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Summary Physical unclonable function (PUF) is a cornerstone of anticounterfeiting. However, conventional PUF key-based secure tags encounter several bottlenecks, such as complicated manufacturing, specialized and tedious readout, long authentication time, and insufficient stability. Here, we utilize various two-dimensional materials (2DMs), including Ti3C2Tx MXene and graphene oxide, to construct multigenerational microstructures as PUF patterns. Two intermediate treatments, cation intercalation and moisture-induced lubrication, are introduced in between sequential contractions to engineer the multiscale patterns in a transfer-free and scalable fashion. A deep learning (DL)-facilitated software is developed to pre-categorize the hierarchical topographies with classifiable features. Thereafter, the search-and-compare is conducted within a smaller database to shorten the overall authentication time. The synergy between 2DM tags and DL-facilitated software enables a reliable and environmentally stable anticounterfeiting technology, DeepKey, showing superior encoding capacity (>10144,494) and short authentication time (∼3.5 min). Our 2DM anticounterfeiting tag is finally integrated with QR codes to provide two-layer information security.

Silicone elastomers with high mechanical stability have been conventionally adopted for the fabrication of emerging soft robots. However, these elastomers exhibit limited electrical and thermal properties that restrict the development of functional soft robots. A promising approach is to integrate carbon nanomaterials into hydrogels to develop multifunctional robotic skin with high deformability and diverse built-in functions for fabricated soft machines. Herein, a scalable approach was developed to fabricate a conductive hydrogel by integrating pristine multi-walled carbon nanotubes (MWNTs) into gelatin solution followed by the introduction of a crosslinking agent (i.e., glutaraldehyde). After the addition of glutaraldehyde, the viscosity of MWNT-gelatin dispersion increased with time, and a viscous precursor paste for conductive hydrogels was achieved for various scalable coating techniques including doctor blading. After large-area printing, the MWNT-gelatin paste continued to crosslink, and an MWNT-integrated gelatin hydrogel (MW-hydrogel) was obtained. The MW-hydrogels were highly deformable, and the electrical resistance of conductive MW-hydrogels was responsive to various mechanical deformations, enabling their applications in electronic robotic skin to monitor the actuations of soft robots in real time. Also, the MW-hydrogels were further utilized as flame-retardant skin for a soft robotic gripper, which could manipulate and rescue irregularly shaped objects from a fire scene.

As an important part in electrochromic (EC) devices, electrolytes usually have poor mechanical strength, which limits the development of flexible EC devices especially in tailorability. Here, the poly(e-caprolactone) (PCL) electrospun mats filled with silica (SiO2) nanoparticles were prepared. Through reasonable optimization, the PCL/SiO2 nanofibrous mats with the mass ratio of 97:3 between PCL and SiO2 showed an enhanced electrolyte uptake of 805.0%, which led to a high ionic conductivity of 5.2 mS·cm−1. Due to the formation of interpenetrated nanofiber network, the breaking strength of the gel electrolytes reached up to 9.94 MPa. Based on the gel electrolyte with high ionic conductivity and good mechanical strength, the assembled flexible EC devices showed good EC properties. More importantly, these flexible EC devices can be tailored into different shapes without obvious performance degradation, which is conducive to the application of EC devices in many novel fields.

Photodynamic therapy (PDT) has been approved for the clinical treatment of cancers. Photosensitizer (PS) is a crucial element of PDT. In the current study, in vitro and in vivo evaluation of a chlorin-based photosensitizer KAE® was performed.The physicochemical characteristics of KAE® were compared with chlorin e6. The intracellular distribution of KAE® in HeLa cells was observed by laser scanning confocal microscopy. Reactive oxygen species (ROS) generation was detected through a 2', 7-dichlorodihydrofluorescein diacetate probe. The pharmacokinetics of KAE® was studied in mice. The photodynamic activities of KAE® and porphyrin based PSs were compared both in vitro and in vivo. The biosafety of KAE® in mice was evaluated by pathological section observation, blood routine examination and biochemistry assays.KAE® was readily dissolved in an aqueous solvent in a clinically acceptable concentration and showed a strong absorption at around 660 nm. Most of KAE® was located in the mitochondria of the tumor cells. Compared with hematoporphyrin derivative and 5-aminolevulinic acid, KAE® displayed a higher efficiency in cell killing. Furthermore, it could be completely eliminated from mouse body in 2 days. KAE® had no toxicity to mice under the tested dosage.Our results suggested that KAE® is an effective and safe PS for PDT in cancer therapy and has a promising prospect for clinical application.

Recently, pressure/strain sensor based on triboelectric nanogenerator (TENG) has gained great attentions for monitoring daily health status and robotic research fields, because of their simple device structures and self-powered feature. However, higher sensitivity and stretchability are still demanded for satisfying the practical applications. In this work, a self-powered pressure and strain sensor was achieved by utilizing crumpled MXene film as the single-electrode mode TENG. Benefiting from the reconfigurable behavior of the crumpled structure, the MXene TENG showed a maximum areal strain and linear tensile ratio of 2150% and 400%, respectively. Meanwhile, because of the enlarged contact area between triboelectric layers, the output power density of the MXene TENG with micro-crumples was highly improved by 36 times. Therefore, the as prepared sensor exhibited excellent sensitivity of 2.35 V kPa−1 under pressures from 0.3 to 1.0 kPa, which is superior to majority of the reported sensors based on tribo-/piezo- electricity. In addition, the sensor can be easily attached to human joints to capture and collect the complicated movement signals. By combining with Bluetooth transmission technology, wireless real-time monitoring was realized through transmitting human movement signals to a mobile phone App.

It is attractive to develop multifunctional materials for practical applications. Herein, heteroatom-doped hierarchically porous carbons (HPCs) are prepared through a simple pyrolysis of monolithic hydrogels derived from glucose, followed by chemical activation using KOH as an activator at 600–1000 °C. With different activation temperature, the pore structure and surface chemistry of the resulting HPCs can be easily tuned and the corresponding performances in supercapacitors, CO2 capture and dye adsorption are further investigated. HPC800 with the largest micropore volume (0.58 cm3 g−1) exhibits a high specific capacitance of 249 F g−1 at 1 A g−1 and an excellent cycling stability with 94% of the capacitance retention after 1000 cycles as supercapacitors electrodes. Meanwhile, HPC800 shows the remarkable adsorption capacity of CO2 (4.4 mmol g−1 at 25 °C, 1 atm). For methylene blue (MB) adsorption, the maximum adsorption capacity of 720 mg g−1 is obtained on HPC1000 with the highest specific surface area (2302 m2 g−1) and total pore volume (1.10 cm3 g−1). The CO2 and MB adsorption capacities are both higher than most of the reported adsorbents. It is demonstrated that CO2 and MB adsorption capacity are determined by the volume of pore with diameter

In this study, porous carbon aerogel (CA) was synthesized with D-glucose, ammonium persulfate and aniline by a hydrothermal carbonization method. It was reported for the first time as an excellent catalyst for activating persulfate (PS) to degrade rhodamine B (RhB). The morphology of CA was characterized, exhibiting microporous and mesoporous structures. The solution pH of 3, 5, 7 and 9 showed slight impact on the degradation of RhB; however, when the pH increased to 11, the removal of RhB decreased. The PS concentration and CA dosage played a key role in the RhB degradation, and the activation energy was calculated to be 22.11 kJ/mol. Electron paramagnetic resonance (EPR) spectra suggested that neither sulfate radical (SO4 −) nor hydroxyl radical ( OH) was generated from the PS activation. The radical quenching experiments also confirmed that CA activated PS in a non-radical pathway. It was indicated that PS bonded with C C in the sp2 hybridized system could directly degrade RhB. The defective edges at the boundary of CA also facilitated the RhB removal. This work presented a green material with both excellent catalytic performance and high regeneration possibility in the heterogeneous metal-free PS activation, providing a new strategy in water treatment.

The device assembly plays an important role in affecting the electrochromic (EC) performance of an electrochromic device (ECD). Here, WO 3 ·0.33H 2 O films are fabricated by a hydrothermal method and then PEDOT:PSS are spin-coated on the surface of WO 3 ·0.33H 2 O films. Finally, the WO 3 ·0.33H 2 O/PEDOT films are assembled with electrodeposited prussian blue (PB) to fabricate the WO 3 ·0.33H 2 O/PEDOT-PB complementary electrochromic devices (ECDs). Compared with pure WO 3 ·0.33H 2 O and WO 3 ·0.33H 2 O/PEDOT single-active-layer structure ECDs, the complementary ECD exhibits higher optical modulation, higher coloration efficiency and faster response time, which would provide a promising platform for energy-saving smart (ESS) window.

Hydrogels possess exceptional physical and chemical properties that render them appealing components for soft actuators, wearable technologies, healthcare devices, and human interactive robots. Especially, the stimuli-responsive hydrogels can sense and perform smart functions in the presence of various stimuli that collectively contribute to the intelligence of the soft machine systems. Furthermore, facile modification of hydrogels with other functional groups/additives/nanofillers substantially expands their functionalities and further broadens the scope of their application. Designing suitable hydrogels with adequate capabilities and engineering effective configurations are of supreme importance for the development of advanced hydrogel-based soft machines. Herein, this review summarizes recent advances of stimuli-responsive hydrogels in multifunctional soft machines, such as robotics, actuators, and sensors. Functions including multistimuli responsiveness, self-healing, and high biocompatibility can be endowed to the soft machines through designing advanced hydrogel materials, which would not be possible with an approach based on conventional elastic materials (e.g. rubbers, elastomers). To close, future opportunities and challenges this field faces are emphasized and discussed for the development of exciting new hydrogel-based devices in real-world conditions.

Recent years have witnessed continuing advances in solar evaporation technologies to achieve strong synergy among sufficient water supply, efficient light absorption, and favorable heat localization. Still, challenges remain in the fabrication of solar evaporation devices with synergistic performance in a scalable fashion. Herein, we develop a scalable fabrication process involving multi-scale and multi-interface engineering to achieve high-performance and large-area solar evaporation devices. At nanoscale, light-absorbing carbon nanotubes (CNTs) are complexed with hydrophilic cellulose nanofibers (CNFs) to form the nanocomposite inks of CNT-CNF (c-CNT) with tunable viscosity for doctor blading on ethanol-diffused polystyrene (E-PS) films. Through one-step thermal treatment, device shrinkage and substrate foaming are triggered at multi-interfaces to synchronously induce (1) the creation of microscale crumpled c-CNT textures with dual-improved water supply and light absorption and (2) the generation of mesoscale pores in PS substrates with dual-suppressed thermal conduction and radiation. Contributed by the synergistic designs, the solar evaporation device demonstrates a high evaporation rate of 1.41 kg m−2 h−1 and a conversion efficiency of 95.8% at an extremely low loading of photothermal materials (0.25 mg cm−2). A large-area solar evaporation panel is realized to highlight the practical consideration toward more impactful solar evaporation exploitation.

A porous carbon aerogel (CA) was prepared to activate persulfate (PS) for the removal of phenol. The adsorption of phenol on CA and its removal in CA/PS system was fitted to a second-order model and first-order kinetic model, respectively. Influencing factors of CA/PS such as pH, CA dose, PS concentration, phenol concentration and temperature were investigated. CA/PS presented good performance on phenol removal over a pH range of 3–11 with the highest removal obtained at pH 7. Four kinds of organic pollutants including tetracycline, Rhodamine B, Safranine T and malachite green were investigated in the CA/PS system, proving that the adsorption of the contaminants benefitted their subsequent oxidation removal. The removal of aromatic compounds (phenol, p-diphenol, p-chlorophenol, and p-nitrophenol) in CA/PS system followed a decreasing order of hydroxyl > chlorine > nitro. The radical scavenging experiments suggested the removal of phenol was mainly through a non-radical pathway. The study presented the preparation and application of a green catalyst to activate PS, which is very promising for the development of the technology and the treatment of phenolic wastewater.