2D materials are of particular interest in light‐to‐heat conversion, yet challenges remain in developing a facile method to suppress their light reflection. Herein, inspired by the black scales of ...Bitis rhinoceros, a generalized approach via sequential thermal actuations to construct biomimetic 2D‐material nanocoatings, including Ti3C2Tx MXene, reduced graphene oxide (rGO), and molybdenum disulfide (MoS2) is designed. The hierarchical MXene nanocoatings result in broadband light absorption (up to 93.2%), theoretically validated by optical modeling and simulations, and realize improved light‐to‐heat performance (equilibrium temperature of 65.4 °C under one‐sun illumination). With efficient light‐to‐heat conversion, the bioinspired MXene nanocoatings are next incorporated into solar steam‐generation devices and stretchable solar/electric dual‐heaters. The MXene steam‐generation devices require much lower solar‐thermal material loading (0.32 mg cm−2) and still guarantee high steam‐generation performance (1.33 kg m−2 h−1) compared with other state‐of‐the‐art devices. Additionally, the mechanically deformed MXene structures enable the fabrication of stretchable and wearable heaters dual‐powered by sunlight and electricity, which are reversibly stretched and heated above 100 °C. This simple fabrication process with effective utilization of active materials promises its practical application value for multiple solar–thermal technologies.
Inspired by the black scales of Bitis rhinoceros, a generalized approach is developed via sequential thermal actuations to construct biomimetic 2D‐material nanocoatings, including Ti3C2Tx MXene, reduced graphene oxide, and MoS2. The hierarchical MXene nanocoatings result in broadband light absorption, and realize improved light‐to‐heat performance, demonstrating extremely practical application value in solar steam generation and wearable thermal management.
In the emerging Internet of Things, stretchable antennas can facilitate wireless communication between wearable and mobile electronic devices around the body. The proliferation of wireless devices ...transmitting near the human body also raises interference and safety concerns that demand stretchable materials capable of shielding electromagnetic interference (EMI). Here, an ultrastretchable conductor is fabricated by depositing a crumple‐textured coating composed of 2D Ti3C2Tx nanosheets (MXene) and single‐walled carbon nanotubes (SWNTs) onto latex, which can be fashioned into high‐performance wearable antennas and EMI shields. The resulting MXene‐SWNT (S‐MXene)/latex devices are able to sustain up to an 800% areal strain and exhibit strain‐insensitive resistance profiles during a 500‐cycle fatigue test. A single layer of stretchable S‐MXene conductors demonstrate a strain‐invariant EMI shielding performance of ≈30 dB up to 800% areal strain, and the shielding performance is further improved to ≈47 and ≈52 dB by stacking 5 and 10 layers of S‐MXene conductors, respectively. Additionally, a stretchable S‐MXene dipole antenna is fabricated, which can be uniaxially stretched to 150% with unaffected reflected power <0.1%. By integrating S‐MXene EMI shields with stretchable S‐MXene antennas, a wearable wireless system is finally demonstrated that provides mechanically stable wireless transmission while attenuating EM absorption by the human body.
2D titanium carbide–based ultrastretchable conductors are fabricated by harnessing the surface instability of pre‐stretched latex, showing strain‐invariant performance in stretchable electromagnetic interference (EMI) shields and wearable wireless communicators, respectively. Finally, a wearable antenna with on‐site EM protection for the human body is demonstrated, which exhibits mechanically stable and efficient wireless communication and shielding performance.
Microsupercapacitors (MSCs) with neutral multivalent electrolytes are safer, cheaper, and exhibit higher theoretical energy densities compared with the MSCs with acidic and alkaline electrolytes. ...Multivalent charge carriers (e.g., Mg2+, Zn2+) in the MSCs with Ti3C2Tx MXene electrodes have not been demonstrated, which could theoretically achieve higher specific capacitances and energy densities. However, because of the larger size of multivalent charge carriers, the MXene electrodes require further modifications to facilitate reversible electrochemical reactions. Herein, through spontaneous intercalation of various metal ions into MXene multilayers, twelve metal ion intercalated MXene electrodes (Mn+‐MXene) are fabricated and demonstrate improved electrochemical performance. Different nanopillar effects are observed between divalent Be2+ and trivalent Al3+ intercalants, which are systematically investigated by electrochemical impedance spectroscopy and molecular dynamics simulation. Among all Mn+‐MXene electrodes, the Be2+‐MXene electrode largely facilitates the charge‐transfer process with minimal disturbance of electrolyte diffusion rates, showing improved specific capacitances and high rate performance in univalent (Li2SO4, Na2SO4, K2SO4) and multivalent electrolytes (BeSO4, MgSO4, ZnSO4). Finally, flexible Be2+‐MXene MSCs with neural ZnSO4 gel electrolytes are fabricated, demonstrating superior areal capacitances (77.2 mF cm−2) and high energy density (3.86 μWh cm−2 at 0.12 mW cm−2) together with high user safety.
A facile metal‐ion intercalation technology is developed to enhance the electrochemical performance of Ti3C2Tx MXene in various neutral multivalent electrolytes. Twelve metal ions are intercalated into MXene electrodes. The Be2+‐intercalated MXene electrode facilitates the charge‐transfer process with minimal disturbance of electrolyte diffusion rates. Finally, Be2+‐MXene microsupercapacitors with neural ZnSO4 gel electrolytes demonstrate superior areal capacitances together with high user safety.
Cephalopod skin, which is capable of dynamic optical camouflage, environmental perceptions, and herd communication, has long been a source of bio‐inspiration for developing soft robots with ...incredible optoelectronic functions. Yet, challenges still exist in designing a stretchable and compliant robotic skin with high‐level functional integration for soft robots with infinite degrees of freedom. Herein, an emerging 2D material, Ti3C2Tx MXene, and an interfacial engineering strategy are adopted to fabricate the soft robotic skin with cephalopod skin‐inspired multifunctionality. By harnessing interfacial instability, the MXene robotic skin with reconfigurable microtextures demonstrates tunable infrared emission (0.30–0.80), enabling dynamic thermal camouflage for soft robots. Benefiting from the intrinsic Seebeck effect, crack propagation behaviors as well as high electrical conductivity, the MXene robotic skins are tightly integrated with thermal/strain sensation capabilities and can serve as a deformable antenna for wireless communication. Without additional electronics installed, the soft robots wearing the conformal MXene skins perform adaptive thermal camouflage based on the thermoelectric feedback in response to environmental temperature changes. With built‐in strain sensing and wireless communication capabilities, the soft robot can record its locomotion routes and wirelessly transmit the key information to the following soft robot to keep both in disguise under thermographic cameras.
Inspired by cephalopod skin, an MXene robotic skin with tunable infrared emission is developed with four tightly integrated functions, including dynamic thermal camouflage, temperature sensation, strain sensation, and wireless communication. Equipped with the conformal MXene skins, “all‐in‐one” soft robots can perform adaptive thermal camouflage through actively monitoring environmental temperature changes and remotely sending/receiving crucial guidance information.
Bacterial resistance toward antibiotics is a world‐wide problem, and one potential solution to fight against the resistance is to develop multi‐mechanism antimicrobial agents to achieve synergistic ...performance. Titanium carbide (MXene) is an emerging 2D nanomaterial with antimicrobial ability to physically damage bacterial membrane and chemically induce oxidative stress, and it can be further conjugated with nanomaterials to improve its antibacterial performance. Herein, a synergistic antimicrobial agent is developed through conjugation of the ultra‐small gold nanoclusters (AuNCs) on MXene nanosheets. The conjugated AuNCs are effectively delivered into bacteria after bacterial membrane damage caused by MXene, generating localized reactive oxygen species (ROS) of high concentration to effectively oxidize bacterial membrane lipid for enhanced membrane broken, as well as bacterial DNA for violent fragmentation. Thus, the synergistic physical (via MXene) and chemical (via MXene and AuNCs) antimicrobial mechanisms lead to eventual bacterial death of both Gram‐positive and Gram‐negative bacteria, with low IC50 values of 11.7 µg mL−1 of MXene and 0.04 µm of AuNCs. Moreover, the crumpled MXene‐AuNCs structure is constructed to inhibit biofilm formation, which hold synergistic antibacterial ability of MXene‐AuNCs conjugation, hydrophobic surface to prevent bacterial attachment, and large surface area containing higher density of bactericides.
Synergistic antimicrobial agent is established through the conjugation of gold nanoclusters (AuNCs) onto the surface of MXene nanosheets. The synergistic antimicrobial ability is achieved physically (via MXene inseriting bacteria) and chemically (via MXene and AuNCs producing reactive oxygen species (ROS)) simultaneously.
Are children less susceptible to COVID-19? Lee, Ping-Ing; Hu, Ya-Li; Chen, Po-Yen ...
Journal of microbiology, immunology and infection,
06/2020, Letnik:
53, Številka:
3
Journal Article
Bacterial resistance toward antibiotics has been a worldwide threat; one way to fight against the resistance is to develop a multimechanism antibacterial agent to achieve synergistic performance. ...Graphene oxide (GO) is an emerging antibacterial agent combining multiple mechanisms (physical insertion and chemical disruption), and its rich functional groups enable the complexation/conjugation of nanomaterials to further improve antibacterial performance. Herein, a synergistic antimicrobial agent is established through the assembly of paramagnetic holmium ions and gold nanoclusters (AuNCs) onto GO nanosheets. The assembled nanosheets can be vertically aligned under weak and practical magnetic fields (<0.5 T ), providing high‐density sharp edges with preferential orientation to effectively pierce the bacterial membrane. Also, the conjugated AuNCs are efficiently delivered into bacteria to induce high oxidative stress, which strongly disturbs bacterial metabolism, leading to the death of both Gram‐positive and Gram‐negative bacteria. The antibacterial agent uses both physical (via oriented GO) and chemical (via GO and AuNCs) mechanisms to achieve synergistic antimicrobial performance with low IC50 values of 9.8 µg mL−1 on the basis of GO and 0.39 × 10−6 m on the basis of AuNCs. This multicomponent agent with dual antimicrobial mechanisms is expected to be a promising multifunctional‐antimicrobial agent with high biosafety.
A synergistic antimicrobial agent is established through the complexation of paramagnetic ions (holmium ions, Ho3+) and the conjugation of gold nanoclusters (AuNCs) onto graphene oxide (GO) nanosheets. The synergistic antimicrobial ability is achieved by disrupting the bacterial metabolism physically (via GO alignment under magnetic field inserting bacteria) and chemically (via GO and AuNCs producing reactive oxygen species) simultaneously.
Human skin serves as a multifunctional organ with remarkable properties, such as sensation, protection, regulation, and mechanical stretchability. The mimicry of skin's multifunctionalities via ...various nanomaterials has become an emerging topic. 2D materials have attracted much interest in the field of skin mimicry due to unique physiochemical properties. Herein, recent developments of using various 2D materials to mimic skin's sensing, protecting, and regulating capabilities are summarized. Next, to endow high stretchability to 2D materials, the approaches for fabrication of stretchable bilayer structures by integrating higher dimensional 2D materials onto soft elastomeric substrates are introduced. Accordion‐like 2D material structures can elongate with elastomers and undergo programmed folding/unfolding processes to mimic skin's stretchability. That stretchable 2D material devices can achieve effective tactile sensing and protecting capabilities under large deformation is then highlighted. Finally, multiple key directions and existing challenges for future development are discussed.
Progress in the use of various 2D materials to mimic skin's sensing, protecting, and regulating capabilities has been demonstrated in recent studies. Two important strategies to fabricate stretchable 2D material architectures are highlighted, including deposition on prestretched elastomer and back‐infiltration of elastomeric liquid. The accordion‐like 2D material structures can elongate with elastomers and undergo programmed folding/unfolding processes to mimic skin's stretchability.
Scalable nanoelectronics with energy‐efficient logic technology is crucial for next‐generation edge devices. Low‐dimensional semiconductors, such as transition metal dichalcogenides and single‐walled ...carbon nanotubes (SWCNTs), have tunable properties with reduced short‐channel effects. The unique properties of each material can be utilized owing to the heterogeneous integration of multiple semiconducting channels to form complementary metal‐oxide‐semiconductor (CMOS) logic. However, the integration remains challenging. This study reveals the realization of low static power hetero‐CMOS inverters by the integration of n‐type monolayer MoS2 and p‐type SWCNT networks. The balanced inverter exhibits a large peak gain of ≈67 at a supply voltage of 2 V with the customized design of the wafer‐scale synthetic process and channel integration. An ultralow standby power consumption of ≈5 pW and a practical peak gain of ≈7 at a reduced supply voltage of 0.25 V are achieved. A high noise margin (>70%) validates the circuit's tolerance to external noises and the dynamic analysis of the inverting amplifier in push–pull configuration exhibits a large AC gain. This work paves the way toward the wafer‐scale integration of low‐dimensional materials for low‐power nanoelectronics.
Wafer‐scale low‐power hetero‐CMOS inverters are realized by integrating monolayer MoS2 and SWCNT networks. An ultralow standby power consumption of ≈5 pW at a reduced supply voltage of 0.25 V, high NMs (>70%), and dynamic analysis in a push‐pull configuration are achieved. It paves the way toward the wafer‐scale integration of low‐dimensional materials for low‐power nanoelectronics.
Stretchable energy storage devices have become indispensable components toward energy autonomy for wearable electronic, implantable medical devices, and untethered soft machines. A Zn‐based battery ...with a neutral electrolyte could act as a competitive candidate for wearable/implantable electronics because of its intrinsic safety and high energy density. Therefore, it is highly desired to develop a synergistic combination of stretchable anodes/cathodes and neutral electrolytes for stretchable Zn‐based batteries. Herein, a scalable fabrication process is developed to produce stretchable Zn‐ion hybrid batteries composed of V2CTx MXene cathodes and zinc‐decorated Ti3C2Tx MXene anodes. To endow high stretchability to the Zn‐ion hybrid battery, both MXene‐based electrodes are fabricated with crumple‐like microtextures enabling reversible folding/unfolding behaviors to attenuate in‐plane stress while stretching. In comparison with the state‐of‐the‐art work, the as‐fabricated Zn‐ion hybrid battery features large deformability (50% strain), ultrathin device (≈170 µm), low areal weight (≈20 mg cm−2), and an ultralow self‐discharge rate (0.7 mV h−1), and demonstrates rechargeable and strain‐insensitive specific capacities of 118.5 and 103.6 mAh g−1 under 0% and 50% strains, respectively. Finally, with ultrathin and lightweight merits, the stretchable battery is further fabricated into a magnetically actuated soft robot with remote control, capable of crawling between two designated points for charging/discharging tasks.
A stretchable Zn‐ion hybrid battery, composed of reconfigurable V2CTx a MXene cathode and a zinc‐decorated Ti3C2Tx MXene anode, achieves strain‐insensitive mechanical properties and electrochemical performance. It performs magnetically robotic actuations and demonstrates synergistic advantages of light device weight, remote control, and user‐safe power supply. The integration of energy storage devices into soft robots facilitates the development of self‐powered soft machines towards futuristic applications.
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