Temperature‐Responsive Ultrasonic‐Wave Engineering Using Thermoresponsive Polymers

Abstract

Artificial structures for controlling ultrasonic-waves are attractive for developing superb functions in sensing-imaging techniques. However, the complicated fabrication and fixed design associated with the particular wave limit the scalability. Herein, a versatile-reversible ultrasonic-wave engineering using programmable heating of local areas on thermoresponsive polymers is presented. As an abrupt shift of the elastic modulus occurs at selectively heated zones over the glass transition temperature, the drastic modulus change alters the S0 phase velocity of the Lamb wave within ultrasonic waves passing through the heated regimes. The modified wave propagation results in an active wavelength shift and wave refraction, which enables multifunctional programming of wave propagation pathways and wavefront shapes. Multiple functions such as reduced wavelength, wave steering, energy focusing and bifurcation are implemented in one nylon 6 thermoresponsive polymer, according to predesigned heating shapes. This work demonstrates the capability of temperature-responsive wave engineering in bulk solid media with only a heating configuration.

Extreme resilience and dissipation in heterogeneous elasto-plastomeric crystals

“…The applications range from novel lightweight space structures to soft robotics and actuation that require simultaneous capabilities in both mechanical resilience and energy dissipation. Furthermore, beyond the combination of the mechanically incompatible materials demonstrated in this work, geometric and topological combinations of dissimilar materials enable the attainment of superior thermal, 63,64 optical 40,65 and electrical properties 66,67 in harsh mechanical environments.…”

Optimization of elastic wave propagation in a reconfigurable medium by genetic algorithms with adaptive mutation probability

“…Each line was divided to 15 parts for which the laser shutter state could individually be controlled. In contrary to [39], where the heater shape was unchangeable, this gave us 10 × 15 individually controlled pixels where specimen can either be heated or not. The scan duration of 0.9 s was independent from the laser shutter state.…”

Effect of Embedded g-C3N4 Nanosheets on the Hydration and Thermal Response Behavior of Cross-Linked Thermoresponsive Copolymer Films

“…Stimuli-responsive polymers are able to respond to the external environment and exhibit reversible or irreversible changes in their chemical structure and physical properties. − Various types of stimuli, e.g., light, , gas, , pH, , mechanical forces, , temperature, , electric field, , and magnetic field, , have been applied to trigger the changes of the chain conformation, self-assembly, and solubility of stimuli-responsive polymers. As an important type of stimuli-responsive polymers, thermoresponsive polymers with a lower critical solution temperature (LCST) attract significant attention both in theories and applications due to their fast response, high sensitivity, and easy control of temperature response. − Typically, when the external temperature is below the transition temperature (TT), thermoresponsive polymers with LCST behavior are more hydrophilic, since intermolecular hydrogen bonds between water molecules and polymer chains can be formed.…”