was found that the PU–PEI colloidal complex could be doped with conductive fillers to form a printable composite ink so as to enable a self-healable 2.4 GHz Wi-Fi soft antenna, demonstrating the potential of the developed elastomer for application in integral soft electronics.

The controllable deposition of silver (Ag) nanoparticle onto functional materials is beneficial for a wide range of applications including conductive composites and electrically conductive adhesives. While the deposition of Ag nanoparticles on various substrates has been extensively studied, the fine control of the size, dispersion, growth, and colloidal stability of silver nanoparticles on complex high aspect-ratio nanomaterials is still a challenge. In this work, we report the synthesis of conductive composites of cellulose nanocrystal coated with a uniform layer of Ag nanoparticle. For this, we have used polyvinylpyrrolidone (PVP) as a coupling agent for the formation of polydopamine (PDA) on cellulose nanocrystal and the subsequent formation of uniform Ag nanoparticle. With continuously and closely packed Ag nanoparticles, the as-prepared conductive composites demonstrated promising applications as conductive composite paste for direct writing and as a co-filler for hybrid electrically conductive adhesives. As a conductive composite paste, no high-temperature sintering is required when it is written on paper, glass slide and fabrics to form conductive patterns. When served as a co-filler in electrically conductive adhesives, a small amount of conductive composites (1.5 wt%) largely enhanced conductivity and lap shear strength, while maintaining the excellent viscosity for easy operation in stencil printing and 3D printing.

Robotics is a frontal interdisciplinary subject across the fields of mechanical engineering, chemical and materials engineering, artificial intelligence, and nanotechnology. Robotic devices with a variety of frameworks, functionalities, and actuation modes have been developed and employed in the manufacture of advanced materials and devices with improved efficiency and automation. In recent years, soft robots have attracted a significant amount of interest among scientific researchers and technological engineers because they can offer the desired safety, adaptability, sensibility, and dexterity that conventional robotics cannot deliver. To date, emulating living creatures in nature has been a promising approach to design soft robots. For living creatures, both body deformation and their surface characteristic are essential for them to function in dynamic ecological environments. Body deformation offers athletic ability while surface characteristics provide extraordinary adaptable interactions with the environment. In this article, we discuss the recent progress of emulating the body deformation of living creatures such as shrinking/expanding, bending, and twisting and programmable deformations based on the manipulation of shape-changing behaviors of liquid-crystal polymeric materials (LCPs) and the interfacial technologies to build up various microstructures similar to the interface of living creatures. We further review the pioneering work that integrates interfacial engineering and the shape-changing modulation of LCPs to develop biomimetic soft robotic devices. We also provide an outlook for opportunities and challenges in the design and fabrication of advanced biomimetic soft robots based on the synergetic combination of interfacial engineering and shape-changing modulation.

In this work, we report a methanol-facilitated approach to directly use aqueous Poly(3,4-ethylenedioxythiophene):Poly(styrene sulfonate) (PEDOT:PSS) in the silver/epoxy composites for preparation of highly electrically conductive adhesives (ECAs) and an investigation of the interaction between PEDOT:PSS nano-gels and silver microflakes. PEDOT:PSS nano-gel (18

Utilization of bauxite residue is an urgent issue confronting the worldwide alumina industry. A CaTiO3-rich material has been successfully collected from bauxite residues based on our previous work, and the possibility of applying this obtained CaTiO3 as photocatalyst for degradation of rhodamine B was evaluated in this study. X-ray diffraction, Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, X-ray photoelectron spectroscopy, UV–vis spectroscopy, photoluminescence microscopy, and Brauner-Emmet-Teller surface area analyzer were employed to characterize the CaTiO3 samples. Interactive effects of dominant factors on degradation of rhodamine B were examined through surface response methodology and optimal conditions were obtained. H3PO4 acidification was effective to enhance the photocatalytic activity of CaTiO3. More than 10 h was required for RhB degradation in presence of CaTiO3 while only 3 h was needed to achieve 85% removal of RhB using the acidified CaTiO3. CaTiO3 has larger band gap and lower separation efficiency of photoelectrons-hole pairs than TiO2, but H3PO4 acidification significantly reduced the recombination of photoelectrons-hole pairs and thus made more photoelectrons/holes participate in reactions. This study has validated a promising routine towards fully comprehensive utilization of bauxite residues, and simultaneously addressed a novel idea for using solid-waste to treat wastewater, thereof was very favorable to the sustainable development of environment.

We report on the discovery of an interesting dual colorimetric and conductometric response of synthesized water-based silver-decorated polypyrrole (Ag/PPy) nanowire to organic solvents, and the possible fabrication of a volatile organic compounds (VOCs) sensor based on the stimuli-responsive Ag/PPy nanocomposites. The dual-responsive nature of this material allows for a straightforward way to differentiate various VOCs within a broad polarity range by noncontact optical means via color transition, but also can provide highly accurate quantitative identification of each VOC by electronic detection.

A mussel-inspired one-step modification has been developed to coat polydimethylsiloxane (PDMS) sponges with polydopamine/octadecylamine for oil sorption. The durable and hydrophobic sponge with self-healing properties may be useful to prevent the degradation by graphite particles residing on the material surfaces and maintain the oil/water separation efficiency. The coated PDMS sponge showed oil absorbency in the range from 830% to 4300% for various organic solvents, with the maximum absorption capacity reaching up to 43 times of its weight. Furthermore, PDMS sponges showed little loss of their absorption capacities and original weights after 20 absorbing/recovering cycles.