【Research Background】

 In recent years, flexible wearable skin sensors have attracted extensive research interest because of their potential applications in electronic skins, soft robots, and human-machine interfaces. Among them, conductive hydrogel-type epidermal sensors are widely used because of their good ductility, adjustable conduction channels and the flexibility of similar tissues. However, the conductive hydrogel-type epidermal sensor inevitably faces the challenge of water evaporation loss at room temperature, which seriously hinders its long-term application at room temperature. At the same time, the conductive hydrogel-type epidermal sensor requires additional adhesive tape for the connection between the skin and the human body. Therefore, the operation process is more complicated in practical applications. Therefore, it is very necessary to develop a conductive hydrogel-type epidermal sensor with reliable self-adhesiveness, long-lasting moisturizing performance and good self-healing ability. In recent years, by introducing organic solvents into hydrogels, wet organic hydrogels with long-term stability have been successfully established. At the same time, adding conductive fillers, metal nanowires, and carbon-based nanomaterials to the hydrogel polymer network can increase the conductivity of the hydrogel. MXene is a two-dimensional (2D) inorganic material. Due to its high specific surface area, excellent hydrophilicity and good conductivity in electrochemical energy storage and electromagnetic interference shielding, MXene has been widely explored. It can be used as an attractive conductive filler for the preparation of long-life, wet, conductive nano-composite organic hydrogels with improved mechanical and conductive properties.

【Achievement Introduction】

Recently, the Beijing University of Chemical Technology, Dr. Jia Xiaolong and Dr. Wan Pengbo in internationally renowned academic journal of Materials Chemistry C Journal published an article entitled: A Wearable, Self-Adhesive, Long-lastingly Moist and healable epidermal Conductive MXene from the Sensor Assembled Nanocomposites of The research paper proposes a self-adhesive, curable, long-lasting moist MXene nanocomposite organic hydrogel, which is used to assemble adhesive, self-healing and non-drying epidermal sensors. By combining the conductive filler MXene nanosheets with high specific surface area, reliable hydrophilicity and good conductivity with the polymer network of Alg-DA, Alg-PBA and PAAm using glycerol / water binary solvent as the dispersion medium, An MXene nanocomposite organic hydrogel that can be adhered, repaired and not dried is prepared. The obtained MXene nano-composite organic hydrogel has good self-healing ability, strong self-adhesive properties and 10 days of lasting moisturizing properties. MXene nanocomposite organic hydrogel can be used for biological monitoring of all-round movements of the human body, including finger bending, wrist bending, breathing and pulse movement. At the same time, the epidermal sensor can wirelessly monitor human activities through the connection with the wireless transmitter.

【Graphic introduction】

Scheme 1. Schematic diagram of preparation of self-adhesive, healable, and long-lasting MXene nanocomposite organic hydrogel

Figure 1.  Synthesis and characterization of MXene nanosheets.

Figure 2.  Water retention of MXene nanocomposite organic hydrogel.

Figure 3. Self-healing properties ofMXenenanocomposite organic hydrogel.

Figure 4. Self-adhesive properties of MXene nanocomposite organic hydrogel.

Figure 5. Photograph of MXene nanocomposite organic hydrogel for large-scale and tiny human motion monitoring.

Figure 6. The MXene nanocomposite organic hydrogel remotely monitors finger bending through wireless communication.

【Summary of this article】

     In summary, this paper proves that MXene nanocomposite organic hydrogel has a self-adhesive, non-drying and self-healing epidermal sensor. Using glycerin / water binary solvent as the dispersion medium, the conductive filler MXene nanosheet network was introduced into the polymer network to prepare MXene nanocomposite organic hydrogel. The strong hydrogen bond between water and glycerin in MXene nano-composite organic hydrogel hinders the evaporation of water, resulting in long-term moisturization of MXene nano-composite organic hydrogel (10 days).

Literature link:

https://dx.doi.org/10.1039/c9tc05575d.

Source: MXene Frontier