Ultrasonic-Induced Synthesis of Underwater Adhesive and Antiswelling Hydrogel for Strain Sensor

Abstract

To perceive the human body's multienvironmental mobility, intelligent flexible electronic equipment with an underwater motion monitoring function has potential research value in the field of intelligent detection. Hydrogels are widely used in the field of flexible electronics for their unique three-dimensional polymer networks. Due to the instinctive hydrophilicity of hydrogels, the swelling of hydrogels underwater and the formation of hydration coating on the surface become the primary obstacles to underwater applications. Herein, a hydrogel sensor that can achieve underwater utilization was prepared through copolymerization between hydrophobic and hydrophilic polymer monomers. The synergistic impact of electrostatic interaction, metal coordination, and hydrogen bonding ensured the hydrogel's remarkable underwater adhesive ability to a variety of substrates. The hydrophobic micelles and self-hydrophobization process induced from ultrasonic dispersion in the polymer matrix gave an outstanding hydrophobic performance (water contact angle of 130.4°) and antiswelling property (swelling ratio of 26% after 72 h of immersion), presenting unprecedented underwater adaptability. The above-mentioned hydrogel could be assembled into a flexible hydrogel sensor with satisfactory sensitivity (gauge factor of 0.44), ultrafast response rate (106 ms), and excellent cyclic stability, demonstrating accurate monitoring of complex human motions in water and air.

Intrinsically Nonswellable Multifunctional Hydrogel with Dynamic Nanoconfinement Networks for Robust Tissue‐Adaptable Bioelectronics

“…The gauge factor of the hydrogel is ≈1.17 which is less than widely adopted intrinsically metallic strain sensors, yet it is comparable to hydrogel‐based strain sensors (≈0.44–1.51). [ 42 ] Although hydrogel‐based strain sensors have a low gauge factor, they can endure large strains up to 100%, thus can broaden their applicability. The strain sensor property of the hydrogel was further examined to be durable through multiple stretching cycles (Figure 4I ).…”

Self-healing liquid metal hydrogel for human–computer interaction and infrared camouflage

“…The GF value of LM hydrogel-1.0 is about 3.42 in the strain range of 0-500%, and the GF value reaches 7.21 after the strain exceeds 500%, as shown in Fig. 4c, which is superior to most of reported hydrogel sensors 30,41,[47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66] (Fig. 4f).…”

Ionic Liquid/Water Binary Solvent Anti-Freezing Hydrogel for Strain and Temperature Sensors

“…With the rapid development of flexible electronics, smart equipment, and micro-nano processing technology, flexible wearable electronics have become the frontier of micro-nano electronics researches. − Flexible intelligent electronics, which integrate information on perception, response, and feedback, closely rely on the adaptability and reliability of integrated circuits and show outstanding advantages in the field of artificial intelligence, − human–computer interaction, , biomedicine, , and drug control release. , Based on various physical and chemical modifications, the multifunctional flexible strain sensors can achieve highly sensitive and rapid responses to different kinds of stimuli (e.g., stress, heat, and pH) through efficient conversion of electromechanical signals and profile wide application prospects in the area of wearable electronic devices. − …”