Ultrafast, autonomous self-healable iontronic skin exhibiting piezo-ionic dynamics

Abstract

The self-healing properties and ionic sensing capabilities of the human skin offer inspiring groundwork for the designs of stretchable iontronic skins. However, from electronic to ionic mechanosensitive skins, simultaneously achieving autonomously superior self-healing properties, superior elasticity, and effective control of ion dynamics in a homogeneous system is rarely feasible. Here, we report a Cl-functionalized iontronic pressure sensitive material (CLiPS), designed via the introduction of Cl-functionalized groups into a polyurethane matrix, which realizes an ultrafast, autonomous self-healing speed (4.3 µm/min), high self-healing efficiency (91% within 60 min), and mechanosensitive piezo-ionic dynamics. This strategy promotes both an excellent elastic recovery (100%) and effective control of ion dynamics because the Cl groups trap the ions in the system via ion-dipole interactions, resulting in excellent pressure sensitivity (7.36 kPa−1) for tactile sensors. The skin-like sensor responds to pressure variations, demonstrating its potential for touch modulation in future wearable electronics and human–machine interfaces.

Incorporating Wireless Strategies to Wearable Devices Enabled by a Photocurable Hydrogel for Monitoring Pressure Information

“…The high sensitivity lies in the electric double layer (EDL) formed at the electrode-ionic film interface, which has a separation of ≈1 nm for the positive and negative charges. [47,48] The charge separation is much smaller than that of conventional capacitive sensors (mostly 10-200 μm), thus signal enhancement of several orders of magnitude can be obtained. [49,50] This type of device generally exhibits ultrahigh unit area capacitance immediately, which is on the order of several μF cm −2 in a sub-MHz spectrum, more than 1000 times greater than that of the conventional parallel-plate capacitive sensors, ranging from tens to hundreds of pF cm −2 .…”

Photochemically driven one-step triple dynamic network formation in printable tough hydrogel for self-healing tubular sensors

“…Such features have inspired the design of various biomimetic materials that mimic human skin for advanced applications. [4][5][6][7][8][9][10] Among these materials, hydrogels, which are porous, soft, and have adjustable mechanical properties, 11,12 are readily available to prepare skin-like materials for potentialuse in creating bionics, 13,14 tissue engineering, [15][16][17] wearable devices, [18][19][20] etc.…”

Skin-mimetic tough polyurethane ionogel for use in soft ionotronics

“…36 Yaping Wang et al developed a skin-like ionogel by simply mixing IL and thermoplastic polyurethane (TPU), which possessed a large sensing range of strain (0.1-500%) and temperature (À40 to 100 1C), combined with high transparency (up to 94.3%) and antibacterial properties. 37 Although various chemical designs and modifications of PU have been carried out to achieve mechanical enhancement or sensitive signal capture, [38][39][40][41][42] there is usually a trade-off between the ionic conductivity and mechanical strength. As a result, developing a new type of PU ionogel with good mechanical toughness and ion conductivity, as well as accurate mechano-signal sensing, is still highly desired.…”