Wearable electronics for personal healthcare and environment awareness are attracting more and more attention, where continuous energy supply is requisite and still faces great challenge. Here, a self‐powered electronic skin (e‐skin) system with multiple sensations as well as data processing and data visualization is developed. The core component is a hand‐shaped flexible thermoelectric generator functionalized as e‐skin, which not only harvests energy from body heat to supply power for the entire e‐skin system, but also plays a role of multisensory receptor. The e‐skin system is endowed with multifunction of sensing temperature and humidity, perceiving wind and motion, identifying material and monitoring acceleration, as well as displaying the sensing data on a liquid crystal display, all of which are powered by human body heat. The self‐powered flexible e‐skin provides an advantageous approach for applications in repair of skin injury, wearable healthcare devices, and wearable robots.
Printable and stretchable conductive elastomers have promising applications for epidermal and wearable electronics, soft robotics, etc. However, these conductive materials usually present poor performances in monitoring dynamic strains. The monitored signals are distorted and lose key physical signs, which limit their practical applications. Through investigating kinetic behaviors of conductive pathways along longitudinal and transverse directions in these conductive materials, the physical mechanism of signal distortion under dynamic strains is interpreted. To overcome this strain sensing problem, an Ag‐Ecoflex‐polydimethylsiloxane (PDMS) elastomer by printing Ag‐filler‐Ecoflex‐matrix ink on PDMS is proposed. Compared to other conductive materials, the Ag‐Ecoflex‐PDMS elastomer has preferable dynamic performances, embodying smaller overshoot response, higher strain sensitivity, and lower hysteresis. A deep‐learning‐based dynamic calibration method is proposed to successfully correct the sensing signals and eliminate the hysteresis error to 0.1%. Moreover, the proposed Ag‐Ecoflex‐PDMS elastomers gain high electrical conductivities owing to thermal expansion and contraction of PDMS substrate during the thermosetting of conductive ink, and thus can be both excellent stretchable sensors and stretchable conductors. Demonstrations of monitoring knee motion with high fidelity and human–robot collaborative playing ping‐pong validate superior accuracy and robustness of the Ag‐Ecoflex‐PDMS elastomers for monitoring human dynamic activities, human‐machine collaboration, virtual reality, etc.
Zwitterionic hydrogels have shown promise as effective
antifouling
materials in wound dressing applications owing to their robust hydrate
layer that offers protection against microbial infections. However,
the traditional covalently crosslinked zwitterionic hydrogels may
not be sufficient to adapt to irregular injury sites and fully address
microbial infections within the wound. Herein, we propose an injectable
zwitterionic hydrogel that utilizes dynamic hydrazone chemistry via
aldehyde and hydrazide functional groups and contains N-halamine antibacterial agents. The dual dynamic exchangeable covalently
and physically crosslinked structure resulting from the combination
of hydrazone bonds and zwitterion interactions facilitates instantaneous
gelation (within a few seconds) and extreme stability without any
degradation (for over 2 months). The hydrogels exhibit remarkable
fouling resistance against proteins and bacteria while demonstrating
excellent antibacterial performance in vitro without compromising
cytocompatibility. More importantly, we demonstrate their inherent
conductivity properties and sensitivity to external pressure. The
combination of the injectability, antifouling, antibacterial, cytocompatibility,
and electrical conductivity properties achieved offers the potential
to expand the utility of zwitterionic hydrogels in biological applications.
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