In the past two decades, artificial skin-like materials have received increasing research interests for their broad applications in artificial intelligence, wearable devices, and soft robotics. However, profound challenges remain in terms of imitating human skin because of its unique combination of mechanical and sensory properties. In this work, a bioinspired mineral hydrogel is developed to fabricate a novel type of mechanically adaptable ionic skin sensor. Due to its unique viscoelastic properties, the hydrogel-based capacitive sensor is compliant, self-healable, and can sense subtle pressure changes, such as a gentle finger touch, human motion, or even small water droplets. It might not only show great potential in applications such as artificial intelligence, human/machine interactions, personal healthcare, and wearable devices, but also promote the development of next-generation mechanically adaptable intelligent skin-like devices.

Biomimetic skin-like materials, capable of adapting shapes to variable environments and sensing external stimuli, are of great significance in a wide range of applications, including artificial intelligence, soft robotics, and smart wearable devices. However, such highly sophisticated intelligence has been mainly found in natural creatures while rarely realized in artificial materials. Herein, we fabricate a type of biomimetic iontronics to imitate natural skins using supramolecular polyelectrolyte hydrogels. The dynamic viscoelastic networks provide the biomimetic skin with a wide spectrum of mechanical properties, including flexible reconfiguration ability, robust elasticity, extremely large stretchability, autonomous self-healability, and recyclability. Meanwhile, polyelectrolytes’ ionic conductivity allows multiple sensory capabilities toward temperature, strain, and stress. This work provides not only insights into dynamic interactions and sensing mechanism of supramolecular iontronics, but may also promote the development of biomimetic skins with sophisticated intelligence similar to natural skins.

Intrinsically stretchable conductors have undergone rapid development in the past few years and a variety of strategies have been established to improve their electro-mechanical properties. However, ranging from electronically to ionically conductive materials, they are usually vulnerable either to large deformation or at high/low temperatures, mainly due to the fact that conductive domains are generally incompatible with neighboring elastic networks. This is a problem that is usually overlooked and remains challenging to address. Here, we introduce synergistic effect between conductive zwitterionic nanochannels and dynamic hydrogen-bonding networks to break the limitations. The conductor is highly transparent (>90% transmittance), ultra-stretchable (>10,000% strain), high-modulus (>2 MPa Young’s modulus), self-healing, and capable of maintaining stable conductivity during large deformation and at different temperatures. Transparent integrated systems are further demonstrated via 3D printing of its precursor and could achieve diverse sensory capabilities towards strain, temperature, humidity, etc., and even recognition of different liquids.

A 3D printed thermo-responsive hydrogel is designed as a novel multifunctional skin-like sensor.

Given increasing environmental issues due to the large usage of non biodegradable plastics based on petroleum, new plastic materials, which are economic, environmentally friendly, and recyclable are in high demand. One feasible strategy is the bio inspired synthesis of mineral based hybrid materials. Herein we report a facile route for an amorphous CaCO 3 (ACC) based hydrogel consisting of very small ACC nanoparticles physically cross linked by poly(acrylic acid). The hydrogel is shapeable, stretchable, and self healable. Upon drying, the hydrogel forms free standing, rigid, and transparent objects with remarkable mechanical performance. By swelling in water, the material can completely recover the initial hydrogel state. As a matrix, thermochromism can also be easily introduced. The present hybrid hydrogel may represent a new class of plastic materials, the "mineral plastics".

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With growing interest in the fields of wearable devices, it is crucial yet rather challenging to develop skinlike soft conductive materials with customizable functionalities and human tissue-compatible mechanical properties. Previously reported electronic skins struggle to meet the demands for transparence, mechanical adaptability, and stable conductivity during deformation. The recent rise of ionic skins with inorganic salts or ionic liquids doping provides the intrinsic stretchability, however, dilemmas remain for their limited functionalities such as a monotonous appearance and a narrow scope of mechanical and sensory properties. Herein, we design a type of zwitterionic hydrogels from the perspective of molecular interactions, which successfully combines ultrastretchability (>10000% strain), high strength (∼300 kPa), self-healability (at room temperature within 12 h), 3D printability, distinct stimuli-responsibility, biocompatibility, and antibacterial activity. The wide spectrum of such excellent properties has been rarely reported before and along with the ability to fabricate bioinspired intelligent skins recreating multiple sensations and mechanical properties of human skin, covering a broad range of sensitivity, and displaying tunable visual effect. We believe this work will inspire the programming of stimuli-responsive skinlike materials and contribute to the smart devices for information transformation between natural and artificial interfaces.

Clay-based nanomaterials, especially 2:1 aluminosilicates such as vermiculite, biotite, and illite, have demonstrated great potential in various fields. However, their characteristic sandwiched structures and the lack of effective methods to exfoliate two-dimensional (2D) functional core layers (FCLs) greatly limit their future applications. Herein, we present a universal wet-chemical exfoliation method based on alkali etching that can intelligently “capture” the ultrathin and biocompatible FCLs (MgO and Fe2O3) sandwiched between two identical tetrahedral layers (SiO2 and Al2O3) from vermiculite. Without the sandwich structures that shielded their active sites, the obtained FCL nanosheets (NSs) exhibit a tunable and appropriate electron band structure (with the bandgap decreased from 2.0 eV to 1.4 eV), a conductive band that increased from −0.4 eV to −0.6 eV, and excellent light response characteristics. The great properties of 2D FCL NSs endow them with exciting potential in diverse applications including energy, photocatalysis, and biomedical engineering. This study specifically highlights their application in cancer theranostics as an example, potentially serving as a prelude to future extensive studies of 2D FCL NSs.