Direct Ink-Writable Tough polyurethane acrylate elastomers for underwater intelligent monitoring Equipment

Polyurethane (PU) have attracted much attention in the field of intelligent information monitoring because of their excellent elasticity, durability and excellent adjustable properties. However, traditional polyurethanes have an overly long curing time. Moreover, the materials obtained by simply blending polyurethanes with inorganic conductive materials usually lead to problems such as uneven distribution of conductive substances and poor mechanical properties. Herein, to solve the above problems, a vinyl-terminated polyurethane prepolymer was synthesized for the preparation of photocurable elastomers. The conductive elastomer was prepared by the direct ink writing method using deep eutectic solvents (composed of choline chloride and 2-hydroxyethyl methacrylate) and polyurethane acrylate as raw materials. The addition of deep eutectic solvents provides the sensor with a stable signal monitoring ability while not affecting the elasticity of sensor. The sensors exhibit excellent mechanical properties with an optimum tensile strength of 8.2 MPa, good linearity (correlation coefficient is 0.997), wide sensing range (up to 280 %), high repeatability, stability and good solvent resistance. The prepared sensors can be used to detect a series of human body movements. What’s more interesting is that they can also be applied to water level monitoring and ionic conductivity measurement. More importantly, the DIW technology is adopted to meet different personalized customization needs. This work provides insight for the wide range of applications of DIW-printed elastomers in multi-functional sensing.