Dynamic behavior of biological droplets on heated, superhydrophobic microstructured surfaces

Abstract

Severe adhesion of biological fluids occurs on surgical electrodes due to a temperature-induced physical mechanism. By constructing surface microstructures and improving their hydrophobicity, it becomes a favorable choice for electrode anti-adhesion, but the related mechanisms are still not fully understood. Herein, we investigated the dynamic behavior of water and biological droplets on superhydrophobic microstructured surfaces (SMSs) heated over 100 ℃. The design inspiration of SMSs is derived from purple orchid leaves with excellent self-cleaning properties. The SMSs with Cassie-Baxter and Cassie impregnating states were selected and a flat surface was employed for comparison. Results show that the SMSs with the Cassie-Baxter state could reduce the Leidenfrost point to form a pseudo-Leidenfrost effect for water droplets. Furthermore, the dynamic evolution mechanism of plasma droplets on heated surfaces was first proposed, including base shrinkage, coagulation growth, and cap convergence. For the SMSs with the Cassie-Baxter state, the heat was carried away by vapor from the cavities at the contact interface, so that the growth height of the coagulation was lower than that of other surfaces. Additionally, the mentioned SMSs exhibited outstanding anti-adhesion performance and thermal stability. This study may contribute to understanding the anti-adhesion mechanism of surgical electrodes at the microscopic level.