Influence of thermal effects on the dynamic behavior of blood droplets on a superhydrophobic surface

The high temperatures generated during the operation of high-frequency surgical electrodes can cause biological tissues (especially blood) to crust and adhere to the electrode surface, seriously affecting the quality and efficiency of the procedure. Currently, an effective anti-adhesion approach is to construct superhydrophobic microstructures on the electrode surface. However, the micro-mechanisms of antiadhesion under the influence of high temperatures are still incomplete. Herein, this study focuses on the dynamic growth and evolution of blood droplets on a superhydrophobic microstructured surface (SMS) under thermal effects above 100 °C. The research demonstrated that as the substrate temperature increases gradually, the internal fluid perturbation of the blood droplets intensifies, and the air layer trapped by the SMS is subjected to thermal expansion. Consequently, the SMS is unable to provide sufficient adhesion for the growth of the blood coagulum, leading to a significant decrease in the stability of its binding to the substrate and thus the formation of self-desorption. Particularly, it was discovered for the first time that the shell wall of the blood coagulum is layered, a phenomenon related to mass transfer in the Marangoni flow within the droplet under thermal effects. These detailed findings facilitate comprehension of the anti-adhesion mechanism of SMSs, thereby providing a theoretical foundation for the optimization of future surgical electrodes.